平板撞击试样热愈合处理内裂纹形态研究

Morphology Change during Crack Healing of Impacted Sample

平板撞击试样内裂面呈锯齿状。在本文中,愈合处理采用了整体愈合、剖分愈合及高温显微镜下原位加热愈合等方法。在实验中,观察到锯齿状内裂面的逐渐消失、退化现象及高温显微镜下裂纹边界棱角的钝化现象。作者认为,锯齿状内裂面的退化和边界棱角的钝化是高曲率、高表面能引起该处原子向周围扩散的结果;高温显微镜的原位加热愈合方法无法对特殊三维形态的内裂纹愈合过程进行真实、全面的观察。此外,还从热动力学角度,对平板撞击试样内裂纹愈合形态的演化进行了分析。

By observation, there are zigzag on the surface of inner crack impacted samples. Healing process used many methods such as integer, division, microscope with heating stage. During healing, the zigzag disappeared and crack boundary passivated. The big curvature result in atom diffusion and microscope with heating stage don′t fit observation of inner crack healing in situ. The morphology change during crack healing was analyzed based on diffusionkinetics and thermodynamics.