Gravitational effects during liquid phase sintering

Liquid phase sintering (LPS) is routinely used to consolidate dense components. However, there are several problems during LPS that have their origin in gravitational effects. Under terrestrial conditions, to ensure structural stability and net-shaping, this technique is generally limited to high solid contents. In addition, there are several unresolved issues pertaining to the microstructural evolution and compact reshaping during sintering. Experimental conditions present during microgravity processing have allowed liquid phase sintering over a wide range of solid–liquid ratios than possible on earth. A rare opportunity was provided to conduct extensive liquid phase sintering experiments on tungsten heavy alloys aboard the space shuttle Columbia as a part of the International Microgravity Lab (IML-2) and Microgravity Space Lab (MSL-1 and MSL-1R). Results from these experiments show novel behavior associated with microgravity both in microstructural as well as macrostructural evolution.