The explosive crystallization process in binary amorphous alloys Ni-Zr system

A series of theoretical calculations have been carried out to analyze the possibility of the explosive crystallization process under laser treatment of binary amorphous alloys based on the Ni-Zr system. The characteristics of the crystallization process were calculated for two cases: slow heating of amorphous specimen with speed 0,16 K/s and an instant laser pulse, and heating of amorphous specimen by a laser beam to a certain temperature within 10
^-6
seconds. The high heating rates, achieved by the laser treatment of amorphous alloys, create a number of differences in the course of crystallization processes compared with crystallization during slow isothermal annealing. According to the calculations for Ni64Zr36 alloy, impulse heating to temperatures below 525 K does not cause crystallization. After 526 K there are significant changes in the kinetics of crystallization. At 527 K, the crystalline phase part has reached the value 8%. In the interval from 527 K to 528 K there is a sharp jump in the value of the crystal phase proportion from 8% to 97%, that is, a complete crystallization of the amorphous alloy occurs. In this way it is shown that under laser annealing in binary amorphous alloy based on Ni-Zr system there can be a phenomenon of explosive crystallization at a temperature which is 70 K lower than the temperature of the intensive crystallization beginning at slow heating.