Study on combination of in-situ dispersion and secondary ball milling for W-Ni-Co tungsten heavy alloy

In this study, a combination of the in-situ dispersion and the secondary ball milling method was used to synthesize the W-Ni-Co model alloys with doping different amounts of yttrium. The results demonstrate that the presence of yttrium can promote the formation of the in-situ oxide dispersoids during mechanical alloying and, thereby, significantly influences sintering behavior and characteristics of the model alloys. In addition, the concentration of yttrium in the alloy can alter the size and distribution of the γ(Ni,Co) binder phase, corresponding difference in mechanical properties of the material. The large Y-W-O oxide was found in the alloy with a relatively high content of yttrium. It has been identified as the Y2WO6 phase, which could be considered as the interaction between the Y-rich oxide and tungsten during mechanical alloying. The crystal structure of the oxide phase could be further changed or transformed by subsequent sintering.