Cu-20%Ni合金の主として機械的性質におよぼすBe, Cr添加の影響

Abstract

Following the previous work, the present study was undertaken for the purpose of obtaining the material having an excellent spring property and high corrosion resistance. Mechanical properties of Cu-20%Ni alloys containing various amounts of Be and Cr respectively, have mainly been investigated. These alloys were cast, hot-worked, solution-treated at various temperatures, cold-worked by 60∼90% to 0.5 mm thickness and subsequently aged at various temperatures for various times.The results obtained were as follows:(1) The properties in the aged state such as the spring or other mechanical properties of Cu-20%Ni alloys were sharply improved by adding a small amount of Be.(2) The alloy containing about 0.4%Be showed a maximum value of about 110 kg/mm2 in Kb, when it was solution-treated at 1050°C, quenched, cold-worked and then aged at 400°∼500°C for 1 hr. The values of Kb obtained for the alloys containing Cr amounted to about 70 kg/mm2 at most.(3) It was confirmed that the alloys containing Be and Cr were age-hardened due to the precipitation of NiBe (super lattice) and Cr, respectively. The mechanical properties of the alloys containing Be attained a maximum, when NiBe was in the state of G. P. plus intermediate phases.(4) The stress corrosion resistance of both alloys was much superior to that of nickel-silver.(5) From the above results, it has been concluded that the commercially available nickel-silver can be replaced by the alloys containing a small amount of Be.