Synergistic Effect of Nanoscale Dispersoids and Submicrometer Grain Size on Superplasticity of Aluminum Alloys(Synergy by Microstructuring)

概要

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Examination of the superplastic behavior of two commercial aluminum alloys subjected to equal-channel angular extrusion showed that materials with an average grain size of 〜1.2μm can exhibit extraordinary superplastic ductility if an alloy contains a dispersion of nano-particles providing high stability of ultra-fine grained structure under static annealing and superplastic deformation. An Al-6%Mg-0.35%Sc alloy contains a distribution of coherent Al_3Sc dispersoids which exerts a high Zener drag force. As a result, the submicrometer scale grained structure is essentially stable under superplastic conditions and the alloy the highest elongation to failure of 2000% was attained at a temperature of 450℃ and an initial strain rate of 5.6x10^<-2> s^<-1>. In an Al-6%Cu-0.19%Zr alloy a low fraction of Al_3Zr particles could not prevent grain growth under high temperature, and this material showed marginal highest elongation of 375% at a temperature of 375℃ and a strain rate of 2.8x10^<-3> s^<-1>.
一般社団法人日本機械学会の論文
2006-09-19