Phase Transformations in Cd0.96Mn0.04Te0.98Se0.02 Solid Solutions

Abstract

We have studied phase transformations in Cd_0.96Mn_0.04Te_0.98Se_0.02 solid solutions in the temperature range of 1080-1149 °C using differential thermal analysis (DTA). Following the "heating-dwell-cooling" procedure, we investigated the melt supercooling versus superheating, crystallization temperature versus dwell temperature, and crystallization rate versus crystallization temperature. We observed that the Cd_0.96Mn_0.04Te_0.98Se_0.02 alloy remained in a semi-liquid state over the dwell temperature range of 1089-1097 °C. Following a "heating-dwell-heating-cooling" procedure, we investigated the solid-phase volume fraction versus dwell temperature, melting temperature versus dwell temperature and melt crystallization rate versus dwell temperature. We observed that at dwell temperatures higher than 1097 °C, the solid phase completely disappeared in the sample, since the effect of melting was not observed, meaning that the sample was a single-phase melt. Despite the fact that the alloy was heated in every cycle up to 1147 ± 2 °C after the intermediate dwell, structural fragments formed during this intermediate dwell were still present even at higher temperatures and, as a result, affected the crystallization. The range of crystallization temperatures decreases with increasing intermediate dwell temperature. Such dependence can be interpreted as an alloy “memory” of its thermal history.