Microstructural and mechanical behavior analysis of magnesium matrix composites with varying Al₂O₃ content

Abstract

The Magnesium metal matrix composites demonstrate extremely high potentials of using light materials that are strong in the various industries. As the modern process, the fabrication and synthesis of Magnesium matrix composites which have fortified Al₂O₃ to different percentages of particles have been achieved. The Mg and Al₂O₃ composites are analyzed concerning the properties of the Al₂O₃ particle content which has different weight% of the particles in the X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) spectroscopy and properties of mechanical properties. The results show that the hardness as well as the wearrate of the composites increased respectively and the weight of Al₂O₃ powders composite decreased respectively. Characterization of mechanical properties indicated that the enhancement of the properties of pure magnesium by the reinforcement of Al₂O₃ particulates is beneficial. The resulting properties of metal matrix composites are reliant on a broad spectrum of variables and the current knowledge coupled with future research directions are brought up. Cost effectiveness of metal matrix composites in various applications will be the last determinant to their successful commercial production.

Introduction

Powder and conventional materials are poor in the unification of mechanical characteristics like strength, hardness, corrosion as well as wear resistance. In order to eliminate the issue, composite materials have been adopted in place of alloys and conventional materials¹. Pistons, cylinder head among others are some of the manufacturing industries that may employ the use of Al₂O₃ reinforced matrix composite to replace the heavier material in the processes due to its weak nature and low modulus at a higher temperature, corrosion and wear resistive properties are poor^2,3. One of the most suitable fabrication techniques of formation of the Mg-Al₂O₃ composites is the Powder metallurgy. It is inexpensive and the particulates are dispersed in the macromaterials in a uniformly distributed form, which contributes to the increase of the mechanical characteristics of the Mg-Al₂O₃ composites⁴. The substitution of harder and stiffer ceramics particulates and alloying elements in the matrix can overcome them. It will however be dependent on the kind, size and volume percentage of particulates to provide the best nature to these composite materials⁵.

One of the reinforcements that can be used is the nano-sized aluminium oxide ceramic particle (Al₂O₃)⁶.The hard Al₂O₃ particles used usually allow the composite structures to obtain high values of hardness and wear resistance which the metal matrix will not obtain on its own. They also enhance the resistance of the composite material to high temperature as well as inhibition of cracks propagation⁷. The fabrication technique that will be employed in this study due to its convenience, cost-effective, and adaptable nature is powder metallurgy, which can be conveniently utilized in mass production hence it is highly applicable within the automobile industry⁸. Hence, a composite material based on magnesium is created in presence of Al₂O₃ reinforcing particles with a view of exploring the effect and mechanism of nano-Al₂O₃ reinforcing particle number and shape in enhancing the mechanical properties of a magnesium matrix composites by a Powder metallurgy route⁹. The influence of Al₂O₃ reinforcement particle (at various levels of additions) on the hardness and corrosive properties was studied.

Powder metallurgy was convenient to use in making the Mg based materials through the coating process¹⁰. The production method (as one of the PM methods) could be the pressing method that has been effectively employed in obtaining the composite specimens with high relative densities, as well as in the processes of achieving the uniform dispersion of the reinforcement particles within the microstructure¹¹. scanning electron microscopy (SEM) and using line-scan profiles through energy-dispersive X-ray spectroscopy (EDX) can be employed to observe the production method¹². This is whereby it is used in electrical contacts field. By use of various reinforcement materials, i.e. ceramic particles, graphene etc.¹³. The MM powders and the SPS compacts of Mg and Al2O3 microstructures were observed under the scanning electron microscopy (SEM), as well as the X-ray diffraction (XRD) and transmission electron microscopy (TEM)/energy dispersive X-ray spectroscopy (EDS) techniques. Focused ion beam system and ion-beam polish system helped in the preparation of SEM and TEM samples respectively¹⁴.

Although numerous studies have investigated magnesium matrix composites reinforced with ceramic particles, much of the existing literature focuses on liquid-state fabrication routes such as stir casting, where issues related to particle clustering, oxidation, and poor interfacial control are prevalent. In contrast, systematic investigations on Mg–Al₂O₃ composites fabricated exclusively via powder metallurgy particularly with higher reinforcement contents and consistent processing parameters remain limited. Moreover, several reported studies lack direct correlation between processing conditions, microstructural features, and mechanical performance. Aluminium oxide (Al₂O₃) was selected as the reinforcement in the present study due to its high hardness, excellent thermal stability, good wear resistance, and chemical compatibility with magnesium under solid-state processing conditions. In addition, Al₂O₃ is widely available, cost-effective, and well suited for powder metallurgy routes, where it can enhance load transfer and restrict plastic deformation without inducing undesirable interfacial reactions. Accordingly, the present work aims to systematically investigate the influence of Al₂O₃ content on the microstructural, mechanical, and tribological behavior of Mg–Al₂O₃ composites fabricated via powder metallurgy, while maintaining consistent processing parameters and avoiding liquid-state processing artifacts. The objective of this study is to identify the effect of Al₂O₃ reinforcement content on the mechanical and wear behavior of magnesium matrix composites produced via a controlled powder metallurgy route.

Review of literature

The scanning electron microscopy with energy-dispersive X-ray spectroscopy showed the presence of neck and interface regions through the Al-Zr diffusion and presence of mullite phase through Al-Si diffusion as described by Murtiet al. in 2025¹⁵. The atomic diffusivities of Al-Zr, Al-Si, and O-Zr of the SPS samples were 2.562 × 10⁻¹⁵ m² s⁻¹, 7.221 × 10  ⁻¹⁵ m²s⁻¹, and 4.394 × 10 ⁻¹⁵ m²s⁻¹ m2/s, respectively, whereas the atomic diffusivities of the conventionally sintered samples were much lower at 0.092 × 10 ⁻¹⁵ m²s⁻¹, 0.577 × 10 ⁻¹⁵ m²s⁻¹, and 0.917 × 10 ⁻¹⁵ m²s⁻¹ . Consequently, SPS provided increased zirconia and mullite formation consistency with the traditional sintering.

