压射速度和料饼厚度对压铸AM60B镁合金压室预结晶的影响

摘要

Standard mechanical test bars with a diameter of 6.4 mm and a gauge length of 50 mm were processed, and the microstructures of die cast AM60B alloy under different die casting process parameters were observed. The influences of the slow shot speed, the fast shot speed and the biscuit thickness on the externally solidified crystals (ESCs) were investigated. With the increase of the biscuit thickness, the number of the ESCs in the cast samples decreases. Under a low slow shot speed, larg ESCs are found in the cast structure and a high fast shot speed results in more spherical ESCs. The relationships between ESCs and process parameters were also discussed.%采用不同的慢压射速度、快压射速度和不同的料饼厚度,压铸直径6.4 mm、标距长度50 mm的标准拉伸试样,观察压铸试样的显微组织,分析不同工艺对压室预结晶的影响,讨论压室预结晶与工艺参数的关系.结果表明:随着料饼厚度的增加,组织中的压室预结晶数量减少:低的慢压射速度可获得较大尺寸的压室预结晶:高的快压射速度有利于形成球状的压室预结晶.