纳米孔洞发射位错的愈合机理研究

Study of Healing Mechanism of Nano-hole with Emission Dislocations

孔洞影响材料的使用寿命,因此孔洞愈合的机理研究有重要意义。本研究采用晶体相场(Phase Field Crystal,PFC)模型,研究纳米孔洞缺陷在单轴压应变作用下的微观愈合过程中位错发射的特征。结果表明,在压应变作用下,体系能量累积到某一临界值时,孔洞发生变形并长出凸口,在凸口处位错开始萌生。随着压应变的增加,凸口处位错开始发射,使得孔洞不断缩小,最终通过该方式实现孔洞愈合。上述结果表明,位错发射机制是纳米孔洞愈合的主要形式,对防止材料裂纹的扩展以及提高材料的寿命具有重要的理论意义。

Holes affect the service life of materials,so it is of great significance to study the mechanism of hole healing.In this study,Phase Field Crystal(PFC)model was used to study the characteristics of dislocation e-mission during the micro-healing process of nano-hole defects under uniaxial compressive strain.The results show that under the compressive strain,when the system energy accumulates to a certain critical value,the holes deform and grow out of the convex,and the dislocations begin to initiate at the convex.With the in-crease of compressive strain,dislocations begin to emit at the convex,which makes the hole shrink continu-ously,and finally the hole healing is realized in this way.The above results show that the dislocation emission mechanism is the main form of nano-hole healing,which is of great theoretical significance to prevent the propagation of cracks and improve the life of materials.