两步低温轧制与时效工艺对Cu-Cr-Zr-Hf合金组织和性能的影响

Structure and Properties of Cu-Cr-Zr-Hf Alloy by Two-Step Cryogenic Rolling and Aging Process

采用两步低温轧制与时效(CⅡ)工艺制备Cu-1Cr-0.2Zr-0.2Hf合金,利用电子背散射衍射(EBSD)、扫描电镜(SEM)等技术分析了该合金轧制态和时效态样品微观组织演变,同时测定其相应的抗拉强度和电导率,重点研究了两步低温轧制和最终时效对Cu-1Cr-0.2Zr-0.2Hf合金取向和性能的影响。结果表明,低温轧制促进该合金织构由铜型向黄铜型转变,形成黄铜型织构的主要原因是Copper型取向的晶粒发生孪生以及随后的滑移。最终时效处理不会改变轧制态样品的织构类型,只会影响其织构强度。两步低温轧制与时效工艺样品断口处有大量韧窝,断裂模式为典型的韧性断裂。两步低温轧制时效工艺制备出了具有抗拉强度为(642±2)MPa、电导率为(79.00±0.15)%IACS(国际退火铜标准)的高强高导Cu-1Cr-0.2Zr-0.2Hf合金,为制备高强高导铜合金提供了一种新策略。

Cu-1Cr-0.2Zr-0.2Hf alloy was systematically prepared using a two-step cryogenic rolling and aging process(CⅡ).The micro‐structure evolution of the as-rolled and aged samples of the alloy were thoroughly investigated through the electron backscattering dif‐fraction(EBSD),scanning electron microscopy(SEM)and so on.The corresponding ultimate tensile strength and electrical conductivity were determined at the same time.The effects of cryogenic treatment and final aging on the evolution of orientation and properties of Cu-1Cr-0.2Zr-0.2Hf alloy were emphasized.The results showed that cryogenic rolling promoted the transformation of the alloy texture from a Copper-type texture to a Brass-type texture,and the formation of the Brass-type texture originates from the twinning of grains with Copper orientation and the subsequent slip.The final aging treatment did not change the texture type of the as-rolled sample,only the strength of the texture.The fracture of the two-step cryogenic rolling and aging process(CⅡ)samples had a large number of dim‐ples and the fracture mode was typical of ductile fracture.The two-step cryogenic rolling and aging process prepared a high-strength and high-conductivity Cu-1Cr-0.2Zr-0.2Hf alloy with an ultimate tensile strength of 642±2 MPa and an electrical conductivity of 79.00±0.15%IACS(IACS:International Annealed Copper Standard),which provided a new strategy for the preparation of high-strength and high-conductivity copper alloys.