Low-temperature structure transformation in In–Cd solid solutions

In the temperature range from 6 to 300 K, the resistivity ρ, microhardness HV, dynamic Young’s modulus E and logarithmic decrement δ (vibration frequency ∼75 kHz) have been studied in In–4.3 at.% Cd polycrystalline alloy. The measurements were carried out during cooling and heating of samples at a rate of 1 K min−1. A hysteresis with boundaries Tmin≅150 K and Tmax≅290 K is observed in the temperature dependences ρ(T), E(T) and δ(T). The maximum relative values of the hysteresis loops are Δρ/ρ≅0.1, ΔE/E≅0.25 and Δδ/δ≅0.25. Within the hysteresis region, the characteristics measured are unstable and their values change slowly with time at fixed temperatures. The hysteresis has not been registered in HV(T), but the derivative d/dT Hv(T) has an essential feature in the temperature interval Tmin<T<Tmax. The anomalies mentioned are indicative of the existence of some low-temperature structural transformation of hysteretic type controlled by complicated kinetics with large relaxation times. The structure and the physical and mechanical properties of pure In remain stable in the temperature range studied and reveal no anomalies mentioned. It is also shown that the alloy In–4.3 at.% Cd has sufficiently high plastic compliance and internal friction in a wide range of low temperatures that qualify it as a high damping material.