时效工艺对含微量钪和锆2023铝合金组织和力学性能的影响

摘要

采用显微硬度仪、拉伸试验机、光学显微镜和透射电镜等方法研究了不同时效工艺对含有微量元素钪和锆2023铝合金组织和力学性能的影响.结果表明:2023铝合金在T8峰时效态下的硬度、抗拉强度以及屈服强度分别比T6峰时效态下的高25HV、37 MPa、108 MPa,但伸长率降低了67％；钪和锆的添加能使合金中形成细小弥散分布的Al3 Sc1-xZrx粒子,促进S’相均匀而细小地析出,该粒子能有效钉扎位错,细化晶粒,抑制再结晶和晶粒长大,使合金获得较少的再结晶组织；微量钪和锆能加快合金在T6状态下的时效响应速度,提高其时效硬化能力,并改善合金的强度和塑性；但是在T8状态下,随着位错的大量引入,钪和锆的这些作用被减弱.%The effects of different ageing processes on microstructure and mechanical properties of 2023aluminum alloy containing trace addition of Sc and Zr were studied by microhardness testing,tensile testing,optical microscopy and transmission electron microscopy.The results show that the hardness,tensile strength and yield strength of the 2023 alloy in T8 peak ageing state were higher than those in T6 peak ageing state by 25 HV,37 MPa and 108 MPa,respectively,but the elongation of the alloy decreased by 67％.With the addition of Sc and Zr,fine and dispersed Al3 (Sc1-x Zrx)particles precipitated in the alloy,and thus to promote S' phase precipitation with homogeneous and small grains.The Al3 (SC1-xZrx)particles could pin the dislocations and refine grains,also inhibit the recrystallization and growth of the grains,so the alloy obtained the microstructure with fairy few of recrystallization.Trace addition of Sc and Zr could accelerate the ageing responce rate of the alloy in T6 state,increase its ageing harding performance and promote the strength and plasticity of the alloy.But the effects of SC and Zr were weakened in T8 state because a lot of dislocations were introduced in that state.