高温应变作用下小角度晶界湮没过程的晶体相场模拟

【目的】采用晶体相场模型模拟应变作用下晶界的变形过程。【方法】分别模拟了对称倾侧双晶体系在远离熔点温度和接近熔点温度时,在外加应力作用下小角度晶界的湮没过程。【结果】研究表明,小角度晶界同一侧晶界处相邻位错组的柏氏矢量夹角为60°,并且当体系接近熔点温度时,晶界处位错组周围出现预熔区域。【结论】晶界处的位错组在应力作用下进行滑移运动,两种情况中晶界位错的湮没规律基本相同,但由于预熔情况的出现,使得位错运动的阻力降低,位错运动的速度较快,湮没时体系能量减小得更多。

Phase Field Crystal Simulation of Annihilation Process of Small-grain Boundary under Stress at High Temperature

Objective]Grain boundary（GB）deformation process under stress was modeled with the phase-field crystal approach.Methods]We simulate the structure of symmetric tilt GB and its annihilation process under stress when the system temperature far from the melting point and close to the melting point,respectively.Results]The Burgers vector of the two adjoining double-array dislocations along the small-angle GB has an angle about 60＆#176;,and a local premelt-ing occurs around the dislocations as the premelting point is approached from below.Conclu-sion]Dislocations of the GB begin to glide under stress,and the process of annihilation is similar in the two kinds of conditions.As premelting occurs,it diminishes the resistance and leads to a faster movement of the dislocations,and it also causes more energy reduction of the system during the process of annihilation.