半固态流变压铸AlSi10MnMg合金组织和热处理工艺试验研究

Experimental study on microstructure of Al Si10MnMg alloy formed by semi-solid rheo-diecasting and heat treatment process

采用金相显微镜和电子拉伸机,研究了Al Si10MnMg合金半固态流变压铸成型件的组织及热处理工艺。结果表明:半固态流变压铸件的组织致密,表面平整无明显铸造缺陷,有大量共晶组织聚集,局部出现偏析现象。较好的固溶热处理制度为520℃2 h,时效热处理制度为220℃3 h,共晶硅能在最短时间内迅速发生颈缩、枝晶熔断、共晶硅粒球化,Si相的回溶程度高,时效处理中析出的Mg2Si多,此时,屈服强度可达178.6 N/mm^2,抗拉强度为198.6N/mm^2,伸长率为6.9%,高于常规压铸件的。

The microstructure and heat treatment process of AlSi10 MnMg alloy parts formed by semi-solid rheo-diecasting were studied by means of metallographic microscope and electronic drawing machine.The resulted diecasting parts show dense structure,flat surface,no obvious casting defects,aggregation of many eutectic structures,and also local segregation.The better solution heat treatment system is 520℃2 h and the aging heat treatment system is 220℃3 h.Under these conditions,eutectic silicon can be necking,dendrite melting and eutectic silicon spheroidizing in the shortest time.The Si phase shows a high degree of redissolution and much Mg2 Si is precipitated in aging treatment.At this time,yield strength,tensile strength,and elongation are 178.6 N/mm^2,198.6 N/mm^2,and 6.9%,respectively,which are higher than those of conventional die-casting.