Al-12.7Si合金表面强烈塑性变形诱发的纳米化  

NANOCRYSTALLIZATION OF Al-12.7Si ALLOY INDUCED BY SURFACE INTENSE PLASTIC DEFORMATION

作　　者：刘刚[1] 严文聪[1] 于福晓[2] 赵刚[3] 赵骧[2] 左良[1] 

机构地区：[1]东北大学研究院,沈阳110004 [2]东北大学材料电磁过程研究教育部重点实验室,沈阳110819 [3]东北大学材料各向异性与织构教育部重点实验室,沈阳110819

出　　处：《金属学报》2011年第6期649-654,共6页Acta Metallurgica Sinica

基　　金：国家高技术研究发展计划项目2008AA030701;国家科技支撑计划项目2009BAE80B01资助~~

摘　　要：对Al-12.7Si合金进行表面机械研磨处理,在表层制备纳米-微米梯度结构,利用XRD和TEM研究结构演变过程.Al-12.7Si合金形变诱发的纳米化机理归纳如下:在外加载荷的反复作用下,Al基体高密度位错通过滑移、湮灭和重组形成位错胞/亚微晶;通过不断吸收位错,位错胞/亚微晶之间的取向差逐渐增大;亚微晶内高密度位错重复上述过程,使晶粒尺寸减小、取向差增大,最终形成等轴状、取向呈随机分布的纳米晶.Si颗粒通过内部位错单滑移或多滑移所产生的切割及部分溶解而细化,并随着Al基体的塑性流动而呈弥散分布.Gradient nano-micro structured surface layer was synthesized on AI-12.TSi alloy by means of surface mechanical attrition treatment. The microstructural evolution was examined by XRD and TEM. he surface intense deformation induced nanocrystallization mechanism was summarized as follows： upon the application of repeated loads, dislocation cells/sub micro-grains form through slips, annihilations and recombinations of high density of dislocations in A1 coarse grains. The misorientations between the dislocation cells/sub-micro-grains increased by continuously absorbing more dislocations. High density of dislocations in sub micro-grains developing in above route led to the reduction of grain size and the increment of misorientations between the refined grains, and finally equiaxed nc grains with random orientations formed. The refinement of Si particles was found to be carried out through singleor multi-slips of internal dislocations and partial dissolution, then the refined Si particles distributed uniformly due to the plastic flows in A1 matrix.

关 键 词：表面机械研磨处理 Al-12.7Si合金 纳米化机理 

分 类 号：TG142.71[一般工业技术—材料科学与工程]