Temperature insensitive negative Poisson's ratios in isotropic alloys near a morphotropic phase boundary

Poisson's ratio, shear modulus, and damping of polycrystalline indium-tin (In-Sn) alloys in the vicinity of the morphotropic gamma(γ)-gamma + beta(β) phase boundary were measured with resonant ultrasound spectroscopy. Negative Poisson's ratios were observed from 24 °C to 67 °C for alloys near the phase boundary. Properties were unaffected by annealing at 100 °C for 2 days. This isotropic fully dense negative Poisson's ratio material is temperature insensitive, in contrast to other materials that undergo phase transformation.