Zr含量及超声处理对Al-Zn-Mg-Cu合金组织及性能的影响

Effects of Zr Content and Ultrasonic Melt Treatment on Microstructure and Properties of Al-Zn-Mg-Cu Alloy

研究了不同Zr含量(0,0.1%,0.15%,0.2%,0.25%,质量分数)对Al-Zn-Mg-Cu合金组织及力学性能的影响,并对Zr含量为0.1%、0.25%的试样进行超声熔体处理,观察超声处理后试样的组织及性能变化。结果表明,Zr元素具有细化晶粒的作用,但随着Zr含量增加,成分偏析越严重,晶内第二相粒子数量增多,铸态试样抗拉强度先增加后降低,Zr含量为0.2%时达到峰值,而伸长率随着Zr含量增加不断下降。超声处理后,晶粒大小均匀,平均尺寸小于50μm,晶内第二相完全消除,成分偏析得到明显改善。

The effects of different Zr content(0,0.1%,0.15%,0.2%,0.25%)on the microstructure and mechanical properties of Al-Zn-Mg-Cu alloy were investigated.The alloy with Zr content of 0.1% and 0.25% was treated by ultrasonic melt treatment before pouring,and the microstructure and mechanical properties after ultrasonic treatment were analyzed.The results reveal that Zr can refine grain size,however,with Zr content increase,composition segregation is deteriorated,and the secondary phase is increased in the grain,resulting in the increase of firstly and then decrease of as-cast tensile strength with decrease of elongation.After ultrasonic melt treatment,the grains are refined with uniform distribution and average size less than 50μm,meanwhile,the second phase in the crystal disappears completely,and composition segregation is reduced significantly.