The kinetics of crystallization have been examined in amorphous melt-spun $R_{50}$$T_{50}$ alloys with R=Nd,Tb and T=Fe,Co using the Kissinger method and the Johnson-Mehl-Avrami equation. The crystallization temperatures $T_{\mathrm{cr}}$ found were in the range of 192–493 °C with the Fe- and Nd-containing alloys having the higher $T_{\mathrm{cr}}$. The calculated activation energies were found to scale with the crystallization temperatures and were in the range of 1.61–2.48 eV. The Avrami exponent n obtained was in the range of 2.1–3.7 with the lower value occurring in ${\mathrm{Tb}}_{50}$${\mathrm{Fe}}_{50}$. In ${\mathrm{Nd}}_{50}$${\mathrm{Fe}}_{50}$, n=3, indicating a uniform three-dimensional growth.

• Received 1 March 1989

DOI:https://doi.org/10.1103/PhysRevB.40.5441