Effect of local pressure on the crystallization product of amorphous alloys induced by mechanical milling

An Fe-N amorphous alloy was produced by mechanical milling a mixture of α-Fe and h-BN. Its crystallization process was investigated by mechanical milling (MM), annealing at ambient pressure and under high pressure. The crystallization product of the Fe-N amorphous alloy induced by MM is ε-Fe_xN alloy, which is different from its thermal crystallization product of γ′-Fe₄N but is the same as its high pressure crystallization product obtained at temperatures between 690 and 800 K under pressures of 3-4 GPa. The difference between the mechanical crystallization product and thermal crystallization is attributed to the effects of local pressure and temperature on the crystallization thermodynamics.