2023 年 62 巻 1 号 p. 73-78
Rectangular–shaped bulky Cu–Be alloy was multi–directionally forged (MDFed) at ambient temperature. While coarse initial grains were gradually fragmented by mechanical twinning with increasing forging cumulative strain, grain fragmentation appeared more proceeded at surface–edge and inner–central regions than at surface–central and inner–edge ones of the MDFed sample. The hardness Hv, therefore, changed much depending on position from 2.69 GPa to 3.02 GPa at cumulative strain of ΣΔε=2.4. Hence, ultimate tensile strength (UTS) showed same tendency that the UTS at the inner–central region (962 MPa) was larger than that at the other regions (818 MPa), i.e., 15％ difference. Nevertheless, the difference in the UTS became much smaller to be 1.39 GPa at maximum and 1.32 GPa at minimum, i.e., 5％ difference, after peak aging at 513 K without showing large difference in the ductility around 4％, which should be due to the difference in the age–hardenability depending on microstructure.