A study by Beder et al. 2024¹⁶ utilized microstructure, mechanical properties, and wear resistance of Al₂O₃ particle-enriched Al the base or matrix composite of alloy akin to AlAsB. About the effects of 10, 20, and 40 weight% Al₂O₃, the microstructure, mechanical properties and dry wear resistance of the Al3CuMg matrix composites are studied. The higher the sample Al2O3 content, the higher is the level of hardness. The highest compressive strength is of the composite material which is reinforced with 10 weight% Al₂O₃ particles of 284 and 562.9 Mpa respectively. The increment in hardness of the samples being constant with the increase in the Al2O3 concentration may result in the sample with the constant percent of Al₂O₃-reinforced composite having the least volume loss.

Rahmani, Kaveh, et al.¹⁷(2020) have researched on mechanical and corrosion properties of Mg-MgO and Mg-Al₂O₃ composites using ECAE method.

Mg-Al₂O₃ and Mg -MgO composites could be prepared successfully by the use of ECAE. MgAl₂O₃ corroded at a lower rate than MgMgO. Composites that reinforced 30 and 20 vol percentages of alumina were also found to tell the highest compressive strength and hardness; this is 74% and 55% greater than that of the pure magnesium sample respective.Rahmani et al. in 2020¹⁸ used Al₂O₃ nanoparticles prepared through a single-action press (SP) and double-action press (DP) under 300, 500, and 700 Mpa pressure as reinforcement to compare and display the physical, tribological, and corrosion properties of magnesium matrix nanocomposite reinforcement when guaranteeing the presence of Al₂O₃ that brought positive changes to their characteristics. The wear rate of the 5 vol%-700 MPa-DP was 14 per cent less than that of 5 vol%-700 MPa-SP. The higher the percentage of nanoparticles, the higher the rate of corrosion. The 5 vol% corrosion rate was 520 higher compared to that of pure Mg-700 MPa-DP.

Ghanararajan et al. (2015)¹⁹ state that discontinuously reinforced AMMCs may be hot extruded, which leads to improved bonding, reduced porosity, and fractured insular agglomerates, which positively influence the mechanical properties of these alloys. To prepare aluminum-based composite, To prepare 0, 3, 6, 9 and 12 weight% of Al2O3 particles that have been reinforced as using mass stirrent of the Al 1100 (Mg) alloy through the melt stir mechanism. The same composites are then hot extruded. In the case of extrusion alloys and composites mechanical properties such as tensile strength and hardness and microstructural studies such as Scanning Electron Microscopy (SEM) with EDX will be studied.

In 2020, Kumar et al. had produced and fabricated magnesium matrix composites, which were reinforced with Al2O3 with varying weight percentages and various particle sizes through the stir casting process²⁰. The influence on the mechanical properties of the composites density, porosity, hardness and tensile strength under the different weight per cent levels of Al₂O₃ particles, were experimented. These findings show that as the content of Al₂O₃ particles weight in the composites, the hardness and tensile strength of the composites, also, increased.

ThirugnanaSambandhamet al. 2019 article²¹ focuses on the wear characteristics of magnesium based metal matrix composite reinforced with alumina nanoparticles (50 nm) stirred castings. The wear test is performed in the machine setup of a pin-on disc tester with hardened steel counter-face under dry sliding conditions with load of 10 N and 20 N sliding at different speeds (200, 400, 600 and 800 rpm) of 0–180 s at room temperature.

Qun Wang et al. (2024)²² explored the possibility of using Al₂O₃micropowder (ALMP) to improve cementitious materials’ durability and mechanical performance²².the impact of varying ALMP doses on the mechanical performance, workability, and longevity of high-strength mortar (HSM) made by IBA. Furthermore, the impact of ALMP on the dynamic modulus of elasticity (DME), microstructure, and ultrasonic pulse velocity (UPV) of HSM was also examined.The study’s conclusions might have useful implications for enhancing IBA’s resource efficiency in cement-based materials.

The sintering method, which is simply a mixture of the particles of both materials in powder process, was conducted by Srinivas et al. in 2020²³. Three factors are put into consideration when making FGM which include a sintering temperature and compacting pressure. The FGM is comprised of four layers with the following 90% Al + 10% SiC, 90% Al + 5% SiC + 5% MgO 2 and 100% pure Al. Mechanical analysis is done to check the compressive strength of the material FGM and hardness. The results of the mechanical analysis indicate that FGMs have higher compressive strength, microhardness and macrohardness than the composite materials since the FGMs are found to be in the range of compressive strength 315 Mpa, 1.26 Gpa, and 1.87 Gpa, microhardness and macrohardness respectively.

The magnesium-based composites were successfully made utilizing an autonomously controlled stir casting system, according to Singh, A., & Bala, N. (2019)²⁴. Al2O3 particles with weight percentages ranging from 3 to 12 were implanted in a pure magnesium matrix. Cast samples were subjected to hardness testing. Pin-on-disk wear experiments were performed with fixed sliding velocity (1 m s⁻¹) and various loads (1–5 kg). When compared to unreinforced magnesium, the hardness and wear resistance of as-cast composites greatly increased. This improvement continued up to 9 weight% of the reinforcing content, but it reduced as more was added. The dispersion hardening caused by the inclusion of hard reinforced particles was credited with improving the hardness and wear performance.

