挤压铸造Al-5.0Cu-0.8Mg-0.5Fe合金的组织及性能

Microstructures Evolution and Mechanical Properties of Squeeze Cast Al-5.0Cu-0.8Mg-0.5Fe Alloys

采用金相组织观察、扫描电镜、拉伸性能测试等手段,研究了挤压铸造Al-5.0Cu-0.8Mg-0.5Fe合金的组织演变和力学性能。结果表明,当挤压压力从0增大到75 MPa时,合金的力学性能得到显著提高,这主要是由于挤压压力有利于Al-Cu合金中汉字状AlmFe相的形成,抑制针状β-Fe相的形成,同时显著细化富Fe相,减少铸造缺陷。当挤压压力为75MPa时,铸态下合金抗拉强度为258 MPa,伸长率为8.5%,经T6热处理后,其抗拉强度为432 MPa,伸长率为6.7%。

The microstructures evolution and mechanical properties of squeeze cast Al-5.0Cu-0.8Mg-0.5Fe alloys were investigated by metallographic microstructure observation,scanning electron microscopy,tensile testing.The results reveal that the tensile properties of Al-Cu alloy containing high Fe content are improved greatly with the applied pressure increasing from 0to 75 MPa,which are attributed to the applied pressure promoting the formation of Chinese script AlmFe and preventing the precipitation of needle-likeβ-Fe,refining Fe-rich intermetallics as well as decreasing cast defects.With the applied pressure of 75 MPa,the tensile strength and elongation of the alloy reach 258 MPa and 8.5%in as-cast condition,while they reach 432 MPa and 6.7% after T6 heat treatment,respectively.