Zr+Er及Zr+Y对Al-Mg-Si-Cu-Mn-Cr合金组织和拉伸力学性能的影响

采用光学显微镜(OM)、电子显微镜(SEM)、能谱分析仪(EDS)、透射电子显微镜(TEM)和拉伸强度试验研究了0.3%Zr+0.2%Er和0.3%Zr+0.2%Y(质量分数)两种元素组合对Al-0.6Mg-0.9Si-0.5Cu-0.5Mn-0.2Cr合金热处理前后微观组织和力学性能的影响。研究结果表明,两种元素组合的加入均能细化铸态晶粒,其中Zr+Y改性合金的晶粒细化更明显,且两种改性合金铸态的强度和塑性均较基体合金提高。在热处理过程中,两种元素组合会影响合金中弥散相的析出,降低合金的弥散强化效果。最终,Zr+Er改性合金的强度较基体合金提高,而Zr+Y改性合金的强度则较基体降低,两种合金的塑性均较基体降低。

Effects of Zr+Er and Zr+Y on Microstructure and Tensile Properties of Al-Mg-Si-Cu-Mn-Cr Alloys

The effects of 0.3％Zr+0.2％Er and 0.3％Zr+0.2％Y (mass fraction) on the microstructure and mechanical properties of Al-0.6Mg-0.9Si-0.5Cu-0.5Mn-0.2Cr (mass fraction) alloy before and after heat treatment were investigated based on optical microscopy (OM),scanning electron microscopy (SEM),energy-dispersive X-ray spectrometry (EDS),transmission electron microscopy (TEM) and tensile test.The results showed that both Zr+Er and Zr+Y could refine the a-Al grains,and the latter was more prominent and effective.Furthermore,both of them could improve the strength and ductility of the as-cast Al-0.6Mg0.9Si-0.5Cu-0.5Mn-0.2Cr alloy.With heat treatment,both Zr+Er and Zr+Y had a negative influence on the precipitation of dispersed phase in the alloy and resulted in a decrease in dispersion strengthening.Finally,Zr+ Er modified alloy had higher strength than matrix alloy,while Zr+Y modified alloy had lower strength,and both of them had lower elongation than matrix alloy.