In 2024, Murali et al. used a blend press sinter powder metallurgy method to create a hybrid magnesium composite that contains micro Al2O3 and nano TiO2²⁵. By submerging the composites in a synthetic stimulated bodily fluid (SBF) created in the lab, the corrosion properties were examined. The corroded surfaces are analyzed using the Tafel Polarization. The composites’ corrosion resistance changed in a way that was quite similar to that of pure magnesium.

In 2024, the critical focus of Xuan, S. et al. was given to the design of the technology that targeted the regulation of the characteristics of other materials based on magnesium aluminum oxide (MgAl₂O₄)²⁶. The stoichiometric spinel was sintered ideally at 50 °C lower than others since the ratio of molar had transformed the microstructure of spinel. In particular, the spinel grains in stoichiometric spinel swelled and apparent structure was created and this allowed the sintering process to be completed and allowed the optimum performance. Particularly, it possessed its apparent porosity of 0.44% and flexural strength of 112.62 Mpa. These findings demonstrated that the densest stoichiometric spinel that contained the highest ion diffusion was the most preferred.

In 2022, Ilić, I., Petrović, Z., et al.²⁷ suggested a reliable computing procedure to determine pinhole initial failure loads during layered composite structures. Finite element method (FEM) is used to determine the distribution of stress about the fastener hole. The combination of the Tsai-Wu first failure criterion and the Chang-ScottSpringer characteristic curve model is used to obtain the joint failure. The particular consideration in this work is provided to pin-load distributions and their effect on the load level of failure and its location. The earlier work performed the initial analysis of failure by the cosine distribution between the pin/lug joint that was mechanically fixed.

Several studies have explored the enhancement of mechanical and thermal properties of metal matrix composites through the incorporation of nanoparticles or ceramic reinforcements. For instance, multiphysics-guided design approaches have been applied to optimize the integration of nanocomposites for energy harvesting, demonstrating the critical role of microstructure on performance²⁸. The effect of composite material derivation using bio-based additives has been investigated, showing accelerated material functionality through enhanced microstructural properties²⁹. Regression-based modeling and physics-informed deep learning techniques have also been successfully employed to predict and optimize the thermal and electrical characteristics of epoxy-based nanocomposites, highlighting the importance of microstructural control in achieving desired mechanical and functional behavior^30,31. Moreover, the study of corrosion inhibitors in metal matrices emphasizes the interplay between microstructure and long-term material stability, which is crucial when designing reinforced metal composites³². Strength, durability, and functional performance of lightweight alloy systems have all been found to be significantly influenced by microstructural tailoring. Precipitation evolution directly governs the hardening efficiency and structural stability of ultralight magnesium alloys, according to studies on phase transformation behavior during thermal aging³³. In hybrid Mg/Al systems, interfacial waveform formation improves metallurgical bonding and load transfer capability, according to high strain-rate joining studies³⁴. Post-processing heat treatments greatly improved ductility and microstructural uniformity in biodegradable alloy systems³⁵, while additive manufacturing routes were demonstrated to refine precipitates and improve tensile response through controlled thermal cycles³⁶. By improving grain structure and surface integrity, rolling and thermomechanical processing further enhanced mechanical reliability, corrosion resistance, and antibacterial response³⁷. Interfacial stability, microstructural refinement, and defect control are critical to achieving superior mechanical performance and long-term reliability in next-generation composite materials, according to related research on advanced joints, cyclic loading behavior, electromagnetic absorption coatings, metallic glass composites, and multi-energy surface modification^38–42.

Motivation of the research

Available literature reveals that an attempt has been made so far to fabricate Mg-based composites by the simultaneous incorporation of (hybrid) composites in an economical manner. An analysis of the past literature reveals that experiments and researches on magnesium matrix composites are extensive and varied. Extruded samples were subsequently characterized for investigating their microstructural and mechanical properties.

The aim of the present paper is to study the Magnesium Aluminium oxide reinforced particulate composite using Powder metallurgy. The microstructural properties and the mechanical and corrosion properties of Mg-Al₂O₃ composites formed with the help of are used to measure the effectiveness of the proposed strategy. This type of arrangement allows the collection of the powders with no process before the compaction or scanning of the powder to enable the fabrication time and cost to decrease substantially. Composites development is the job of the modern work of PM to investigate the opportunities to implement the composites in structural components and some mechanical features of this kind of composites. Increasing the content of Mg composites in 10–40% weight% of Al2O3 particulate reinforcement increased mechanical properties of the Mg composites including hardness, compressive strength, wear rate, and SEM, FTIR, XRD of this composite.

Materials and methods

In this study 90–60%weight ofmagnesium powder and 10–40% Al₂O₃ particles were employed. Aluminum oxide particles are a common ceramic powder filler that, because of their hardness, can also be employed as an abrasive. Al₂O₃(aluminum oxide) is utilized as reinforcement. The characteristics of the matrix material (Mg) and reinforcement (Al₂O₃), as well as the quantity of particulate Al₂O₃ reinforcement. Alumina is a white, crystalline substance that is synthesized from Al₂O₃ and utilized as a raw material to make aluminum metal. 90 million tons of alumina are produced annually worldwide.All Mg–Al₂O₃ composites investigated in this study were fabricated exclusively using the powder metallurgy route, involving powder blending, cold compaction, sintering under controlled atmosphere, and extrusion. No liquid-state or stir casting processes were employed.

Fabrication of Composites

Blending a powder with lubricants or combining a powder with a binder. To prevent contamination and deterioration, metal powder is mixed and blended under carefully monitored conditions. It results in a homogeneous distribution of particle size and shape. By adding lubricants to the powder in amounts between 0.25 and 0.5% by weight, it enhances metal-powder interaction and improves the powder’s flow properties. It is cost-effective and provides homogeneous distribution of particles in the matrix materials that enhance the mechanical properties of the Mg-Al2O3 composites in Fig. 1.

