Figure 1. Compression flow curves with load direction being radial.

The compression tests were repeated at least five times. Insets represent the texture using {0002} pole figures (⊥ED). The texture of the materials is almost equivalent. Hence, texture effects are largely omitted in this study. According to the Hall–Petch relation, the FG material features higher yield strength; however, the CG material exhibits more pronounced work-hardening initially. (A–D) Strain levels for EBSD analysis, while the hexagon labels the strain level for serial sectioning analysis. ED, extrusion direction.