摘要
Mechanical properties of aluminum−silicon−copper alloys are enhanced through precipitation hardening.The response of these alloys to age-hardening is very slow.To overcome this problem,0.2,0.4 and 0.7 wt.%magnesium were added to Al−10.5Si−3.4Cu alloy.The new alloys were subjected to two types of precipitation hardening processes different in the solutionizing stage.The results showed that the presence of various amounts of magnesium in the composition of this alloy accelerates the response to ageing treatments,increasing the hardness and strength.Higher mechanical properties can be achieved when the alloys were subjected to a two-stage solution heat treatment.It is found that Al−10.5Si−3.4Cu alloy containing 0.2 wt.%Mg treated through a two-stage solution process,has optimum properties with ultimate tensile strength of 383.9 MPa,yield strength of 289.7 MPa and elongation of 3.97%,and can be used as a substitute for a large number of aluminum castings which need high strength and excellent castability.
通过析出硬化提高Al−Si−Cu合金的力学性能。这些合金对时效硬化的反应非常缓慢。为了解决这一问题,在Al−10.5Si−3.4Cu合金中分别加入0.2%、0.4%和0.7%(质量分数)的镁。该新型合金在固溶处理阶段经过两种不同的析出硬化过程。结果表明,添加不同含量的镁可加速该合金对时效处理的响应,提高其硬度和强度。双级固溶热处理可以提高合金的力学性能。添加0.2%Mg的Al−10.5Si−3.4Cu合金通过双级固溶热处理后获得最佳的性能,其极限抗拉强度为383.9 MPa,屈服强度为289.7 MPa,伸长率为3.97%,可替代需要高强度和优良铸造性能的铝铸件。