Fig. 1.

Materials in powder form.

Weight and size

The maximum tonnage capacity of the forming presses (about 1000 tons) limits the part’s weight and size. A ferrous PM component weighing 2 kg would be considered large. Re-entrant features, however, are impossible to produce since they would prevent the part from being ejected from the die in Fig. 2.

Fig. 2.

Compacting die (30 × 10) mm.

Load

The influence of the residual porosity in the product limits the strength level of parts that are normally die pressed to a certain extent.

Procedure of powder metallurgy

All the Aluminium oxidecomposite specimen was produced by powder metallurgy. The process of powder metallurgy gave the composites remarkable strength and is a reliable method for forming them into a variety of shapes. The PM steps are as follows:

• (i)Blending The 5-weight% of Aluminium oxide and Mg powders were first physically mixed in a milling container that was hypothetically built using a steel ball-to-powder weight ratio of 6:1. An automatic lathe machine was fastened to the container to combine the powder⁴³. Mg-Al₂O₃ Components are combined with the powder, to additives Lubricants are added. Until a uniform mixture is achieved, mixing is carried out. This composition has a crucial role in defining the material’s characteristics. Additionally, Mg-Al₂O₃ are combined with powders to reduce die wear and friction between die surfaces and powder particles during compaction. The intended results will determine long to mix, and excessive mixing will cause the particles to harden and the size to decrease. To avoid demixing, the blending process’s duration and speed are meticulously regulated. This occurs when variations in particle size or density cause powders to separate. In this study, powder blending, cold compaction, sintering under inert atmosphere, and post-sintering extrusion were conducted as distinct and sequential steps of a powder metallurgy route; chemical vapor deposition was not employed.
• (ii)Compaction of powder A hydraulic press machine was used to press the mixture at 100-200Mpa and 25 mm diameter of green compacted sample was formed.Powder compaction is typically broken down into phases, each of which is thought to be connected to the mechanical and physical characteristics of the Mg-Al₂O₃ powder particles.Powder is typically compacted at room temperature in a die and punch assembly. The Mg-Al₂O₃ powder undergoes uniaxial compression as the compaction pressure rises. Mg-Al₂O₃ Powder particles mostly undergo compressive stress during compaction, although particles close to the die wall surface also exhibit some tensile response.
• (iii)Sintering The compressed samples were heated at 15 °C/minute in a Muffle furnace between ambient temperature (approximately 25 °C) and a temperature scale of 400–600 °C. Additionally, the holding period was modified, going from 120 to 180 min.As seen in Fig. 3, the sintering procedure was carried out using Chemical Vapour Deposition (CVD). One type of heat treatment used in powder metallurgy is called CVD.

Fig. 3.

Chemical vapour deposition (CVD).

As the argon gas is continually inserted at a rate of 13 °C/min, the intentional sintering process heats up to 550 °C. The furnace remains at 550 °C for 45 min once it reaches that temperature, which is necessary for improved bonding. After that, the pellets are kept in the furnace until the temperature reaches 37 °C, which is the ambient temperature. The metals can fuse firmly while maintaining their advantageous characteristics at a specific sintering temperature. With the aid of an extrusion die, the pellet’s real diameter of 25 mm is lowered to 20 mm. For our necessary testing procedure, a pellet’s diameter is decreased using an extrusion die. The die’s diameter on one side is 15 mm, which is marginally smaller than the 10 mm diameter on the other end, as seen in Fig. 4.

Fig. 4.

Extrusion die.

The plunger is secured on top of the die once the pellet has been inserted into it. After that, the universal testing machine is used to hold the extrusion die. Through the top punch, the load is applied to the plunger; as the load is applied continually, the pellet exits from the lower diameter side, and its sampleis shown in Fig. 5.

Fig. 5.

Samples of Mg and Al₂O₃specimens.

All Mg–Al₂O₃ composites were fabricated using identical powder metallurgy parameters, including a compaction pressure of 200 MPa and sintering at 550 °C for 120 min under an argon atmosphere, as summarized in Table 1.

Table 1.

Powder metallurgy processing parameters.

Parameter	Value
Compaction pressure	200 MPa
Sintering temperature	550 °C
Holding time	120 min
Heating rate	15 °C/min
Atmosphere	Argon

Experimental setup of the present study

This technique involves mechanically churning molten aluminium to disperse the reinforcing phases, which are typically in powder form. Mg-Al₂O₃ composites can be fabricated using powder metallurgy by combining magnesium powder with Al₂O₃ particles and then consolidating the mixture through techniques like compaction and sintering. The powder mixture utilized to analyze the various properties with samples like Mg varying from 90% to 10% and Al₂O₃ varying 10–40%. Using mechanical stirring, reinforcement of Al₂O₃ is added to a magnesium matrix metal. The ISO-4892 standard was primarily followed in the construction of the experimental setup. ASTM D2865M06 and other standards are also utilized as guidelines.

Chemical composition of materials

The properties and chemical properties of the materials Mg/Al₂O₃are presented in Tables 2, 3 and 4 above. Characterization shows that magnesium as-cast contains 95.4% Mg, meaning that a composition level of up to 99% in conformity with the initial mass balance is still possible. However, the traits themselves would not be significantly impacted by these factors. The results for the composite indicate that while the content of magnesium falls on the 0.20 and 0.25 volume of fraction-% micro Al₂O₃⁴⁴, the number of reinforcing particles increases. Agglomeration was the cause, and the liquid composite reacted with the air for an excessively lengthy time because the liquid was not poured into the mold quickly enough.

