Medium heavy alloy fabrication with ultrafine grain and high performance via spark plasma sintering

Abstract

• Medium heavy alloys were successfully fabricated for the first time using the spark plasma sintering technique. • Nearest theoretical density achieved for the Ni-37W-5Co alloy. • Σ3 boundaries are formed in the Ni matrix. • The Ni-37W-5Co alloy has the highest UTS of 740 MPa. W-Ni-Co, W-Ni-Co-Ta, and W-Ni-Co-B 4 C medium-heavy alloys and alloy composites are developed using the spark plasma sintering technique in the current study. This work aims to investigate the structure–property correlations of the three different compositions mentioned above. The compacts are subjected to extensive metallurgical and mechanical testing. Annealing twins are formed in the Ni matrix phase, and the density of the twins revealed a difference in material strength. The densification response and tensile tests showed that the base alloy W-Ni-Co has the highest tensile strength (740 MPa), an elongation of 4.5%, and a relative sintered density of 96%.