材料科学
晶体孪晶
打滑(空气动力学)
位错
合金
层错能
粒度
复合材料
纳米
再结晶(地质)
透射电子显微镜
结晶学
严重塑性变形
可塑性
冶金
微观结构
纳米技术
热力学
化学
古生物学
物理
生物
作者
Hailin Sun,Yunzhu Shi,Mingxing Zhang,K. Lu
标识
DOI:10.1016/j.actamat.2006.09.018
摘要
By means of surface mechanical attrition treatment, nanometer-sized grains (with an average size of 30 ± 5 nm) were generated in the surface layer of a single-phase AZ91D alloy. Transmission electron microscopy investigations showed that the strain-induced grain refinement process in AZ91D alloy includes three steps. At the initial stage twinning dominates the plastic deformation and divides the coarse grains into finer twin platelets. With increasing strain, double twins and stacking faults form and a number of dislocation slip systems are activated, including basal plane systems, prismatic plane systems and pyramidal plane systems. As a result of the dislocation slip along these systems and of the cross slips, high-density dislocation arrays are formed which further subdivide the twin platelets into subgrains. Obvious evidence of dynamic recrystallization were identified within the high-strain-energy subgrains with a further increase of strain, leading to the formation of nano-sized grains in the surface layer.
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