Mg的添加及冷却方式对Cu-Cr-Zr合金组织与性能的影响

Effects of Mg addition and cooling methods on microstructure and properties of Cu-Cr-Zr alloys

采用真空感应熔炼制备Cu-Cr-Zr-Mg合金,研究Mg含量及冷却方式对Cu-Cr-Zr-Mg合金组织与性能的影响。结果表明:Cu-Cr-Zr-Mg合金铸态组织为α-Cu相和Cu-Cr共晶相所构成。随着Mg的添加,合金中二次枝晶臂间距明显减小,组织细化。经固溶时效处理后,纳米级CrCu_2(ZrMg)相从铜基体中析出,合金的硬度与导电率大幅度提升。当Mg含量为0.3%(质量分数)时,合金的综合性能最佳,硬度为138.3HB,导电率为79.1%IACS。与感应熔炼合金组织相比,采用铜模冷却的合金组织更加细小均匀,偏析少,经固溶时效处理后析出相尺寸明显减小,且析出相数量增多,合金的硬度和导电率分别达到156.8HB和82.8%IACS,合金抗拉强度达到451.8 MPa。

Cu-Cr-Zr-Mg alloys were prepared by vacuum induction melting method.The effects of Mg contents and cooling method on the microstructure and properties of Cu-Cr-Zr-Mg alloy were studied.The results show that the microstructure of as-cast Cu-Cr-Zr-Mg alloy isα-Cu phase and Cu-Cr eutectic structure.With the addition of Mg,the secondary dendrite arm spacing of the alloy decreases significantly and the microstructure is refined.After solution treatment and aging treatment,the nano-sized CrCu2(ZrMg)phase precipitates from the matrix,and the hardness and electrical conductivity of the alloy are greatly improved.When the Mg content is 0.3%(mass fraction),the alloy obtains the best overall performance,with the hardness of 138.3HB and the electrical conductivity of 79.1%IACS.Compared with the furnace cooling alloy,the structure of the alloy cooling in the copper mold is finer and more uniform,and the segregation is less.After the solution treatment,the precipitated phase size obviously decreases,and the number of precipitated phases increases.The hardness and electrical conductivity reach 156.8HB and 82.8%IACS,respectively,and the tensile strength reaches 451.8 MPa.