论文部分内容阅读
采用晶体相场模型模拟获得了平均晶粒尺寸从11.61—31.32nm的纳米晶组织,研究了单向拉伸过程纳米晶组织的强化规律的微观变形机理.模拟结果表明:晶粒转动、晶界迁移等晶间变形行为是纳米晶材料的主要微观变形方式,纳米晶尺寸减小,有利于晶粒转动,使屈服强度降低,显示出反霍尔-佩奇效应.当纳米晶较小时,变形量超过屈服点达到4%,位错运动开启,其对变形的直接贡献有限,主要通过改变晶界结构而影响变形行为,位错运动破坏三叉晶界,引发晶界弯曲,促进晶界迁移.随纳米晶增大,晶粒转动困难,出现晶界锯齿化并发射位错的现象.
The crystal phase field model was used to simulate the nanocrystalline structure with the average grain size ranging from 11.61-31.32nm. The microscopic deformation mechanism of nanocrystalline microstructure under uniaxial tension was studied. The simulation results show that the grain growth, Migration and other intergranular deformation behavior is the main micro-deformation of nanocrystalline materials, nanocrystalline size decreases, is conducive to the grain rotation, the yield strength decreased, showing the inverse Hall-Peyt effect.When the nanocrystalline smaller, the deformation The amount exceeds 4% of the yield point and the dislocation motion is on. Its direct contribution to the deformation is limited. The deformation behavior is mainly affected by changing the grain boundary structure. The dislocation movement destroys the trigeminal grain boundary, causing grain boundary bending and promoting grain boundary migration. With the increase of nanocrystals, the grains are difficult to rotate, and the phenomenon of grain boundaries jagged and dislocated occurs.