热处理工艺对低硅Al-Si-Mg铸造铝合金组织和力学性能的影响

Effect of Heat Treatment Processes on Microstructure and Mechanical Properties of Low-silicon Al-Si-Mg Cast Aluminum Alloy

对含3.47%Si、0.54%Mg、0.33%Cu和0.39%Cr(质量分数)的低硅Al-Si-Mg铸造铝合金进行了固溶处理和时效。固溶处理工艺:分别在510、520、530、540℃保温2、4、6和8 h水冷;时效温度为170、180、190℃,保温时间2、4、6和8 h。检测了合金的显微组织和力学性能。结果表明:该铸造铝合金的最佳热处理工艺为540℃×4 h水冷固溶处理,随后180℃×6 h时效处理,经此工艺热处理的低硅Al-Si-Mg铸造铝合金的抗拉强度为365.9 MPa,屈服强度为313.9 MPa,断后伸长率为9.3%。

Low-silicon Al-Si-Mg cast aluminum alloy,containing 3.47%Si,0.54%Mg,0.33%Cu,and 0.39%Cr by mass,was subjected to solution treatment consisting of holding at 510℃,520℃,530℃,and 540℃for 2 h,4 h,6 h and 8 h and cooling in water,then to aging at 170℃,180℃,190℃for 2 h,4 h,6 h and 8 h.After this,the alloy was tested for microstructure and mechanical properties.The results showed that the best heat treatment practices for the alloy were solution treatment at 540℃for 4 h and water-cooling,and aging treatment at 180℃for 6 h.After being heat treated in this manner the low-silicon Al-Si-Mg cast aluminum alloy offered tensile strength of 365.9 MPa,yield strength of 313.9 MPa,and elongation of 9.3%.