单晶硅裂纹尖端的位错发射行为

Dislocation emitting behavior from crack tips in single silicon

利用透射电镜原位观察了单晶硅压痕裂纹尖端位错及位错偶沿滑移面的发射行为。考察了滑移面取向、外荷对发射位错及塑性区的影响。结果表明 :在I型载荷作用下 ,滑移面与裂纹面夹角要影响从裂纹尖端发射的位错数量及塑性区。发射出的位错可沿最大切应力方向改变运动方向或交换滑移面运动。实验观察的位错宽度平均值为 2 2 .0nm ,与Peierls位错框架模型计算的 2 3.

Dislocation emissions on the slip plane from crack tips in silicon were observed through transmission electron microscopy. The effects of the slip plane orientation and load on dislocation emission or plastic zone have been investigated. The results show that the angle between slip plane and crack plane has an effect on dislocation structure and plastic zone under the I mode load, and the direction of the movement of dislocation emission may change along the direction of the maximum shear stress, or move in zigzag on different slip planes alternatively. The experimental average 22.0?nm of dislocation width approximates to 23.6?nm calculated by Peierls dislocation model.