The Healing History Of A Void In Heterogeneous Grain Considering Small-scale Effect Under Multi-field Loads

Heterogeneous material with its unique material character distribution, has been widely used in a variety of extreme environments and multi-field. On the basis of the nonlocal elastic theory, this paper explored small scale effect on the microscopic damage healing performance within heterogeneous materials under the multi-load of force, electric, temperature and magnetic. After established a simplified three-dimensional mechanical model to meet the material parameter radial distribution and the dynamic construction of a heterogeneous grain, the author figured out the strain energy in the edge of void diffusion layer inside heterogeneous grain according to nonlocal elastic theory. Then combined lattice diffusion and chemical potential gradient, the analytical expressions of void shrinkage rate and healing time were obtained. The results show that the small-scale effect could promote the self-healing of a void within heterogeneous grain through increasing the shrinkage rate and reducing the stable size of holes; when the exponent of material properties radial distribution is 1, the process of shrinkage would get the best; changing the ambient temperature appropriately and applying the specific electromagnetic field can also accelerate the healing process; the electronic potential would somehow hinder the void healing in piezoelectric crystal.