Impression and Compression Creep of SiAlON Ceramics

Abstract

Concurrent impression and uniaxial compression creep studies were performed on three Yb‐SiAlON materials. Stress exponents were approximately 1 in compression and 2 in impression. The higher stress exponents were due to the complex stress field in the impression creep test, which caused microstructural dilation. The dilated multi‐grain junctions also became filled with additional intergranular glassy phase. Focused ion beam milling and in situ lift‐out specimen preparation combined with transmission electron microscopy was successful in identifying microstructural changes after creep testing. These observations have important implications in the design of creep‐resistant materials in complex stress fields.