Geometric parameters of iron-doped HA samples.

Samples (in % Fe doping)	Williamson Hall method						TEM (particle diameter in nm)
	UDM		USDM		UDEDM
	D (in nm)	Strain (ε)	D (in nm)	Stress (σ) (in TPa)	D (in nm)	Strain energy (μ) (in MJ m−3)
0	7.21	—	7.21	—	7.2	—	6
2	6.20	−0.75	6.01	−5.09	6.92	1.87	5.84
4	4.01	−1.72	5.61	−10.27	4.90	8.01	5.5
6	3.72	−1.92	5.16	−11.99	4.54	10.76	5.01
8	3.63	−2.03	5.03	−13.07	4.45	12.17	4.7
10	3.26	−2.34	4.40	−15.58	3.88	17.35	4.3