Table 2.

Properties of magnesium and aluminium oxide.

Composites	Colour	Melting point (0C)	Boiling Point (0C)	Density(g/cm3)	Poisson ratio	Hardness (MPa)	Thermal conductivity (W/mK)
Magnesium (Mg)	Shine grey	656	1090	1.88	0.32	14	78
Aluminium oxide	White	2078	2977	3.71	0.25	16	26

Table 3.

Chemical composition of Mg.

Chemical composition of Mg	Al	Zn	Mn	Si	Cu	Ca	Fe	Ni	Mg (%)
Weight (%)	3.2	0.9	0.3	0.1	0.04	0.03	0.005	0.005	95.4

Table 4.

Chemical composition of Al₂O₃.

Chemical composition of Al2O3	CaO	TiO3	Fe2O3	other	Al2O3
Weight (%)	1.1	1.8	0.8	0.02	92.93

Characterisation of properties

The composites’ compression tests verify that the Magnesium and aluminiumpowder compression strength is increased by the inclusion of ceramic reinforcement. Destructive testing was applied to every sample. Each specimen was examined using a technique based on Archimedes Theory to determine its true density prior to the destructive test. Properties of Metal Matrix composites with particulates of magnesium and aluminium oxide⁴⁵. The outcome demonstrates how adding reinforcement to the matrix improves the mechanical properties. The characteristics of the constituent materials determine the mechanical properties of fiber-reinforced composites.

Mechanical properties

• (i)Compression Test. To obtain the compressive strength of the produced samples compressed in room temperature with the help of an Instron apparatus under uniaxial conditions (strain rate: 0.008 s-1), a quasi-static compression test (ASTM E9) was conducted. The specimens were greased and polished on the upper and lower sides of their surface as far as possible in order to reduce the effects of friction. After then, pressure was added and maintained until the sample failed completely. This test is essential for determining a material’s modulus of elasticity, compressive strength, and other mechanical properties. Compressive strength is a key indicator of the maximum stress a material can withstand under compressive loading before failing. The compressive test is important because it can reveal important information about how materials behave mechanically when subjected to compressive stresses.

  Finding a material’s behavior or response and determining its related compressive qualities are the objectives of compression testing. With the exception of applying strain in the other direction, compressive testing.

• (ii)Hardness Test. The following procedures were used to calculate hardness: polished magnesium and Al₂O₃ particles were made, magnesium samples were added, and the polished sample was placed on Vicker’s hardness scale. The hardness of different magnesium composite compositions reinforced with varying weight percentages of Al₂O₃ was measured using Vicker’s hardness tester. As the alumina content increases, the hardness values of the Iso-UST composites are 12%–17% greater than those of the AC-UST composites. The hardness increase is in line with earlier research. The specimen’s hardness was assessed at various points, and the average value was determined. The mean of the recorded values after getting the indents to a minimum of indents on each sample through arithmetic averaging was calculated to derive the average hardness values which were tabulated as mean SD values⁴⁶.
• (iii)Wear Test. A pin-on-disk machine was used to perform the wear test, which involved sliding a specimen 100 m into a tougher substance. Because the indenter penetrates the sample more deeply when the applied load is increased, a larger metal removal rate is made possible. For hard/hard complete joint prosthesis, wear testing under concentrated contact pressure is unavoidable to verify the material’s dependability and safety. However, because the wear process is a type of complex system, it is impossible to fully replicate it in a simulation test following micro-separation or impingement in artificial joints.Sliding velocity, normal load, sliding distance, and filler content are the four main elements taken into consideration while conducting a sliding wear test.The weight, sliding speed, and sliding distance were all adjusted within the specified range, and the track diameter was set at 80 mm.The load forces the arm to stay in touch with the disc once the surface in contact wears down. The maximum wear is calculated using the signal produced by this arm movement.

Microstructural properties

• (i)SEM and EDX Test. The EDX analysis was then used to focus on the chemical composition of the phases developed at the contact of particles, the EDX point analysis, and the SEM images of microstructures at the interfaces. In the interfaces, the EDX analysis indicated the presence of the elements of Al, O, and Mg. It was also demonstrated how the intermetallic compounds which had dispersed between the magnesium particles in order to create void spaces (porosity) at the contact point between particles and did not allow a complete contact to occur. As a measure of getting relevant data on the constituents of the composite materials, EDX analysis was conducted presenting different elements and the percentage they occur. The sample that had the best value was created through the process of automatic grinding of abrasive paper using a machine and polishing on a velvet fabric using micron alumina paste. Microstructure characterization was done after sample preparation using an optical microscope which was used to observe microstructure and determine the grain size of composite specimens which had a value of hard composite, composite reinforcement and an XRD test to identify which phase had formed in the composite although a high volume fraction of the reinforcing material had the most.
• (ii)Fourier transform infrared (FTIR) spectroscopy Test. Agilent Technologies’ “Cary 630 FTIR spectrometer” was used for FTIR analysis to identify structural alterations brought on by UV aging and the oxidation of the hydrocarbon chain. Following each cycle, an analysis was conducted using the absorption form. UV light caused variations in absorption peaks in all of the samples⁴⁷.

Results and discussion

The findings of wear, microstructural, and mechanical tests of magnesium-Al₂O₃ composites using ASTM standards were covered in this section. Al₂O₃ and magnesium contents ranged from 10 to 40% and 60 to 90%, respectively.

