时效处理对Cu-3Ti-3Ni合金组织与性能的影响

Microstructural evolution and properties of the aged Cu-3Ti-3Ni alloy

摘要:

本文研究了时效处理对Cu-3Ti-3Ni合金组织与性能的影响。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)对Cu-3Ti-3Ni合金的组织和析出相进行了表征，并对其硬度、导电率和弹性模量进行了测试。结果表明：时效处理后析出Ni3Ti及 β'-Cu4Ti相。随着时效时间的延长，部分合金元素回溶于Cu基体，连续的亚稳定β'-Cu4Ti相向不连续的稳定Cu3Ti相转变。Ni3Ti相及β'-Cu4Ti相的析出减少了Ti原子的固溶，导致导电率升高。经过合适的时效处理，Cu-3Ti-3Ni合金中的Ni3Ti相及连续的亚稳定β'-Cu4Ti相析出完全，导致硬度升高，但时效处理对合金弹性模量影响不大。在本实验范围内，Cu-3Ti-3Ni合金的最佳时效处理工艺是 300°C时效2 h后炉冷，随后450 °C时效7 h炉冷。Cu-3Ti-3Ni合金的硬度、导电率及弹性模量分别是183 HV、31.34 % IACS (国际退火铜标准)及148.62 GPa。

Abstract:

The effect of aging treatment on the microstructure and properties of Cu-3Ti-3Ni alloy was studied. The microstructure and precipitated phase were characterized by X-ray diffractometer, scanning electron microscope and transmission electron microscope, and the hardness, electrical conductivity and elastic modulus were measured as well. The results show that a number of Ni3Ti and β'-Cu4Ti phase precipitate from the Cu matrix after aging treatment. With increase of secondary aging time, the partial alloying elements dissolve into the Cu matrix and the metastable Cu4Ti phase transform into incoherent equilibrium Cu3Ti phase. The enhanced electrical conductivity is ascribed to the decrease of Ti solubility in the Cu matrix by the formation of the Ni3Ti and β'-Cu4Ti precipitates. After an appropriate aging treatment of Cu-3Ti-3Ni alloy, the Ni3Ti and coherent metastable β'-Cu4Ti phase precipitate completely, giving rise to the increase of hardness. Aging treatment has no obvious effect on the elastic modulus of Cu-3Ti-3Ni alloy. In the range of the experiments, the optimal two-step aging treatment for Cu-3Ti-3Ni alloy is at 300°C for 2 h and 450 °C for 7 h. The hardness, electrical conductivity and elastic modulus are 183 HV, 31.34 %IACS (International Annealed Copper Standard) and 148.62 GPa, respectively.