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Quaternary Heusler alloy Ni 50 Mn 8 Fe 17 Ga 25 ribbons have been prepared by the melt-spun method. The ribbons exhibit large negative magnetoresistance ͑MR͕͒=͓R͑H͒ − R͑0͔͒ / R͑0͖͒ over a wide temperature region, particularly in the region during the martensitic phase transformation. The MR decreases significantly after annealing. The large MR is isotropic and is mainly attributed to the local magnetic disorders, magnetic clusters, and heterogeneity. The maximum MR at martensitic transformation may be due to the redistribution of electrons and the increase of phase boundary scattering. This feature adds a useful functionality to the already interesting Heusler alloys.

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The brazing of TiC ceramic to iron was carried out at 1123-1273 K for 5-20 min using Ag-Cu-Zn filler metal. Interface structure and shear strength of joints were investigated, the former via electron probe microanalysis, scanning electron microscopy, and Xray diffraction, and the latter via the shearing method. The results show the formation of three phases in the TiC ceramic-iron joint, namely, copper base solid solution, FeNi, and silver base solid solution. The highest joint shear strength of 256 . 5 MPa is obtained for a brazing temperature of 1173 K and brazing time of 5 min.STWJ/408