Thermal and Huang diffuse scattering by shape-memory alloy martensites

Abstract

Many shape-memory alloy martensites exhibit tweed microstructures and diffuse diffraction similar to the cubic parent phases. The results of kinematic calculations of the distribution of thermal and Huang diffuse scattering in reciprocal space are presented for tetragonal and orthorhombic crystals. Comparisons with experimental observations of the diffuse diffraction from tetragonal nickel—aluminium martensite indicates that the diffuse intensity arises from tetragonal elastic distortion of the lattice due to nickel atoms in excess of stoichiometry.