Microstructures and phase formation in rapidly solidified Sm–Fe and Sm–Fe–Ti–C alloys

Partially ordered Sm 2 Fe 17 , closer to the SmFe 7 structure, formed upon melt spinning of Sm 11 Fe 89 . A strong dependence of grain size on the wheel speed was also observed, with wheel speeds less than 40 m/s generating grain sizes above the single domain limit for Sm 2 Fe 17 N x . The addition of Ti and C resulted in an order of magnitude grain refinement compared to the binary alloys. The Ti and C also effectively inhibited grain growth during annealing. The nitrided Sm–Fe–Ti–C alloys also displayed a rapid decrease in coercivity with decreasing grain size, which was attributed to increased exchange interactions.