热处理工艺对含Er压铸Al-Si-Mg合金组织及性能的影响

Effect of heat treatment processes on microstructure and properties of die-cast Al-Si-Mg alloy containing Er

以含Er的压铸Al-Si-Mg合金为研究对象,通过拉伸性能测试、光学显微镜(OM)、扫描电镜(SEM)、能谱(EDS)及透射电镜(TEM)分析及定量统计,分析研究了不同固溶、时效工艺对合金组织及性能的影响。结果表明:双级固溶有利于一次相回溶至基体,使合金的塑性提高;固溶温度、时间的提高能够增加固溶到基体中的溶质原子和一次相的数量。Al-Si-Mg合金峰时效时,主要的强化相为β″、β'相,β'相主要表现为长条状及"T"字形。当热处理工艺为(280℃×3 h+530℃×3 h)固溶+170℃×3 h时效时,合金的伸长率达8.5%,具有高塑性;热处理工艺为(280℃×3 h+540℃×10 h)固溶+170℃×10 h时效时,合金的抗拉强度为344 MPa,屈服强度为312 MPa,合金具有高强度。

Effects of different solid solution treatments and aging processes on the microstructure and mechanical properties of die-cast Al-SiMg alloy containing Er were studied by using tensile test,optical metallographic microscope,scanning electron microscope(SEM),energy spectrum(EDS)and transmission electron microscope(TEM)analyses and quantitative statistics.The results show that the two-stage solid solution treatment is beneficial for the primary phase to dissolve back into the matrix and improve the plasticity of the alloy.The increase of solution treatment temperature and time can increase the number of solute atoms and primary phases dissolved in the matrix.In the alloy,the main strengthening phases during peak aging areβ″andβ’,and theβ’phase mainly exhibits strip shape and T-shape.When the heat treatment process is(280℃×3 h+530℃×3 h)solid solution treatment+170℃×3 h aging,the alloy has the elongation of 8.5%and shows high plasticity.When the heat treatment process is(280℃×3 h+540℃×10 h)solid solution treatment+170℃×10 h aging,the alloy has high strengths of which the tensile strength is 344 MPa and the yield strength is 312 MPa.