한국주조공학회

In this study, the authors experimentally investigated whether adding Cu, Mg, Mn, and Mo to a heat-treatable Al-Si alloy widely used in automotive parts would result in excellent mechanical properties even at relatively low solution heat treatment temperatures. Two different alloys, Al-7Si-0.5Cu-0.5Mg alloy (5M5C) and Al-7Si-0.5Cu-0.5Mg-0.3Mn-0.3Mo alloy (5M5C-MM), were solution heat-treated at various temperatures from 495 to 545ºC, followed by a microstructure analysis and hardness tests. After aging at 165ºC for eight hours, the tensile properties of the T6-treated alloys were also evaluated. The experimental results showed that both the hardness and the tensile strength of the alloys increased as the solution heat treatment temperature increased. The 5M5C-MM alloy showed enhanced hardness and tensile strength compared to the 5M5C alloy. Even after solution heat treatment at a low temperature of 515ºC, the T6-treated 5M5C-MM alloy showed high tensile strength of 376MPa and greater elongation than the 5M5C alloy. From the results of this study, it was confirmed that heat-treatable Al-Si aluminum alloys could be used in the production of large, thin-walled aluminum parts sensitive to thermal deformation by alloy design and a low-temperature solution heat treatment process.

알루미늄 합금, 용체화 열처리, 미세조직, 경도, 인장특성.