Stress perturbations and material defects can significantly affect the fracture initiation and propagation behaviors in brittle materials. In this work, we show that (110)[110] cleavage in silicon deflects onto (111) plane in the presence of contact stresses. The deflection is however not permanent as the crack returns to the (110) plane after a certain length of propagation, even in the case where the crack velocity is up to 78% of the Rayleigh wave speed. The recovery behavior indicates that the (110)[110] cleavage is invariably prevailing when perpendicular to the maximum stress. Following this indication, it can be concluded that the observed (110)[110]–(111) deflection in previous literature is more likely driven by the external disturbance rather than the crack velocity induced toughness evolution. We also highlight that the extra energy for the (110) recovery is minimized at the expense of a large propagation distance upon the plane switch.

应力扰动和材料缺陷会显着影响脆性材料中的断裂萌生和扩展行为。在这项工作中，我们表明在存在接触应力的情况下，硅中的（110）[110]裂解会偏转到（111）平面上。然而，挠曲不是永久的，因为即使在裂纹速度达到瑞利波速的78％的情况下，裂纹在一定的传播长度后会返回（110）平面。恢复行为表明，当垂直于最大应力时，（110）[110]劈裂总是占优势。根据这种指示，可以得出结论，先前文献中观察到的（110）[110]-（111）挠度更可能是由外部干扰驱动的，而不是由裂纹速度引起的韧性演化引起的。