(color online) The crystallization mechanism of as-quenched ribbons with different initial phase structure. , , and Δ H₃ are the enthalpy change of the reactions: (1) amorphous Nd₂Fe₁₇B_x, (2) Nd₂Fe₁₇B_x Nd₂Fe₁₄B, and (3) amorphous Nd₂Fe₁₄B, respectively.^[43]