Precursor Phenomenon of Martensitic Transformation in Au-49.5at%Cd Alloy

Abstract

ABSTRACTPhonon softening was observed in the parent phase of a AuCd alloy which transforms from the β2(B2) parent to ζ2¹(trigonal) martensite. Since Cd strongly absorbs neutrons, the isotope 114Cd was used in preparing the single crystal for the measurements. The [ζζ0]TA2 phonon branch was measured and found to be anomalously low. A minimum is present at ζ=0.35 which softens with decreasing temperature towards Ms. The results are consistent with the model proposed by Ohba et al. based upon a crystallographic study of the ζ2¹ phase.