Roughening of the interface between grains and liquid matrix in sintered TaC-20Ni

Abstract

The grains in TaC-20 wt pct Ni alloy prepared by liquidphase sintering at 1480°C have orthorhombic shapes with flat {100} faces and sharp edges. These grains show abnormal growth. When sintered at 2020°C, the grains develop round edges and corners, and the grain growth is nearly normal. Such a grain shape change indicates that the interface between the grains and the liquid matrix undergoes roughening transition with temperature increase. The interface roughening transition is reversed when a specimen initially sintered at 2020°C is heat treated again at 1400°C.