Effect Of Y On Microstructure And Mechanical Properties Of Mg-5Al-1Ca Magnesium Alloy

With the smooth convening of the 7th International Conference on Magnesium and Magnesium Alloys,the society is paying more and more attention to magnesium alloys.Mg-Al-Ca series magnesium alloys are widely used in automotive and aerospace fields because of their good high-temperature mechanical properties.This article starts from the perspective of preparing a high-strength and heat-resistant magnesium alloy.Mg-5Al-1Ca magnesium alloy is used as the base alloy,and different contents of Y are used as alloying elements.Through the use of optical microscope,SEM,XRD,TEM and other analysis tests Technology,research on as-cast,solid-solution,aging after solid-solution,and extruded Mg-5Al-1Ca-xY（x=0,0.5,1,1.5,2 wt.%）magnesium alloys,and developed A new type of high-strength and heat-resistant magnesium alloy.The study found that with the increase of Y content,the Al₂Y phase in the as-cast Mg-5Al-1Ca-xY magnesium alloy gradually increased,and the formation of Al₂Y phase would have a certain inhibitory effect on the formation ofβ-Mg₁₇Al₁₂and Al₂Ca phases.The addition of different content of Y will produce different degrees of refinement of the grain size of the as-cast Mg-5Al-1Ca-xY magnesium alloy,and with the increase of the Y content,the yield strength,tensile strength,and elongation of as-cast Mg-5Al-1Ca-xY magnesium alloy showed a trend of increasing first and then decreasing,and reached the best when the Y content was 1.5 wt.%,which were 126 MPa,181.6 MPa and 9.8%,respectively.After the as-cast Mg-5Al-1Ca-xY magnesium alloy is subjected to solution treatment and post-solution aging treatment,it is found that the as-cast Mg-5Al-1Ca-xY magnesium alloy is solid-solution treated at 420℃+10 h.The second phase of the molten alloy is significantly refined.After the solid solution alloy is subjected to the subsequent aging treatment at 200℃+24 h,the distribution of the second phase of each component alloy is more uniform.Through the forward extrusion of the Mg-5Al-1Ca-xY magnesium alloy in the solid solution and aging state at an extrusion ratio of 16:1,the mechanism of the effect of different contents of Y in the as-extruded Mg-5Al-1Ca-xY magnesium alloy was studied.Finally,an as-extruded Mg-5Al-1Ca-1.5Y magnesium alloy with higher strength was obtained.Then,through experimental research,the effect of tensile temperature and strain rate on the mechanical properties of as-extruded Mg-5Al-1Ca-1.5Y magnesium alloy was obtained,and the as-extruded Mg-5Al-1Ca-1.5Y magnesium alloy was analyzed aging hardening experiment,analysis and analysis obtained the best aging time of the as-extruded Mg-5Al-1Ca-1.5Y magnesium alloy is 48 h,which laid a theoretical foundation for the subsequent strengthening of the alloy.