上引连铸-连续挤压Cu-Cr-Zr合金的组织与性能

Microstructure and properties of continuous up-casting and CONFORMed Cu-Cr-Zr alloy

采用光学显微镜(OM)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM),观察了非真空上引连铸-连续挤压制备的大卷重Cu-Cr-Zr合金线杆的铸态、连续挤压态、固溶态和时效态的组织结构;通过力学、物理性能测试研究了各状态合金的性能变化规律。结果表明:上引连铸Cu-Cr-Zr合金线杆铸态为粗大柱状晶,存在CrSi2一次颗粒相;连续挤压后铸态柱状晶粒内部产生强烈的剪切变形,在TEM像中可观察到明显的位错塞积和缠结;连续挤压态合金线杆适宜的固溶处理温度范围为920~960℃,在大于980℃的固溶态组织中观察到孔洞缺陷;在正常固溶态组织中观察到粗大的Cr3Si颗粒相和纳米级含Zr的富Cr颗粒相,经选区电子衍射谱标定为Cr2Zr相;连续挤压线杆经(920℃,1 h)固溶+(60%的冷拉变形+时效+60%冷拉变形)后仍具有较好的综合性能,其抗拉强度为576 MPa,导电率为82%IACS。

The microstructures of an continuous up-casting and CONFORMed Cu-Cr-Zr alloy wire at up-casted,CONFORMed,aging and different solid solution treatment temperatures were investigated by optical microscopy(OM),field emission scanning electron microscopy(FESEM)and transmission electron microscopy(TEM).The physical and mechanical properties of the alloy at different deformation rates were tested.The results show that the as-casting grains are big columnar grains,CrSi2 particles are generated during the continuous up-casting.The grains of up-casted of the alloy are changed into the deformation structure with intense shear bands(SB)after CONFORM,the dislocation tangle and dislocation pile-up can be observed by TEM.The proper solid solution treatment temperature of the CONFORMed Cu-Cr-Zr alloy is in the range of 920−960℃.The microscopic holes are observed by SEM at matrix after solid solution treated over 980℃.The Cr3Si and Cr particles contained Zr exist in the matrix which solid solution treated at normal temperatures.Cr particles contained Zr are Cr2Zr phases determined by SADP.The better process of the alloy wire is solid solution treated at 920℃for 1 h+60%cold drawing+aging+60%cold drawing,and the tensile strength and electrical conductivity of the alloy wire are 576 MPa and 82%IACS,respectively.