Interfacial embrittlement in liquid-phase sintered tungsten heavy alloys

The variations in toughness of the liquid-phase sintered heavy alloys W-Ni-Fe and W-Ni-Cu have been examined. Toughness was found to be controlled primarily by the strength of the tungsten particle-matrix interfaces, which is sensitive to the rate of cooling from the sintering temperature. Furnace-cooling led to the embrittlement of these interfaces; in the case of W-Ni-Fe transmission electron microscopy identified interfacial precipitation of a W(NiFe) intermetallic compound, and in W-Ni-Cu Auger electron spectroscopy indicated interfacial segregation of the trace elements phosphorus and sulfur. This embrittlement was effectively reduced by solution treating beneath the sintering temperature and quenching