Ti、Sc、Zr联合添加对7005铝合金组织和性能的影响

Effects of Ti,Sc,Zr Joint Addition on Microstructure and Properties of 7005 Aluminum Alloy

利用光学显微镜、扫描电镜、硬度计、MTS810液压伺服试验机、EDS能谱仪等手段研究了Ti、Sc、Zr联合细化的7005铝合金变形前后的显微组织和性能。结果表明,Ti、Sc、Zr联合细化的7005铝合金具有最小的晶粒度,最优的力学性能,比细晶铝锭(GRAI)单独细化或者Sc、Zr联合细化的效果好,抗拉强度比国家标准提高了约24%,伸长率提高了55%。这是因为Ti、Sc、Zr联合细化的合金在凝固过程中形成了与基体共格的一次Al3(ScxZr1-x)和Al3(ScxTi1-x)粒子,起到了异质形核的作用,细化了合金晶粒尺寸。合金在均匀化和固溶时效处理后析出了大量弥散分布、热稳定性高并与基体共格的Al3(ScxZr1-x)粒子,提高了合金的硬度和强度。

Microstructure and properties of 70o5 aluminum alloy with Ti,Sc and Zr compound modification before and after deformation were investigated by optical microscope,scanning electron microscope,hardness tester,MTS810 servo hydraulic testing machine and EDS energy spectrometer.The results indicate that 7005 alloy modified by joint addition of Ti,Sc and Zr possesses the finest grain size as well as optimal strength,elongation,and electrical conductivity,which has better effects than those by single refine or Sc and Zr joint addition.The tensile strength and elongation of the alloy are increased by 24%and 55%than the national standards,respectively,which is mainly attributed to the formed primary Als(Sc,Zri-r)and Als(Sc,Ti-r)particles coherent with the matrix during solidification,playing a role of heterogeneous nucleation,thus refining the grain.Large amounts of dispersed Al,(Sc,Zri-)particles with high thermal stability are precipitated in alloy after homogenization and solution treatment,which is coherent with matrix,enhancing the hardness and strength.