以工业纯钛为密排六方金属的模型材料.通过多道次冷轧工艺制备具有不同位错界面类型的工业纯钛板材.利用分离式霍普金森压杆(SHPB)实现高速形变,采用透射电子显微分析技术观察位错界面结构的变化,从而分析出不同类型位错界面的高速形变响应.结果表明:在应变速率为1000 s-1时,初始位错界面成为高速形变过程中位错滑移的主要障碍.几何必须位错界面间距为0.5 μm的板材冲击后会出现与原始界面交截的新生位错界面,初始几何必须位错界面(GNB)间距为0.3 μm以下的工业纯钛在高速形变后会出现位错团结构;初始位错界面在0.1μm或以下,局部剪切的组织模式只是初始位错界面的扭折和位错塞积,在高度局域化的组织中,基体扭折位错界面并未产生,但有位错塞积和亚晶结构.
Commercially pure titanium was selected to be a model material.Commercially pure titanium plates with different types of dislocation boundaries were prepared by multi-pass cold rolling.As-impacted titanium samples were obtained by a split Hopkinson pressure bar,and the evolution of dislocation boundary was characterized through transmission electron microscopy.The high-speed deformation response of dislocation boundaries in the commercially pure titanium was launched.Results show that the initial dislocation boundary becomes a major obstacle to dislocation slipping under high-speed compression at the strain rate of 1000 s-1.Plates with geometrically necessary boundaries at the spacing of 0.5 μm can generate new dislocation boundaries intersected with the initial ones aRer high-speed deformation.When the spacing of geometrically necessary boundaries is below 0.3 μm,the dislocation groups form among them.As the spacing of geometrically necessary boundaries declines to 0.1 μm or below,the localized microstructure mode is bending of initial boundary and dislocation groups.There are only dislocation groups and sub-grain in the highly localized zone.
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