Necking mechanisms on porous metallic glass and W compacts using electro-discharge sintering

Abstract

We report on the formation mechanism of neck during electro-discharge sintering (EDS) upon various electrical input energy using Cu-based metallic glass and W powders. Microstructural investigation reveals that crystalline phases are observed preferentially on the surface of the Cu-based metallic glassy powder indicating energy concentration occurs at the powder surface. Moreover, it is clearly observed that needle-like morphology on the W powder surface suggesting that both surface melting and evaporation take place, followed by rapid freezing the substance. Therefore, these results strongly support that formation of neck during EDS is closely connected to the energy convergence on the thin layer of the powder surface inducing melting or evaporation. (c) 2011 Elsevier B.V. All rights reserved.