The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of the metallic glasses. Two classes of the experimental data were chosen to draw the yield loci using the unified yield criterion. It is shown that the unified yield criterion can be used to describe the yield behavior of the metallic glasses no matter whether the metallic glasses show strength- different effect or non-strength-different effect. Almost all the widely accepted yield criteria are the subsets of the unified yield criterion if the intermediate principle stress and/or the intermediate principle shear stress are not considered at all.
The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated.The results show that the strengths of all the tested alloys with 0.1 wt.%,0.3 wt.%,and 0.4 wt.% Sc additions increase initially with an increase in annealing time,due to the increase in volume fraction and size and the decrease in particle interspacing of Al3Sc particles.After reaching peak values,the strengths of all the tested alloys start to decrease with increasing annealing time due to the coarsening and increase in particle interspacing of Al3Sc particles.It has also been shown that the alloy with 0.3 wt.% Sc has a higher strength and a lower elongation than the alloys with 0.1 wt.% and 0.4 wt.% Sc.The increase in strength and the decrease in elongation of the alloy with 0.3 wt.% Sc are due to the smaller particle interspacing of Al3Sc particles,resulting in a strong inhibition of dislocation movement during deformation.
SUN Yingying,SONG Min,and HE Yuehui State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China
