Studies On Copper Alloys Containing Chromium (2nd Report). On the Softening and Age-hardening of Copper Alloys Containing Chromium

Abstract

Samples of copper alloys containing chromium up to 1.02% were prepared by vacuum melting and casting with which the author studied the effects of chromium addition upon the softening temperature and mechanical properties at elevated temperatures, furthermore the effects of quenching temperatures, aging conditions and chromium addition upon the age-hardening. The results of the experiments were as follows: (1) The softening temperature of pure copper was about 200°, but of 0.10%Cr-Cu it was about 300°, and of 0.29∼1.02%Cr-Cu it was at about 400°. (2) To obtain better properties, the quenching must be done at proper temperatures, as follwos:
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(3) The aging temperature to obtain the maximum hardness and tensile strength, when the alloys were aged 1 hour, were about 520° and 480°. (4) At elevated temperatures, the tensile strength of 0.29%Cr-Cu was 3 to 4 times as large as that of pure copper.