Results of compressive test

As shown in Table 5; Fig. 6, the compressive strength of Mg–Al₂O₃ composites increases with Al₂O₃ content up to 30 wt%, reaching a maximum value of 204 MPa for Mg (70%) + Al₂O₃ (30%). A further increase in reinforcement content to 40 wt% leads to a reduction in compressive strength (186 MPa), which can be attributed to particle agglomeration and increased porosity.Addition of reinforcement phase further resulted in weakening of the strength. Addition of more of the reinforcing particle in the composition led to decreased compressive strength⁴⁸. Compression strength increased when Al₂O₃ particles were uniformely distributed in the composite which was less than the Mg alloy. The compressive stress strain curve of Mg and Al 2 O3 at various weight compositions. From the graph, the addition of Al2O3 weight in the magnesium increased the compressive strength. The best result for compressive strength was in the content of Mg(70%) + Al₂O₃ (30%). However, an additional increase in the content of Al₂O₃resulted in a decrease in the final compressive strength of the composite. The strain value increased the stress also increased in Mg and Al₂O₃, In Mg(60%) + Al₂O₃ (40%) the stress as 165 MPa with strain as 2.2%, The compressive strength of the composites is increasing and the strains are decreasing with increased weight of the Mg and Al₂O₃ composite and minimum strain was noted in case of Mg(90) + Al ₂O ₃ (10) as shown in Fig. 6.

Table 5.

Comparison of compressive strength.

Sample Specimen	Compressive strength (MPa)
Pure Mg	135
Mg(90%) + Al2O3 (10%)	198
Mg(80%) + Al2O3 (20%)	200
Mg(70%) + Al2O3 (30%)	204
Mg(60%) + Al2O3 (40%)	186

Fig. 6.

Compressive stress–strain of Mg–Al₂O₃ composite samples.

Results of wear test

Table 6 displays the wear rate of sample specimens from the wear test at a sliding distance of 300 m with a typical load of 5 N⁴⁹. The wear rate of the basic material (Mg + Al₂O₃) was found to be higher than that of the samples. The specimen samples were able to reduce the mass loss during the wear test thanks to the uniform distribution of Al₂O₃ particles and the increase in rotating speed.

Table 6.

Wear test results.

Sample Specimen	Initial weight (g)	Final weight (g)	Wear rate in (mg\m)
Mg(90%) + Al2O3 (10%)	2.77	2.69	0.336
Mg(80%) + Al2O3 (20%)	2.78	2.70	0.42
Mg(70%) +  Al2O3 (30%)	2.92	2.59	0.45
Mg(60%) + Al2O3 (40%)	2.75	2.46	0.58

Figure 7; Table 6 show the wear rates of Mg–Al₂O₃ composites tested under a normal load of 5 N and a sliding distance of 300 m. The composite containing 10 wt% Al₂O₃ exhibits the lowest wear rate (0.336 mg/m), indicating improved wear resistance compared to higher reinforcement levels. As the Al₂O₃ content increases beyond 20 wt%, the wear rate increases, reaching a maximum of 0.58 mg/m for the composite with 40 wt% Al₂O₃. This behavior is attributed to particle agglomeration, interfacial debonding, and third-body abrasion caused by detached ceramic particles. The results demonstrate the influence of reinforcement content on wear behavior under laboratory conditions, but further testing under varied loads, temperatures, and environments is required before assessing application-specific suitability⁵⁰.

Fig. 7.

Wear rate of Mg/Al₂O₃ composite.

Results of hardness test

The Vickers hardness of the Mg–Al₂O₃ composites increases with increasing Al₂O₃ content, as shown in Table 7; Fig. 8. The hardness rises from 42.56 HV for pure magnesium to a maximum value of 66.00 HV for the composite containing 30 wt% Al₂O₃. This improvement is attributed to the presence of hard ceramic Al₂O₃ particles, which restrict plastic deformation and enhance load-bearing capacity. A slight decrease in hardness is observed at 40 wt% Al₂O₃, likely due to particle agglomeration and increased porosity, which reduce the effectiveness of reinforcement.The hardness of different magnesium composite compositions reinforced with varying weight percentages of Al₂O₃ was measured using the Vickers’ hardness tester in Fig. 8. Results of Hardness Measurements of Mg/Al2O3 Composites are in Table 7. The hardness of different magnesium composite compositions reinforced with varying weight percentages of Al₂O₃ was measured using the Vickers’ hardness tester. A diamond indenter was utilized to impart load in this hardness test. Vickers’ hardness number is displayed against the different percentages of Al₂O₃ reinforcements in the specimens of magnesium composites. If the amount of Al₂O₃ increases, the hardness also increases, aminimum hardness of42.2, 42.58, and 46.2foreach specimen at the combination of Mg (90%) + Al₂O₃ (10%). It displays how the toughness of magnesium metal matrix composites grows as the weight% rises. Besides, weight-reinforcing pure Mg using Al ₂ O ₃ particles offers the lowest hardness of Mg ₂ O ₃ reinforced pure Mg than Mg ₂ O ₃ reinforced composite.The increases in hardness for Mg matrixcomposites (90%,80%,70%,60%) with increasing weight% (10, 20, 30, and 40 wt%) of Al₂O₃ than that of pure Magnesium. Mg (70%) + Al₂O₃(30%) composites have highest hardness because of distribution of Al₂O₃ composite and their characteristics.

Table 7.

Results of hardness measurements of Mg/Al₂O₃ composites.

Hardness Values (HV)
Sample ID	Specimen 1	Specimen 2	Specimen 3	Average
Pure Mg	42.2	42.58	42.9	42.56
Mg (90%) + Al2O3(10%)	47.44	47.56	46.2	47.066
Mg (80%) +  Al2O3 (20%)	58.25	59.2	59.6	59.016
Mg (70%) + Al2O3 (30%)	65.23	65.89	66.89	66.003
Mg (60%) + Al2O3 (40%)	56.3	56.25	59.5	57.3

Fig. 8.

