Effect Of Scandium On Microstructure And Mechanical Properties Of 6061 Aluminum Alloy

6061 alloy have been widely used in automobile,aerospace,architectural decoration and other industrial fields due to its medium strength,excellent performance of processing and corrosion resistance.For 6×××alloys,thermal-compression and T6 heat treatment is a frenquently process way to use.And the rare earth element Sc has been considered as the most efficient micro-alloying element in the aluminum alloy.In this paper,Sc added in6061 cast alloy to investigate the effect of Sc on microstructure and mechanical properties of 6061 alloy during the machining process.In this work,6061 cast alloys with different contents of Sc addition were prepared by melting and casting techniques.Thenthe influence of Sc on microstructure and performance of 6061 alloys were studied and the optimum adding amount of Sc was determined.Further more,the effects of Sc on homogenization,thermalcompression,solid solution and artificial aging treatment was studied.XRD,OM,SEM,EDS were assisted in the research.The main conclusions are listed as follows:The researches show that add 0.2 wt.%Sc to 6061 aluminum alloys have good comprehensive mechanical properties.As a result,the tensile or yield strength and elongation has increased by 11.34%,21.5%and 56.81%,respectively.The Fe-phase in the6061 alloy after homogenization had been transformed form?-AlFeSi to?-AlFeSi,and exhibited two shapes of particles.Sc additives in 6061 alloy can separate out more Mg₂Si phase to inhibit the recrystallization process under the equal conditions by hot compression.The tensile or yield strength has increased by 2%and 7.9%.The 6061 alloy contained Sc after heat treatment had lower value on tensile or yield strength and elongation.This is because Si and Sc generate the V-phase?AlSc₂Si₂?.V-phase?AlSc₂Si₂?lead the Sc atoms and Si atoms in 6061 alloy decreased,thus the number of?"-phase decreased,and the performance depreciation.