Effects of Sintering Temperature on Properties of W-9.8Ni-4.2Fe Alloys Fabricated by Spark Plasma Sintering

The effects of sintering temperature on the properties of W-9.8Ni-4.2Fe alloys fabricated by spark plasma sintering were studied. The peak, base, repetition frequency of pulse electric current and the initial average no-load current were chosen as 3000A, 360A, 50Hz and 1200A during the sintering process, respectively. Research results show that W-9.8Ni-4.2Fe alloy, consolidated by SPSing for 6min at 1250 degrees C under a pressure of 30MPa, has a relative density of 97.72%, hardness of 41.8HRC, transverse rupture strength of 1443MPa, and compression strength of 2640MPa. Its combination properties are topmost among all specimens sintered at various temperatures, which is attributable to the microstructural characteristics of dense microstructure, uniform distribution of binder, low connectivity of W-W and good metallurgic bonding. The optimal fracture surface in relation to the microstructure is dominating tungsten intergranular fracture, accompanied by local transgranular fracture in tungsten phase and ductile avulsion of the binder phase.