Functional Designing and Development of Evaluation of Residual Stress in the Surface of Inorganic Materials

1不同材料残余应力的评价在19.6N的初始载荷下，单晶碳化硅的残余应力观察距离大于玻璃(Na-Ca-Si-O)。碳化硅和玻璃的距离分别为200μm和300μm。在相同距离下，碳化硅中的残余应力比玻璃中的残余应力大好几倍。2.热处理后残余应力的变化在Si-Al-Li-O系玻璃中，热处理使残余应力降低，在530℃的应变点附近，残余应力趋于零。析晶玻璃的残余应力曲线向高温侧移动了约100℃。在单晶碳化硅中，残余应力在800℃左右开始下降，在1400℃，2小时的热处理时，残余应力为零。多晶碳化硅的残余应力曲线略有向低温侧移动。3材料分析和讨论所有材料都观察到热处理后残余应力的降低，并伴随着三维的压痕形状。对离子扩散的分子动力学模拟表明，一些离子如Ti~(2+)和Lt；4~+和Gt~(2+)具有间歇性运动。单晶碳化硅的电子显微镜观察表明，沿(0001)晶面的基面滑移引起了层错，且基面滑移在接近压痕的位置和高温处理的样品中较为突出。对半导体材料、光学材料和结构材料具有重要意义的耐热性能的大小顺序为：碳化硅和晶化玻璃。残馀应力评估技术可以检测应变变化，有助于设计高耐热、高性能的材料。

1 Evaluation of residual stress of various materialsThe range of distance in which the residual stress was observed was larger for single crystal SiC than for glass (Na-Ca-Si-O) at the primary load of 19.6N. The distance was 200μm for SiC and 300μm for glass, respectively. It was also found that the residual stress in SiC was several times larger than that in glass at an equivalent distance. The load at equivalent distance was 165MPa in SiC and 40MPa in glass, respectively.2 The change of residual stress after heat treatmentIn Si-Al-Li-O system glass, the residual stress was reduced by heat treatment and became zero near the strain point of 530℃. The residual stress curve of the crystallized glass shifted to high temperature side by about 100℃. In single crystal SiC, the residual stress started to decrease at about 800℃ and became zero at the heat treatment of 1400℃, 2hrs. The residual stress curve of polycrystalline SiC shifted a little to low temperature side.3 Analysis of materials and discussionThe reduction of residual stress by heat treatment was observed in all materials and was accompanied with three dimensional shape of the indentation. MD simulation of the diffusion of ions showed that some ions such as Ti^<4+> had intermittent movement. It is considered that the increase in heat resistance by crystallization was caused due to the suppression of viscous flow of glass owing to the crystal phase.TEM observation of single crystal SiC showed that basal slips along (0001) caused stacking faults and that the basal slip was prominent at the points close to the indentations and in the specimen which was heat treated at higher temperature. The heat resistance property which is important for semiconductor, optical and structural materials were in the order of SiC > crystallized glass > glass. The technique to evaluate residual stress can detect strain change and contribute to designing materials with high heat resistance and high functions.