A356铝合金轮毂挤压铸造的不均质性模拟及验证

Simulation and Verification of Inhomogeneity in A356 Wheel Hub Prepare by Squeeze Casting

对挤压铸造A356铝合金汽车轮毂进行了模拟。根据轮毂不同位置的凝固时间,分析得出了轮毂不同位置的凝固方式,并试验研究了挤压铸造下轮毂不同位置的组织不均匀性。得出轮毂不同位置的组织与凝固方式的关系:急冷区的凝固方式为逐层凝固,晶粒尺寸与组织分布较为均匀;压力结晶区的凝固方式为同时凝固,组织分布均匀,晶粒圆整;急冷区和压力结晶区之间的区域的凝固方式属于糊状凝固,晶粒尺寸与组织分布不均匀,共晶Si大量偏聚在晶界处。

Filling and solidification of A356 wheel hub were simulated by numerical simulation.According to the solidification time and temperature at different positions of the wheel hub,solidification modes of different position at the aluminum alloy hub were described,and the inhomogeneity of microstructure at the different solidification modes was described.The results reveal that the alloy is solidified in the way of layer-to-layer in the quenching zone,where grain size and microstructure exhibit homogenous,and in the zone of pressure crystallization solidification zone,the alloy is solidified in the way of simultaneous solidification,where the microstructure exhibits homogeneous distribution with round particles.In the transient zone between quenched and pressure crystallization,the alloy is solidified in the way of pastesolidification,so grain size and microstructure exhibit heterogeneous with obvious segregation of eutectic Si in the grain boundary.