摘要
研究不同密度的 Al2 O3 / Si C纳米复合材料在退火条件下的裂纹愈合行为。利用维氏压痕法引入可控的预制裂纹 ,通过测量退火前后材料抗弯强度的变化来表征裂纹愈合程度。当退火温度在 85 0℃以上时 ,裂纹愈合效应随退火温度提高明显增强 ,在 115 0℃左右退火 1h后 ,不同密度的试样的抗弯强度均恢复到试样的固有强度。裂纹愈合的机制主要归结于退火过程中残余应力的驰豫导致扩散键合和裂纹表面碳化硅颗粒的氧化作用。然而 。
Al 2O 3/ SiC nanocomposites with different relative density was used to investigate the crack healing behavior in annealing. Vicker's indentation method was used to induce the controlled cracks. The changing of four points bending strength of the sample with indentation was used to evaluate the healing effects indirectly. It is found that the healing effect increase strongly along with the increasing of annealing temperature above 850℃. After annealed at about 1150℃ for one hour, the bending strength of all the different relative density sample with indentation crack almost recover to the original strength without crack. The crack healing mechanism is attributed to the relaxation of residual stress and the oxidation of SiC particle at the crack surface. However, the excess oxidation will reduce the healing effect.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2002年第10期3-6,共4页
Journal of Materials Engineering
基金
国家自然科学基金资助项目 ( 5 9432 0 6 )
清华大学 985资助项目 ( ZA0 2 )
