Application of the Peierls–Nabarro Model to Symmetric Tilt Low-Angle Grain Boundary with Full Dislocation in Pure Magnesium  

作　　者：Tou-Wen Fan Xiu-Bo Yang Jiang-Hua Chen Ling-Hong Liu Ding-Wan Yuan Yong Zhang Cui-Lan Wu 

机构地区：[1]Center for High-Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University [2]Department of Applied Physics, School of Physics and Electronics, Hunan University [3]Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University [4]College of Science, Central South University of Forestry and Technology

出　　处：《Acta Metallurgica Sinica(English Letters)》2016年第11期1053-1063,共11页金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos. 11427806, 51471067, 51371081, 51171063, 51501059 and 51501060);the National Basic Research (973) Program of China (No. 2009CB623704);the Chinese Postdoctoral Science Foundation (No. 2015M582324);the Hunan Provincial Natural Science Foundation (No. 14JJ4052);the Science and Technology Project for Good Postdoctoral Education of China (No. 2015RS4020)

摘　　要：Three types of symmetric （1120） tilt low-angle grain boundaries （LAGBs） with array of basal, prismatic, and pyramidal edge full 〈a〉 dislocations in pure Mg have been studied by using the improved Peierls-Nabarro model in combination with the generalized stacking fault energy curve. The results show that with decreasing distance between the dislocations in all the three types of tilt LAGBs, the stress and strain fields are gradually suppressed. The reduction extent of the stress and strain fields decreases from the prismatic to basal to pyramidal dislocations. The variation of dislocation line energy （DLE） for all tilt LAGBs is divided into three stages： DLE changes slightly and linearly when the distance is larger than 300 A, - 10%; DLE declines exponentially and quickly when the distance goes from 300 to 100 A, ,- 70%; and finally, the descent speed lowers when the distance is smaller than 100 A and the dislocation core energy is nearly half of the DLE. The grain boundary energy （GBE） decreases when the tilt angle of LAGB increases from1 ° to 2° for all cases. The tilt LAGB consists of pyramidal dislocations always has the largest GBE, while that with array of prismatic dislo- cations has the smallest one in the whole range. The Peierls stress of dislocation in tilt LAGB is nearly unchanged, the same as that of single dislocation. This work is useful for further study of dissociated dislocation, solute segregation, precipitate nucleation in tilt LAGB and its interaction with single dislocations.Three types of symmetric （1120） tilt low-angle grain boundaries （LAGBs） with array of basal, prismatic, and pyramidal edge full 〈a〉 dislocations in pure Mg have been studied by using the improved Peierls-Nabarro model in combination with the generalized stacking fault energy curve. The results show that with decreasing distance between the dislocations in all the three types of tilt LAGBs, the stress and strain fields are gradually suppressed. The reduction extent of the stress and strain fields decreases from the prismatic to basal to pyramidal dislocations. The variation of dislocation line energy （DLE） for all tilt LAGBs is divided into three stages： DLE changes slightly and linearly when the distance is larger than 300 A, - 10%; DLE declines exponentially and quickly when the distance goes from 300 to 100 A, ,- 70%; and finally, the descent speed lowers when the distance is smaller than 100 A and the dislocation core energy is nearly half of the DLE. The grain boundary energy （GBE） decreases when the tilt angle of LAGB increases from1 ° to 2° for all cases. The tilt LAGB consists of pyramidal dislocations always has the largest GBE, while that with array of prismatic dislo- cations has the smallest one in the whole range. The Peierls stress of dislocation in tilt LAGB is nearly unchanged, the same as that of single dislocation. This work is useful for further study of dissociated dislocation, solute segregation, precipitate nucleation in tilt LAGB and its interaction with single dislocations.

关 键 词：Tilt grain boundary Generalized stacking fault energy Magnesium alloy DISLOCATION Peierlsstress 

分 类 号：TG146.22[一般工业技术—材料科学与工程]