时效处理对Cu-3Ti-3Ni合金组织与性能的影响（英文）

Microstructural Evolution and Properties of Aged Cu-3Ti-3Ni Alloy

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:Cu-3Ti-3Ni合金时效处理后析出Ni_3Ti及β'-Cu_4Ti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'-Cu_4Ti相向不连续的稳定Cu3Ti相转变。Ni_3Ti相及β'-Cu_4Ti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Ni_3Ti相及连续的亚稳定β'-Cu_4Ti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℃时效2 h后炉冷,随后450℃时效7 h炉冷。Cu-3Ti-3Ni合金的HV硬度、导电率及弹性模量分别是1.83 GPa、31.34%IACS(国际退火铜标准)及148.62 GPa。

The effect of aging treatment on the microstructure and the properties of Cu-3Ti-3Ni alloy was studied. The microstructure and the precipitated phase were characterized by X-ray diffractometer, scanning electron microscope and transmission electron microscope, and hardness, electrical conductivity and elastic modulus were measured as well. The results show that a number of Ni3Ti and β＇-Cu4Ti phases precipitate from the Cu matrix after aging treatment. With the increase of secondary aging time, partial alloying elements dissolve into the Cu matrix, and the metastable Cu4Ti phase transforms 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 phases 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 scope of the experiments, the optimal two-step aging treatment parameter for Cu-3Ti-3Ni alloy is to age at 300 °C for 2 h followed by aging at 450 °C for 7 h. The HV hardness, the electrical conductivity and elastic modulus are 1.83 GPa, 31.34 %IACS（International Annealed Copper Standard） and 148.62 GPa, respectively.