On the Martensitic Transformation in the Intermetallic System β′‐(Au, Pd)∼0.5Zn∼0.5

Abstract

AbstractThe martensitic phase transformation of alloys Au100−xZnx, 47 ⩽ x ⩽ 52, was studied in the temperature range 15 K ⩽ T ⩽ 100 K by measurements of the Hall coefficient RH, the specific electrical resistivity ρ, and by X‐ray powder diffraction. The influence of a third component on the martensitic transformation was investigated by replacing gold partially with palladium. A martensitic phase transformation was thereby found for the quasibinary section Au50−xZn50Pdx in the range 0 ⩽ x < 2.03. The Hall coefficient RH is very sensitive to the martensitic phase transformation in the systems Au100−xZnx and Au50−xZn50Pdx. – From X‐ray powder investigations on Au49.03Zn50.97 at T = 20 K, a hexagonal unit cell with a = (7.658 ± 0.003) Å, c = (5.476 ± 0.003) Å, c/a = 0.715 ± 0.006 was found and the atomic arrangement for this structure is proposed. Very small deformations are experienced by the cubic high temperature phase during transformation. The Bain distortion is discussed and compared with the distortion in the system Au100−xCdx. – The very similar mechanism of the martensitic phase transformation in Au100−xZnx and Au100−xCdx is discussed and a common dependence of the transformation temperatures for alloys Me1Me11 on the radii quotient r(Me1)/r(Me11) is proposed.