Effect of tantalum addition method on microstructure and mechanical properties of the 90(W 20Ta)–Ni–Fe alloy

The method of adding the initial elements greatly affects the structure and mechanical properties of a tungsten alloy. In this study, the 90(W 20Ta)–Ni–Fe alloy was prepared by the direct addition of elements and W Ta pre-alloying. The element diffusion and phase transformation behavior under different states are discussed. The matrix phase to segregate into lumpy Ni ₃Ta and Fe ₂ Ta phases after sintering by directly adding tantalum, which deteriorated the structure of the alloy. The pre-alloyed group first formed body-centered cubic W Ta solid solution with fine particles through mechanical milling. During the sintering process, the tantalum element gradually precipitated to form the acicular Ni ₃Ta phase, which improved the uniformity of the microstructure. Through W Ta pre-alloying, the main failure mode transformed from an interfacial fracture to a trans-granular fracture, which increased the strength of the alloy by 130%.