DSC TRANSFORMATION BEHAVIOR OF A BCC MG11SM PHASE PREPARED BY RAPID SOLIDIFICATION

The transformation behaviour of the bcc Mg11Sm phase prepared by rapid solidification from the melt has been studied by DSC. The Kissinger and Ozawa equations led to the following activation energies of the first and the second phase transition: E almost-equal-to 130 kJ/mol and E almost-equal-to 194 kJ/mol, respectively. Isothermal Avrami kinetics of the first phase transition starts with an Avrami exponent n almost-equal-to 2,5, dropping down at higher degrees of transformation to n almost-equal-to 1.5. The data obtained have been compared with the parameters of the isothermal Avrami kinetics of decomposition of a rapidly quenched supersaturated MgYb4.8.7 alloy.