Ultrafine‐grained β‐Sialon fabricated by two‐stage sintering and study on diffusion toughening of Ti–22Al–25Nb

Abstract

The ultrafine-grained β-Sialon ceramics were fabricated by spark plasma sintering at different temperatures with inorganic Al2O3–Y2O3 and Ti–22Al–25Nb intermetallic powder as composite additives. The research showed that β-Sialon ceramics achieve two-stage sintering densification. Al2O3–Y2O3 inorganic additives promoted the synthesis and densification of β-Sialon ceramics at 1125–1215°C. Ti–22Al–25Nb intermetallic powder diffused Ti and Nb elements at 1240–1425°C, thereby improving the fracture toughness of β-Sialon ceramics. The maximum fracture toughness (∼9.69 MPa m1/2) under 19.6 N was obtained for β-Sialon ceramics sintered at 1600°C.