Significantly elevated strength of W-Ni3Al alloy by adding trace boron element

W-Ni ₃ Al alloys have potential application in kinetic energy penetrator, but there are some problems such as high sintering temperature, large tungsten grain size, and poor mechanical properties. In this study, fine-grained W-Ni ₃ Al-B alloys with excellent mechanical properties were successfully fabricated at a low temperature of 1150 °C by adding trace boron powder (B) and using spark plasma sintering (SPS). For the addition of B in the W-Ni ₃Al alloys, the low melting point B ₂O ₃ phase was formed and its thermite reaction released extra heat, promoting the sintering of the alloys. However, with the increasing of B content (0.1–0.7 wt%), the more hard brittle phases were formed, damaging the strength of sintered alloys; at the same time, the more B ₂O ₃ phase was evaporated due to the more released heat, causing occurrence of pores. Among all B-containing W-Ni ₃ Al alloys, the 0.1B alloy exhibited the optimal mechanical properties with the bending strength of 1375.88 ± 19.20 MPa (higher 99.32% than that of the 0B alloy) and a high hardness value of 71.6 ± 0.29 HRA. By analyzing 0.1B alloy`s microstructure, its good mechanical properties were related to the small tungsten grain size, heterostructural binder phase, minimal formation of hard brittle phases, dislocation movements being obstructed by the Al ₂O ₃ phase, and the tungsten transgranular cleavage fracture mode.