A KINETIC-STUDY ON THE SPONTANEOUS VITRIFICATION OF CR40TI60 ALLOY

Water-quenched Cr40Ti60, high temperature bcc solid solution, vitrifies on subsequent annealing, and vitrification is confirmed by X-ray and TEM. The kinetics of the vitrification behavior in this system are investigated by means of X-ray diffraction. For qualitative analysis, using X-ray diffraction intensity, the internal standard method is used. The activation energy for spontaneous vitrification (SV) is obtained on the basis of the Johnson-Mehl-Avrami equation: it is ∼ 46.6 kcal/mol. From DTA experiments, the measured activation energy for the equilibrium phase formation of the water-quenched β-phase is 62.0 kcal/mol. It is suggested that SV precedes the formation of quilibrium phases due to the activation energy difference between the vitrification and the equilibration. It is proposed that the mechanisms of SV is closely related to the diffusion of the Cr atom in the shore range, and consequently the lattice distortion due to the motion of Cr atoms results in the vitrification. © 1990.