| Title |
Discussion on the Johnson - Mehl - Avrami Equation Applied to the Crystallization Procedure of Metallic Glass |
| Authors |
김성균(Seong Gyoon Kim); 나형용(Hyung Yong Ra) |
| Abstract |
By modifing Johnson-Mehl-Avrami equation applicable to the isothermal phase transformation of space-random nucleation and constant growth rate, the time dependent nucleation rate could be expressed as a function of the transformation volume fraction. Using this modified J-M-A equation, we discussed the problems in evaluating the nucleation rate from In t vs ln (-ln (1 -x)) plot. Because a small chance in the shape of the In t vs ln (-ln (1-x)) plot makes extremely large variation in nucleation rate, J-M-A exponent n may lose it`s well-known meaning. One can not infer the whole nucleation procedure during phase transformation by any method using only the J-M-A equation. |