Strength of Hot-pressed α-sialon

Abstract

Five kinds of α-sialon were fabricated by hot-pressing. The composition of them is M_x(Si_9.3Al_2.7)(O_0.9N_15.1). Metal compound M which dissolves interstitially is Ca, Mg, Y, Nd or Er, and x is 0.9 in case of Ca and Mg, 0.6 in Y, Nd and Er. The bending strength and the fracture toughness of α-sialon were measured. The strength was 420-605MPa at room temperature, and degraded at 1200°C to 60-70% of that at room temperature. The fracture toughness was 3.58-3.90MN/m^3/2. A cluster of large grains was identified as a fracture origin.