Thermal properties of Nichrome 5 -- a contribution to the understanding of kinetics of structural transitions

A study is presented of the structural transition in the Nichrome 5 alloy (80Ni-20Cr), more precisely of its dependence on the heating rate. The phenomenon was observed in the study reported at the 12th ECTP in Vienna, 1990 (Maglic et al, 1992 High Temp. -High Press. 24 165-173), when it was found that the transition may occur at a temperature approximately 150K higher than reported in the published literature. In contrast to the available literature data which were obtained by steady-state, or close to steady-state techniques, those measurements were carried out by a dynamic, millisecond-resolution pulse-heating technique, with heating rates ranging between 300 and 600 K s(-1). The new study reported here used also the pulse technique, and the heating rates ranged between 45 and 1800 K s(-1). The obtained dependence between applied heating rates and the shift in the transition temperature is not linear: the increase of the shift at higher heating rates becomes smaller. Results are presented and discussed.