Effect of conventional and microwave sintering on the properties of yttria alumina garnet-dispersed austenitic stainless steel

The current study examines the effect of heating mode, temperature, and varying yttria alumina garnet (YAG) addition (5 and 10 wt pct) on the densification and properties of austenitic (316L) stainless steel. The straight 316L stainless steel and 316L-YAG composites were heated in a radiatively heated (conventional) and 2.45 GHz microwave sintering furnace. The compacts were consolidated through solid state as well as supersolidus sintering at 1200 °C and 1400 °C, respectively. Both 316L and 316L-YAG compacts couple with microwaves and heat to the sintering temperature rapidly (∼45 °C/min). The overall processing time was reduced by about 90 pct through microwave sintering. As compared to conventional sintering, compacts sintered in microwaves exhibit higher densification and finer microstructure but no corresponding improvement in mechanical properties and wear resistance. This has been correlated to elongated, irregular pore structure in microwave-sintered compacts.