Study On Mechanical Properties Of Deformational Aluminum Alloy With Medium Strength And High Toughness

Al-Zn-Mg-Cu aluminum alloy is a popular research object for wheel hub lightweight.Microalloying and filtration are effective methods to improve the fatigue performance of aluminum alloys.In this study,three Al-Zn-Mg-Cu aluminum alloy substrates were used,Sc elements were added separately and Sc,Zr and Ce elements were added in combination.Ceramic foam filters were used in the pouring process.Unidirectional free forging was used after ingot homogenization,followed by recold rolling and cold forging after solid solution.After different aging processes,the influences of Sc elements on microstructure and mechanical properties of the alloy were mainly observed.The conclusions are as follows:?Compound Sc and Zr elements have better grain refining effect than Sc elements alone.This is mainly due to the formation of secondary Al3(Sc,Zr)phase particles with high symmetry structure,which can be used as heterogeneous nucleation core to refine the grain.?The mechanical properties of the alloy with added scandium and cerium are obviously lower than that with added scandium and cerium alone.?In the case of adding Zr,Cr composite,forged Sc element can significantly improve the strength of the alloy,11#Sc0.1 in the aging state of the best comprehensive mechanical properties,its tensile strength is 507.96MPa,yield strength 469.7MPa,elongation 8.9%,brinell hardness 130HBW.? Under the three different processes are Sc0.15 has higher strength than Sc0.1,but the elongation decline;The mechanical properties of 0.20%Sc alloy decreased seriously.? The alloy sample 14#with 0.1%scandium has the best comprehensive performance by forging direct solution aging process,and having highest elongation under heat treatment process of 120?×3h+160?×7h,an average of 8.8%,single test bar extension rate up to 9.4%.The performance of this process is already comparable to that of similar commercial hub materials,with the best plasticity.