In situ observation of the micro-hole healing process

The Research on the mechanism of the internal crack healing in metals is an important basic work for improving metal quality and prolonging its lifetime, and it is very significant for developing the theory of materials. In the paper, in situ observation of the internal crack healing process on the section of pure copper sample under high temperature microscope, the fine structure of healed micro-holes are observed under scanning electron microscope. Observation results showed that the micro-voids of tens micron begin to be healed at the temperature of 750degreesC, and obviously healed at the temperature of 900degreesC. The fine structure of the healed micro-holes consists of some agglomerate particles at the scale of micrometer and much smaller particles on these agglomerate particles. According to the above observation, phenomenological model of micro-hole healing are presented, the healing process is passivating of hole edge on the observation section, shape regularization of micro hole; inner interface motion of micro hole in the matrix.