Shrinkage Kinetics during Sintering W-Ni-Fe Heavy Alloy with Ultrafine Grain

Abstract

The characteristics of swell-shrinkage kinetic curve during sintering the compact of W-Ni- Fe 10% with primary mean grain size less than 200 nm in hydrogen atmosphere was researched by high tem- perature dilatometer. And the effects of the average size of tungsten particle and green density on shrinkage commence temperature, sharp shrinkage temperature and shrinkage rate were also studied. It shows that shrink age commence temperature and sharp shrinkage temperature of the compact with ultrafine grain are 970℃ and 1240 ℃ respectively. The maximum shrinkage rate is 9 μm/℃. The shrinkage ratio decreases with the increase of green density and increases with the increase of sintering temperature.