Hardness of Mg-Al₂O₃ composites.

Scanning electron microscopy (SEM)

Figure 9 presents SEM micrographs of Mg–Al₂O₃ composites with varying reinforcement contents. At lower Al₂O₃ levels (10–20 wt%), the microstructure shows a relatively continuous Mg matrix with a fairly uniform dispersion of Al₂O₃ particles and limited visible porosity. As the Al₂O₃ content increases to 30 wt%, localized particle clustering becomes more evident, although the matrix continuity is largely maintained. For the composite containing 40 wt% Al₂O₃, an increase in visible porosity and particle agglomeration is observed. Interfacial gaps and particle pull-out features suggest weaker interfacial bonding and reduced densification efficiency at high reinforcement content, which is consistent with the observed reduction in compressive strength and hardness. The analysis of EDX confirms that the elements of Mg, Al, and O are present in the composite, which confirms the effective integration of the particles of Al 2 O 3 into the Mg matrix.However, no conclusions regarding interfacial reaction products or bonding strength are drawn solely from EDX data. A detailed quantitative analysis of porosity fraction, grain size distribution, and interfacial bonding strength would require advanced image analysis, EBSD, or TEM investigations, which are beyond the scope of the present study.

Fig. 9.

SEM image of various test specimens.

Fourier transform infrared (FTIR) spectroscopy

Table 8 shows were examined using FTIR spectroscopy. The measurements were taken between 4000 and 500 cm⁻¹. Dolomite was recognized as one of the sample components since all of these FTIR bands were found in the samples whose codes were previously reported. Best intensity as 94.662 in Mg(80%) + Al₂O₃ (20%), its compared to other combination the difference as 0.23 to 0.28% with better area and also the maximum peak value as 2945.1 in Mg(60%) + Al₂O₃(40%) with minimum area 0.33, from this overall study all samples are best for aircraft and other engineering applications.

Table 8.

FTIR results for various compositions.

Samples	Peak	Intensity	Corr.Intensity	Base(H)	Base(L)	Area	Corr.Area
Mg(90%) + Al2O3 (10%)	1105.14	94.266	3.077	1230.5	1022.2	3.259	1.102
Mg(80%) + Al2O3 (20%)	1423.37	94.662	4.609	1449.41	1383.83	0.634	0.433
Mg(70%) + Al2O3 (30%)	2400.25	94.447	0.844	2478.36	2390.6	1.252	0.162
Mg(60%) +  Al2O3 (40%)	2945.1	97.411	0.659	2954.74	2916.17	0.33	0.093

The FTIR spectra of the minerals displayed in Fig. 10 are thought to indicate the Mg+Al₂O₃stretching vibrations at 800–1250 cm⁻¹ and its related bending bands at 400–600 cm–1. Different mineral groups can be easily distinguished from one another thanks to the distinct absorption bands formed by the Mg+Al₂O₃ groups in the FTIR spectra, which span the range of 4000 to 500 cm⁻¹. The stretching vibrations of Al₂O₃ groups around 4000–500 cm⁻¹ are believed to be the most crucial spectrum region for identifying aluminous minerals. A particular FTIR spectrum can reveal details on the functional groups of the gases at a certain time and temperature at any point along its curve.

Fig. 10.

Results of the FITR test.

X-Ray diffraction (XRD)

Figure 11 displays the Al₂O₃ and powder materials XRD pattern. The crystalline structure of Al₂O₃ is revealed by the pattern. The powder X-ray diffraction pattern for Al-Mg composites at weight% Al₂O₃PM content. Five distinct peaks that corresponded to FCC aluminium were visible in the X-ray diffraction patterns.

Fig. 11.

XRD patterns of the examined samples.

Figure 11 shows the X-ray diffraction patterns of Mg–Al₂O₃ composites with varying reinforcement contents. The diffraction peaks observed at 2θ ≈ 32.2°, 34.4°, 36.6°, and 57.0° correspond to the hexagonal close-packed (HCP) structure of α-Mg, which remains the dominant phase in all compositions. Characteristic peaks associated with Al₂O₃ are also observed, and their relative intensities increase with increasing Al₂O₃ content, confirming the presence of the ceramic reinforcement. No additional peaks corresponding to intermetallic compounds or reaction phases are detected within the resolution limits of the XRD technique, indicating that no significant chemical reaction occurred between Mg and Al₂O₃ during sintering. Minor peak broadening observed in some compositions may be attributed to microstrain and reduced crystallite size; however, detailed crystallite size analysis was not performed in this study.

Table 9 illustrates how the XRD technique was used to examine the crystalline phases of samples following heat treatment based on this crucial idea. By the results obtained from XRD patterns, the production of rough needle-like crystals increases as the Mg concentrations of this analysis grow to 38.72 in 2theta (deg), height as 2939(54), and factor as 1.37(7). Mg(70%) + Al₂O₃ (30%), Mg(80%) + Al₂O₃ (20%), and Mg(90%) + Al₂O₃ (10%) as reported in 31(6), 2939(54), and 837(29). Furthermore, it is noteworthy that in the case of the Al-Mg/2 weight% Al₂O₃composite, the Al₂O₃ particles are visible in the X-ray diffraction peak, but in other composites, they are visible at 2θ as 29.2°, which corresponds to the Al₂O₃phase. From this all samples test the XRD results having little difference, that is, 10 to 13%, their doses do not affect the original characteristics of Mg and Al2O3 in applications.

Table 9.

Sample results of XRD test.

