The preferential growth behaviors of the intermetallics at the W/Co interface during spark plasma sintering

The strong electric current in spark plasma sintering (SPS) often gives sintered materials unique microstructures. In the present study, it is found that the Co3W grains formed at the W/Co bonding interface preferentially grow along [2 1 <overbar></mml:mover> <mml:mover accent="true"> 1 <mml:mo><overbar></mml:mover>0] (or its equivalent orientations) in the current direction during SPS, which is significantly different from that without current. We propose that the resistance anisotropy of grains under electromigration leads to anisotropic atomic diffusion, inducing the preferential growth of grains under current. This work may provide an approach and a theoretical foundation for the preparation of materials exhibiting directional growth.