一种β-sialon的显微结构和蠕变行为

MICROSTRUCTURE AND CREEP BEHAVIOR OF A β -SIALON

研究了一种以Sm黄长石相固溶体 (M′)为晶界相的热压 β-sialon陶瓷在 12 5 0～ 135 0℃和大气下的四点弯曲蠕变行为 .蠕变速率对应力作图获得 12 5 0 ,130 0 ,135 0℃下的应力指数分别为 1.45 ,1.5 1,1.72 ,蠕变速率和温度之间的Arrhenius图给出了蠕变激活能为 5 76kJ·mol- 1 .显微结构观察表明仅在三晶界处发现了空洞 .

The four-point bending creep behavior of a hot-pressed β-sialon with Sm-melilite solid solution (denoted as M') as intergranular phase was studied in the temperature range of 1250-1350°C in air. Creep rates plotted against stresses gave stress exponents of 1.45, 1.51 and 1.72 at 1250, 1300 and 1350°C respectively, and Arrhenius plot between the creep rates and the temperature yields a creep activation energy of 576 kJ×mol-1. Cavities are found to be mainly at the triple grain junctions. Diffusion coupled with grain boundary sliding, resulting the formation of the wedge-shaped cavities, is identified as the dominant creep mechanism.