Effect of Sc and Zr on recrystallization behavior of 7075 aluminum alloy

Sc和Zr对7075铝合金再结晶行为的影响

The static recrystallization behavior of 7075 aluminum alloy containing Al_(3)(Sc,Zr)phase prepared by casting and the relationship between recrystallization behavior and mechanical properties were studied.The addition of Sc and Zr made the Sc−Zr−7075 aluminum alloy remain the most of fibrous structure and high-density dislocations formed in the extrusion process,resulting in the recrystallization fraction of the alloy decreasing from 35%to 22%,and the corresponding fraction of substructure increasing from 59%to 67%.The Sc and Zr effectively inhibited the recrystallization behavior of 7075 aluminum alloy mainly,which was attributed to the fact that the existence of fine and coherent Al_(3)(Sc,Zr)phase(r=35 nm,f=1.8×10^(−3))strongly pined the dislocations and grain boundaries,preventing the dislocations from rearranging into sub-grain boundaries and from developing into high angle grain boundaries,and further hindering the formation and growth of recrystallized core of the alloy.

研究通过铸造法制备的含Al_(3)(Sc,Zr)相的7075铝合金静态再结晶行为和再结晶行为与力学性能的关系。Sc和Zr复合添加使Sc−Zr−7075铝合金保留挤压变形过程中形成的大部分纤维组织及高密度位错,导致合金的再结晶转变量由35%降低至22%,相应的亚结构保持量由59%升高至67%。Sc和Zr有效抑制7075铝合金再结晶行为,这主要归因于细小弥散(r=35 nm,fv=1.8×10^(−3))的Al_(3)(Sc,Zr)相对位错和亚晶界具有强烈的钉扎作用,阻碍位错重新排列成亚晶界及随后发展成大角度晶界,进而阻碍合金再结晶核心的形成和长大。