Sample specimen	2-theta(deg)	d(ang.)	Height(counts)	FWHM(deg)	Int. I(counts deg)	Int. W(deg)	Asym. factor
Mg(60%) + Al2O3 (40%)	33.256 (3)	2.45 (5)	302 (6)	0.123 (2)	4.7 (6)	0.25 (6)	1.21 (3)
Mg(70%) + Al2O3 (30%)	34.539 (10)	2.594 (7)	31 (6)	0.11 (2)	4.3 (6)	0.14 (5)	5 (7)
Mg(80%) + Al2O3 (20%)	38.372 (2)	2.34394 (12)	2939 (54)	0.1551 (16)	562 (3)	0.191 (4)	1.37 (7)
Mg(90%) + Al2O3 (10%)	78.114 (3)	1.2225 (4)	837 (29)	0.167 (3)	179.7 (18)	0.215 (10)	1.12 (10)

EDX test results

Additionally, the components included in the Al₂O₃hybrid composite were identified by energy dispersive X-ray spectroscopy (EDX) analysis, as illustrated in Fig. 12a–d. The peaks in the EDX data verify the presence of magnesium, aluminium, and GMB elements (silicon and oxygen) in the Al-based hybrid composite.

Fig. 12.

EDXpatterns of Mg and Al₂O₃ composites.

The EDX chemical assessment data for the base material in the alumina-strengthened sample weld nugget are reported in Table 10. A silicon/silicon drift detector, which bases its measurement on area, was used to do the EDX measurement. MgK content was 47.0 in Mg(70%) + Al₂O₃ (30%), MgK content was 57.5 in Mg(60%) + Al₂O₃ (40%), and the greatest amount of AlK was 86.66 in Mg(80%) + Al₂O₃ (20%). Every sample underwent the measurements. The data points are dispersed over a wide range of values, as evidenced by the extremely high standard deviations for both the weight% and the at%. The chemical content of EDX study OK, AlK, MgK as the average value, as 9.66, 2.72, 86.66, 0.96, 28.0, 47.0, 25.0 in all samples, the normal parameter values reached in Mg(60%) + Al₂O₃(40%),is applicable for all engineering applications. Every analysis site underwent EDX analysis, and the elements present were measured both qualitatively and quantitatively. Each element’s weight fraction in the spectrum was determined. The weight percentages of the various elements were also determined after normalization to 100% for magnesium.

Table 10.

EDX Results.

Sample specimen	Element	Weight (%)	Atomic (%)	Error (%)	Kratio
Mg(90%) + Al2O3 (10%)	OK	34.4	45.8	7.4	0.1446
	MgK	26.1	22.9	4.3	0.1808
	AIK	39.6	31.3	5.8	0.205
Mg(80%) + Al2O3 (20%)	OK	2.72	4.06	4.8	0.185
	MgK	86.66	76.56	4.9	0.123
	AIK	0.96	0.21	7.6	0.23
Mg(70%) + Al2O3 (30%)	OK	28.0	38.0	7.4	0.1193
	MgK	47.0	41.9	3.7	0.3482
	AIK	25.0	20.1	7.2	0.1011
Mg(60%) + Al2O3 (40%)	OK	25.5	34.7	7.4	0.1096
	MgK	57.5	51.5	3.4	0.4373
	AIK	17.1	13.8	7.9	0.0616

The observed trend through enhancement of mechanical properties of the Mg- Al₂ O₃ composites with increment in the amount of Al ₂ O₃ can be explained by a series of concurrent strengthening mechanisms. One, the hard ceramic Al₂ O₃ particles enable effective transfer of the loads between the softer magnesium matrix to the reinforcement phase, therefore, enhancing the ability of the composite to resist compressive influence in load. Second, the particles of Al₂ O₃ have the effect of inhibiting the movement of dislocations, resulting in a higher density of dislocations and a higher plastic deformation resistance. Moreover, the homogeneous distribution of particles of Al₂ O₃ at lower reinforcement levels leads to refinement of the microstructures and localised deformation decreases, which leads to hardness. The thermal expansion mismatch between magnesium and Al₂O₃ may also introduce geometrically necessary dislocations during cooling, further contributing to strengthening. At higher Al₂O₃ contents, however, particle agglomeration and increased porosity reduce the effectiveness of these mechanisms. Agglomerated particles act as stress concentrators and weaken interfacial bonding, which explains the observed reduction in compressive strength and hardness at 40 wt% Al₂O₃.

Conclusion

In the current paper, composites of Mg- Al ₂ O ₃ were commonly prepared between powder metallurgy approach wherein powder preyed upon blending, cold compaction, sintering in an argon environment, and post-sintering extrusion.The experimental results indicate that the addition of Al₂O₃ reinforcement significantly influences the mechanical and tribological behavior of magnesium. Compressive strength and hardness increase with increasing Al₂O₃ content up to 30 wt%, reaching maximum values of approximately 204 MPa and 66 HV, respectively. A further increase in reinforcement content to 40 wt% results in a reduction in these properties, which is attributed to particle agglomeration, interfacial debonding, and increased porosity. Wear test results reveal that the composite containing 10 wt% Al₂O₃ exhibits the lowest wear rate under the tested conditions, while higher reinforcement levels lead to increased wear due to third-body abrasion effects. Microstructural analysis ensures the distribution of Al₂ O₃ particles in the Mg matrix and substantiates the trends of observed qualities.Overall, the study demonstrates that an optimal Al₂O₃ content exists for balancing strength, hardness, and wear resistance in Mg-based composites fabricated via powder metallurgy. The findings are limited to laboratory-scale conditions, and further investigations are required to evaluate performance under application-specific environments.

Author contributions

M.K.: Writing- original draft, investigation, methodology. M.A.:- Writing- review & editing, conceptualization, data curation.

Funding

No funding is involved in this work.

Data availability

The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.

Competing interests

The authors declare no competing interests.