α-Fe中剪切耦合晶界迁移与裂纹相互作用的原子模拟  

Atomic Simulation of Interaction of Shear-Coupled Grain Boundary Motion with Crack in α-Iron

作　　者：闫笑寒 尹建 王忆 侯怀宇 YAN Xiaohan;YIN Jian;WANG Yi;HOU Huaiyu(School of Materials Science & Engineering,Nanjing University of Science & Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学材料科学与工程学院

出　　处：《河南科技大学学报（自然科学版）》2019年第5期7-12,M0002,共7页Journal of Henan University of Science And Technology:Natural Science

基　　金：国家重点研发计划基金项目(2017YFB0702201);先进材料教育部重点实验室基金项目(2017AML06)

摘　　要：采用分子动力学模拟方法,研究了α-Fe中Σ9[110](221)对称倾转晶界模型的剪切耦合迁移运动与晶内微裂纹的相互作用,讨论了在恒定剪切速率10 m·s^-1条件下,温度和合金原子Cr对两者相互作用的影响。模拟结果表明:在低温条件下,裂纹会在晶界耦合运动的作用下完全愈合,晶界则在裂纹的钉扎作用下发生弯曲。裂纹在晶界上的不对称固定在裂纹愈合的过程中起到重要作用,晶界的形态和结构均在吸收裂纹的过程发生变化,厚度也显著增大。裂纹的愈合过程伴随有位错的发射和运动,通过位错从裂纹尖端发射并运动至自由表面,可使裂纹不断变小乃至完全愈合。在发生剪切耦合晶界迁移的条件下,升温和添加Cr原子对裂纹愈合的影响有相似之处,两者都具有使裂纹愈合速率加快的作用。The interaction of shear coupled migration(SCM)with crack of tilt grain boundary(GB)Σ9[110](221)inα-iron was studied by using molecular dynamics simulation method.The effect of temperature and the Cr addition on the interaction under a constant shear velocity of 10 m·s^-1 was discussed.Simulation results show that crack in the FeΣ9(221)GB is completely healed under the interaction with GB at 10 K.The GB curves as a result of the pinning effect of the crack.The asymmetric fixation of cracks on grain boundaries plays an important role in the process of crack healing.In the process of crack absorption,the morphology and structure of GBs change and its thickness increases significantly.The dislocation emission and movement from the tip of crack to the free surface are the preconditions of microcrack healing.The velocity of crack healing can be increased both by rising the simulation temperature and increasing the content of Cr.

关 键 词：α铁 铁铬合金 剪切耦合晶界迁移 裂纹愈合 

分 类 号：TG14[一般工业技术—材料科学与工程]