Fe3B/Nd2Fe14B nanocomposite magnetic powders were prepared by melt quenching and heat-treatment.The microstructure and crystallization behavior were studied by X-ray diffraction(XRD),differential thermal analysis(DTA),and vibrating sample magnetometer(VSM).It is found that the heating-up rate will affect the formation and decomposition of the phases at a certain extent for melt-spun Fe3B/Nd2Fe14B powders.It is confirmed that the overquenched Nd4.5Fe77B18.5 and Nd4Fe77Cr0.5B18.5 samples were decomposed to Fe3B/Nd2Fe14B via metastable Nd2Fe23B3 during annealing at 973 K for 7 min.Hci,Jr and(BH)max have been obviously improved for the samples annealed above 953 K for 10 min.The addition of Cr is effective for refining the grain size and increasing the intrinsic coercivity,resulting in an improvement of hard magnetic properties.