La微合金化及温轧处理对Cu-Cr-Zr合金组织与性能的影响

Effect of La-microalloying and Warm Rolling on Microstructure and Properties of Cu-Cr-Zr Alloy

摘要:

Cu-Cr-Zr合金在通信电子、轨道交通和航空航天等领域应用较广，提升其强度和导电综合性能是近年来的研究热点。本工作设计和制备了Cu-1Cr-0.1Zr和Cu-1Cr-0.1Zr-0.069La合金铸锭，并对其进行了固溶-温轧-冷轧-预时效-冷轧-时效工艺处理。利用光学显微镜、扫描电镜和透射电镜对2种合金各状态宏微观组织进行了分析，利用显微硬度计、涡流金属导电仪对合金硬度和导电率进行了测试。结果表明：经过400 ℃温轧处理后，合金基体析出少量fcc结构纳米级Cr相，初生Cr相以球状和棒状形式分布在晶界和晶内，稀土La包裹在Cr相外层形成核壳结构，抑制了Cr相的长大。经过83%冷轧+ 400 ℃×2 h时效处理后，Cu-1Cr-0.1Zr-0.069La合金达到峰值硬度199.8 HV，此时导电率为66.5%IACS，较Cu-1Cr-0.1Zr合金峰值硬度提高20 HV，对应导电率降低3.5%IACS；进一步经过44%冷轧后，Cu-1Cr-0.1Zr-0.069La合金在400 ℃×4 h时效后达到峰值硬度为212.9 HV，抗拉强度为640 MPa，导电率为74.4%IACS，较Cu-1Cr-0.1Zr合金峰值硬度提高17.2 HV，导电率降低4.7%IACS。

Abstract:

Cu-Cr-Zr alloy is widely used in communication electronics, rail transit, aerospace and other fields, and improving its strength and conductive properties is a research focus in recent years. In this research, Cu-1Cr-0.1Zr and Cu-1Cr-0.1Zr-0.069La alloy ingots were designed and prepared, and treated by solution-warm rolling-cold rolling-preaging-cold rolling-aging processes. The macrostructure and microstructure of two alloys were analyzed by optical microscope, scanning electron microscope and transmission electron microscope. The hardness and conductivity of the alloys were measured by microhardness tester and eddy-current metal conductivity meter. The results show that after 400 ℃ warm rolling, a small amount of nanoscale Cr phase with fcc structure is precipitated from the alloy matrix. The primary Cr phases are distributed in spherical and rod-like forms at grain boundaries and within grains, and rare earth La is wrapped around the outer layer of Cr phase to form a core-shell structure, which inhibits the growth of Cr phase. After 83% cold rolling+400 ℃×2 h aging treatment, Cu-1Cr-0.1Zr-0.069La alloy reaches the peak hardness of 199.8 HV and the conductivity of 66.5%IACS, which is an increase in peak hardness of 20 HV and a decrease in conductivity of 3.5%IACS compared to Cu-1Cr-0.1Zr alloy. After further 44% cold rolling, Cu-1Cr-0.1Zr-0.069La alloy reaches the peak hardness of 212.9 HV, tensile strength of 640 MPa and the conductivity of 74.4%IACS after aging at 400 ℃ for 4 h. The peak hardness of Cu-1Cr-0.1Zr-0.069La alloy is 17.2 HV higher than that of Cu-1Cr-0.1Zr alloy, and the conductivity is decreased by 4.7%IACS.