黄铜薄膜试样在透射电镜中原位拉伸观察表明，在平衡条件下加载裂尘发出的位错钝化成无位错区，它是一个应变很高的异常弹性区。当缺口足够尖锐，外加载荷足够大时，这个非线弹性区中的应力有可能达到原子键合力，从而使纳米级微裂纹在无位错区中不连续形核，或从钝化的原裂纹顶端形核。这个微裂纹一旦形核，即使保持恒位移，也将钝化成空洞或缺口。
The in situ tensile test under TEM for thin foil specimen of brass showed that a lot of dislocations could be emitted from a loaded crack tip and a dislocation free zone(DFZ) could form after reaching equilibrium. The DFZ was a nonlinearly elastic zone with large strain(ε≈0. 1) and the stress in the DFZ might equal to the cohesive strength σ_(th) when the crack tip was sharp enough and an applied stress was large enough. As a result, a nanocrack initiated discontinuously in the DFZ or sometimes at a blunted-crack tip. As soon as the nanocrack nucleated, it would quickly blunt into a void even under keeping constant displacement.
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