The influence of Cd content on kinetics of the low-temperature structural transformation in In-Cd alloys

The influence of Cd content on the kinetics of spontaneous low-temperature structural transformation previously observed in the martensitic phase of the In-Cd solid solution has been investigated. In the temperature range 100-340 K, the acoustical, resistivity and calorimetric measurements were carried out on specimens containing 4.3, 5.5 and 6.6 at.% Cd. It is established that the transformation rate increases dramatically with increasing Cd content. The main empiric activation parameters of the transformation are obtained: the activation energy is U0 = 0.43 eV, the attempt period is τ0 =5·10-9s. It is shown that the transformation has the features typical of the 1-st order phase transition. It is supposed that the low-temperature isothermal instability of the macroscopic properties of the alloy is caused by the In-based solid solution decomposition. Essential increase of the decomposition rate with increasing Cd content may be due to an enhancement of the transformation driving force.