Recycled magnesia particles in steel-based composites: Impact on thermo-mechanical behaviour

This study investigates the thermo-mechanical behaviour of steel-ceramic composites based on a matrix of austenitic stainless steel and coarse-grained magnesia particles. Composites reinforced with fresh-fused magnesia particles were compared to those reinforced with recycled magnesia sourced from spent MgO-C refractory lining bricks. The volume fraction of recycled magnesia varied from 20 vol.% to 40 vol.%. Quasi-static compression tests were performed at room temperature and within a temperature range of 800 °C – 1100 °C. Results showed that incorporating coarse-grained ceramic reinforcements into the steel matrix increased the compressive strength at all temperatures. The composite reinforced with recycled magnesia demonstrated superior mechanical properties over the variant with fresh-fused magnesia due to a smaller and more uniform particle size distribution resulting from crushing steps in the recycling process. Although non-metallic inclusions from contaminated zones of the refractory bricks were present in the recycled powder, they did not affect the overall damage mechanisms.