Microstructure and mechanical properties of spark plasma-sintered La_(2)O_(3) dispersion-strengthened W-Ni-Fe alloy

摘要

An investigation of lanthanum oxide(La_(2)O_(3))addition to tungsten heavy alloy(WHA)with a ternary composition of W-7 Ni-3 Fe was reported in this study.The mixed powders were sintered using spark plasma sintering(SPS)technique.La_(2)O_(3)was added in increments of 0.25 wt%,0.50 wt%,0.75 wt%and 1.00 wt%to WHA,respectively.The sintered samples were characterized for microstructural evolution and mechanical properties.The influences of La_(2)O_(3)addition on density,grain size,hardness,ultimate tensile strength(UTS)and ductility on W-7 Ni-3 Fe system were discussed in this study.The highest relative sintered density of 87.95%was obtained for 0.25 wt%La_(2)O_(3)addition to W-7 Ni-3 Fe.The lowest grain size of 7.89μm was observed for 1.00 wt%La_(2)O_(3)addition.Similarly,the highest hardness and UTS of HV 533 and1110 MPa,respectively,were also obtained for the same composition.Scanning electron microscopy(SEM)and energy-dispersive spectroscopy(EDS)of the samples revealed homogenous distribution of La_(2)O_(3)in the alloy matrix.Fractography of the sintered alloy samples revealed W-W intergranular fracture.