Dilatometric analysis on the sintering behavior of nanocrystalline W-Cu prepared by mechanical alloying

摘要

Unlike conventional W-Cu powder, the sintering of nanocrystalline W-Cu powder was significantly enhanced at solid phase sintering temperature. In the present study, in order to clarify this enhanced sintering behavior of nanocrystalline W-Cu powder prepared by mechanical alloying, the sintering behavior during heating stage was analyzed by dilatometry with various heating rates. The sintering of the nanocrystalline W-Cu powder was characterized by the densification of two stages, having two peaks in shrinkage rate curves. The temperature at which the first peak appeared was well below the Cu melting point and significantly dependent on the heating rate. On the basis of dilatometric data and microstructural observation, the possible mechanism for the enhanced sintering of the nanocrystalline W-Cu powder in the solid phase was attributable to the coupling effect of the sintering occurring inside as-milled powder and the sintering between powder particles.