W-Ni-Fe系焼結合金の機械的性質に及ぼす熱処理効果

概要

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The effect of heat-treatment in vacuo and hydrogen on ductility and UTS of the sintered 95.5 W-3.0 Ni-1.5 Fe and 91.3 W-5.8 Ni-2.9 Fe (by wt%) heavy alloys has been studied. The influence of composition and microstructure upon the mechanical properties of the cold worked (swaging) alloys is also presented in this paper.<BR>These materials were heated at 400-1200°C in hydrogen atmosphere and in vacuo, and the mechanical properties of heat treated alloys were tested.<BR>The effect of vacuum treatment was attributed to the removal of hydrogen embrittlement, and values of UTS and elongation increased after the vacuum treatment.<BR>The scanning electron micrographs of the fracture surfaces showed that hydrogen weakens mainly the interface between tungsten-matrix phase boundaries, and W-grain boundaries.<BR>High ductility was found to be connected to a high binding strength between the tungsten grains and the matrix phase.