热处理工艺对AuCuAgZn17-7-1合金组织和硬度的影响

Effect of heat treatment process on microstructure and hardness of AuCuAgZn17-7-1 alloy

采用光学显微镜和显微硬度计对电刷用AuCuAgZn17-7-1合金在不同固溶和时效工艺下的显微组织、显微硬度进行测试和分析。结果表明:随着固溶温度的提高,晶粒度增大,670℃固溶保温30 min的试验合金的硬度显著低于原始材料,硬度均匀性提高,消除了触头零件边缘与心部硬度的差异性。合金在时效过程中析出第二相,随着时效温度的升高和保温时间的延长,第二相逐渐增大,硬度先上升后下降,存在明显的时效硬化现象。经670℃保温30 min固溶处理和250℃保温60 min时效后,合金达到峰值硬度,为311.5 HV0.2。

Microstructure and microhardness of Au Cu Ag Zn17-7-1 alloy for brush under different solution and aging processes were tested and analyzed by means of optical microscope,scanning electron microscope and microhardness tester.The results show that with the increase of solution temperature,the grain size is increased.The microhardness of the tested alloy after solution at 670℃for 30 min is significantly lower than that of the original material,and the microhardness uniformity is increased,which leads to elimination of the microhardness difference between the edge and the core of contact parts.The second phase is precipitated during aging process,and is gradually increased with the increase of aging temperature.The microhardness is increased first and then decreased,and there is obvious aging hardening effect.The peak-aging microhardness of the alloy is reached at 311.5 HV0.2 after solution treatment at 670℃for 30 min and aging treatment at250℃for 60 min.