【摘要】 开展了新型Al-Mg-Si免热处理铝合金挤压铸造凝固组织数值模拟。宏观数值模拟结果表明：变截面铸件的凝固顺序为中下部—中上部—顶部—底部；随着浇注温度、模具温度的升高，缩松体积分数先减小后增大，当浇注温度700℃、模具温度475℃时，缩松体积分数最小；随着挤压铸造压力的增大，缩松体积分数降低，在100 MPa时，缩松体积分数最小。微观组织数值模拟结果表明，铸件底部和中上部组织较为粗大，中下部和顶部组织较为细小，这与壁厚和过冷度有关。更多还原

【Abstract】 Numerical investigation on solidification microstructure of a new-type non-heat-treated Al-Mg-Si aluminum alloy during squeeze casting was carried out. The results of macroscopic numerical simulation show that the solidification sequence of the casting with variable cross-section is middle lower part, middle upper part, top part and bottom part; with the increase of pouring temperature or mold temperature, shrinkage volume fraction firstly decreases and then increases, and when the pouring temperature is 700 ℃ and the mold temperature is 475 ℃, the shrinkage volume fraction is the smallest; with the increase of squeeze casting pressure, the shrinkage volume fraction decreases, and the shrinkage volume fraction is the smallest at 100 MPa. The microstructure numerical simulation results show that the microstructure at the bottom and middle and upper parts of the casting are coarser, and smaller at the middle and lower parts and top parts, which is related to the wall thickness and the degree of supercooling.更多还原