MoSi2基复合材料的高温裂纹自愈合行为Crack healing of a MoSi2-based composite at high temperatures
冯培忠,王晓虹,贾志永,曲选辉
摘要(Abstract)：
采用X射线衍射、扫描电镜和三点弯曲强度测试方法研究MoSi2基复合材料Vickers压痕裂纹试样的高温裂纹自愈合行为和强度的变化。结果表明:Vickers压痕在材料表面造成明显裂纹并引起强度的急剧衰减。经过1500℃保温1h处理,在材料表面形成一层SiO2玻璃膜,材料表面的裂纹表现出良好的自愈合性能,抗弯强度恢复到345.3MPa。裂纹自愈合机理主要是高温下原子扩散作用引起的裂纹钝化和裂纹面的连接,另外材料表面SiO2玻璃层的形成也将促进表面缺陷和微裂纹的愈合。裂纹愈合是强度恢复的主要原因,而热处理对裂纹附近应力的松弛作用和表层压应力的形成也都有利于材料强度的提高。
关键词(KeyWords)： 二硅化钼;高温裂纹自愈合;弯曲强度
基金项目(Foundation): 高等学校博士学科点专项科研基金(20070290523)
作者(Author): 冯培忠,王晓虹,贾志永,曲选辉
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