A new method for evaluating the yield stress σ0.2 and the strain-hardening exponent n of metals is proposed through ultra-microhardness (UMH) technique with an application to fcc metals. UMH measurements with a triangular-base pyramidal indenter have been conducted on copper and copper-aluminum alloys under cold-rolled and annealed conditions at loads ranging from 0.05 g (4.9 × 10-2 mN) to 50 g (49 mN), and their results are compared with those of the Vickers hardness (Hv) at 200 g (1.96 N) and of tensile tests. The method is based on Cahoon et al.'s relation that σ0.2(MPa) = 3.27Hv (0.1)n and is composed of (i) the determination of the relationship between Hv and ultra-microhardness (Hum), (ii) the evaluation of n through analyzing the load dependence of Hum and (iii) the evaluation of σ0.2 from Cahoon et al.'s relation together with the results on (i) and (ii). The value of n can be extracted through the UMH test, and the value of σ0.2 evaluated from the present method, shows good coincidence with that obtained by tensile tests.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Materials Science(all)
- Nuclear Energy and Engineering