均匀化热处理改善铸态Cu-Ag合金各向异性研究

Improvement of Anisotropy of As-Cast Cu-Ag Alloy with Columnar Grains by Homogenization

对半连续铸造制备的Cu-Ag合金柱状晶区在不同温度下进行均匀化热处理,采用压缩变形并对Cu-Ag合金铸锭径向和垂直铸锭径向进行显微组织观察和抗拉强度、硬度测试,研究了均匀化热处理对铸态Cu-Ag合金柱状晶区塑性变形行为中各向异性的影响。结果表明：铸态Cu-Ag合金柱状晶区铸锭径向和垂直铸锭径向的塑性变形行为存在明显各向异性。Cu-Ag合金在铸锭径向有较高的弹性模量、室温抗拉强度和加工硬化率;而垂直铸锭径向的弹性模量、室温抗拉强度和加工硬化率较低。均匀化热处理后,Cu-Ag合金内部枝晶偏析等溶质分布不均匀性被消除,晶界趋于平直化,合金塑性变形行为中的各向异性减弱。

Semi-continuous casted Cu-Ag alloy with columnar grains was homogenized at different temperatures,and forging was introduced followed by microstructures characterization and tensile strength and hardness tests to investigate the anisotropy of as-cast and homogenized Cu-Ag alloy with columnar grains. The results showed that apparently anisotropy was observed in as-cast Cu-Ag alloy with columnar grains when deformed. Along radial direction,Cu-Ag alloy exhibited higher elasticity modulus,tensile strength and work hardening rate. While the elasticity modulus,room temperature tensile strength and work hardening rate were much lower in the direction perpendicular to axial direction of columnar grain. After homogenization,most dendrites and element segregation inside were eliminated and smooth grain boundaries were formatted,which led to the weakness of plastic anisotropy of Cu-Ag alloy.