Cu-9.5Ni-2.3Sn-0.2Si合金铸态组织与时效性能的研究

应用金相显微镜、能谱仪、X-射线衍射仪、SIGMASCOPE SMP10型导电仪、维氏硬度计等仪器,分析了添加0.2％(质量分数)Si对C72500合金的铸态微观组织、时效后的微观组织、电导率和硬度的影响.结果表明:向C72500合金中添加0.2％Si后,合金铸态组织呈明显的树枝晶状,且枝晶发达,组织中出现了Ni2Si、NiSn、Ni3Sn相,经400℃×4h时效后,由于Ni2Si、Ni3Si相的析出,通过阻碍晶粒长大和时效沉淀而强化.合金的电导率随时效时间的延长或时效温度的提高一直增大,随后增加减缓,而合金的硬度与时效时间、时效温度曲线是单峰曲线,并随时效时间的延长或时效温度的提高先增大后减小,合金时效制度以400℃×6h为宜.

Study of As-Cast Structures and Aging Treatment Properties of the Cu-9.5Ni-2.3Sn-0.2Si Alloy

Researches in the effects of adding 0.2% Si to the C72500 alloy are carried out by applying testing instruments such as a metallographic optical microscope,EDS Miniflex X-ray diffraction,a SIGMASCOPE SMP10-type conductivity meter,and a Vickers hardness tester.The as-cast microstructures,aging treatment properties,conductivity,and hardness of the Cu-9.5Ni-2.3Sn-0.2Si alloy are studied.With 0.2% Si added,the dendrite structure becomes obvious and the Ni2Si,NiSn,and Ni3Sn phases are observed in the as-cast structures of the alloy.After 400℃×4h aging treatment,the alloy is strengthened due to the formation of the new Ni2Si and Ni3Si phases which interrupt the growth of the grains and the aging deposition.The conductivity increases while the increasing rate slows down with increasing aging time and temperature.The hardness of the alloy increases with the aging time and temperature at first,then decreases after reaching the peak.The optimal aging treatment for the alloy is found to be at 400℃×6 h.