Structure Parameters of the Au–49.5 at%Cd Martensite at Various Temperatures Approaching the Reverse Transformation Temperature A_s

Abstract

Precursor phenomenon on the martensitic transformation was studied in Au_50.5Cd_49.5. For the precursor study, single variant of ζ₂′ martensite was produced and the reverse transformation process was utilized to avoid a superposition of several variants in diffraction experiments through the martensitic transformation, i.e. from parent to martensite phase. Atomic parameters in martensite state were refined with use of single crystal structure determination procedure by X-ray at various temperatures approaching the reverse transformation temperature. Atomic positional parameters of some atoms which are expected to have relatively large displacements from parent phase showed first-order feature.