The Effects of Microstructural Parameters on Distortion of Liquid-Phase-Sintered Tungsten Heavy Alloys

Abstract

The sintering of engineered components produced from powders can be enhanced by the formation of a liquid phase, but excess liquid leads to distortion and an inability to make net-shape parts. The amount of distortion depends not only on the liquid volume fraction but also on other microstructural parameters, such as grain size, dihedral angle, contiguity, and connectivity. The effects of these parameters on distortion of liquid-phase-sintered tungsten heavy alloys can be evaluated by adjusting alloy compositions and processing conditions. Sintering in microgravity extends the range of compositions that can be evaluated by eliminating settling of grains resulting from the density difference between the solid and liquid phases. In this work, data from recent microgravity experiments on the International Space Station are used for testing model predictions for the effects of microstructural parameters on dimensional stability.