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利用改进压轮法预制出与以往不同的（１０）面［１１］方向的平直裂纹．采用三点弯曲法测定裂纹临界应力强度因子 Ｋ＿ｃ，用扫描电镜分析裂纹面断口的形貌，研究了硅单晶中的脆韧性转变（ＢＤＴ）行为 结果表明，随着加载速率从 ４μｍ／ｓ增加到 １６μｍ／ｓ，脆韧性转变温度向高温方向移动，转变区间由３５Ｋ减至狭小的８Ｋ，在这一区间内临界应力强度因子突然上升．在脆韧性转变过程中当裂纹扩展越过塑性饱和区后出现（１）和（１）面的交滑移，说明脆韧性转变与滑移系的启动有密切的关系
Using the improved pressure wheel method to precast out of the past (1 0) plane [11 ] direction of the flat crack. The critical stress intensity factor K_c of the crack was measured by three-point bending method. The morphology of the fracture surface was analyzed by scanning electron microscopy. The brittle-ductile transition (BDT) behavior in the silicon single crystal was studied. The results show that with the increase of the loading rate from 4μm / s, To 16μm / s, the brittle-ductile transition temperature shifts to high temperature, and the transition range decreases from 35K to 8K. In this interval, the critical stress intensity factor suddenly increases. The slip of the (1) and (1) surfaces occurs after the crack propagates beyond the plastic saturation zone during the transition of brittleness and ductility, indicating that the brittle-ductile transition is closely related to the start of the slip system