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采用超音速微粒撞击工艺在Mg-Gd系稀土变形镁合金材料上成功制备出纳米晶结构表层,通过光学显微镜和高分辨透射电镜研究了由表层沿厚度方向不同变形层区的微观结构特点及微观组织细化特征.结果表明:整个塑性变形层的微观组织和结构呈梯度分布,在样品表层形成了尺寸为10~20 nm晶界清晰的纳米晶粒,亚表层主要为高密度的位错缠结、位错列、位错网络及被位错分割形成的细小残余孪晶或微条带状亚结构,靠近基体的变形层区以形变孪晶和块状亚结构为主.分析认为动态再结晶是细化组织和导致高能亚结构转变为纳米晶粒的最关键因素.
Nanostructured surface layers were successfully prepared on Mg-Gd rare-earth modified magnesium alloy by supersonic particle impact technique. Microstructural features and microscopic features of different deformed layers along the thickness direction were studied by optical microscope and high-resolution transmission electron microscope The results show that the microstructure and structure of the whole plastic deformation layer are gradient distribution, and the nanocrystalline grains with the size of 10 ~ 20 nm are formed on the surface of the sample. The sub-surface layer is mainly composed of high density dislocation entanglement Structure, dislocation, dislocation networks and small residual twins or micro-banded sub-structures formed by dislocation division, and deformable twins and massive sub-structures near the deformation zone are mainly dominated by the analysis. Crystallization is the most critical factor in refining the organization and leading to the conversion of high-energy substructures to nanocrystalline grains.