Effect of Rare-Earth Er on the Microstructures and Tensile Properties of 1420 Al-Li Alloy
|School||Beijing University of Technology|
|Keywords||1420 Al-Li alloy REE Er Mechanical properties Microstructure Anisotropy|
Abstract The conventional ingot metallurgy prepared containing different amounts Er 1420Al-Li alloy , with a variety of test and analysis tools, the effects of different levels of Er on Al-Li alloys in different states ( cast , aged state ) the mechanical properties and microstructure of in-depth analysis of Er in the alloy form of existence , and the interaction of alloying elements , the alloy strengthening mechanism . Additionally, this article discusses the preliminary Er on Al-Li alloy anisotropy . The results showed that : Er content of less than 0.2%, the Al-Li alloy cast grain size is almost no effect when Er content of 0.2 % or more , the grain refining effect is very significant . Er different amounts in different degrees experimental alloys improve the aging state of the hardness and strength . When the content is 0.2% Er , Er can greatly improve the strength of the alloy ( 5 to 40% ) while the plasticity decreased slightly ; continue to improve Er content , strength without significantly improved but the plastic was more evident . Er on strengthening mechanisms alloys are mainly three kinds , namely the second phase precipitation hardening , grain refinement and substructure strengthening , where the former 's strengthening effect is large, the latter two strengthening effect is relatively small. Er element also can reduce the yield strength of Al-Li alloy anisotropy , mainly because of the added Er element of secondary Al3Er generated relative dislocation pinning to play a strong role in influencing the movement of dislocations , preventing a serious coplanar slip , thereby improving the uniformity of deformation of the alloy , reducing the anisotropy of the alloy . In short, the 1420 alloy is generated after adding rare earth elements Er Al3Er phase , this relative solidification nucleation , dislocation movement , anisotropy of the alloy will have a surface slip effect . The results show that , Er is the Al-Li alloy valid trace elements, add a 0.2% nominal composition Er, make experimental alloy has good overall performance.