大塑性变形过程中IF钢的组织演变

在室温下，使用半连续等通道挤压法对单块IF钢试样进行重复大变形实验，通过电子背散射衍射方法，对在此晶粒细化过程中的材料组织进行了分析讨论.结果表明，在不同挤压道次中组织变形主要发生在沿两通道连接的剪切面上，且材料由切应变产生塑性变形，挤压后的试样组织在横截面上应力保持一致；随着应变的增加，材料的组织细化不断加强；10道次后，最终的大角度晶界(HAB)占总数的90%左右，同时大角度晶界的间隙减少到1μm左右，试样的平均晶粒尺寸达到055μm左右.

Microstructure Evolution During Severe Plastic Deformation of IF Steel

Severe plastic deformation of IF steel was repeatedly carried out at room temperature by using semi continuous equal channel angular extrusion(SC ECAE). The microstructures evolution and the mechanisms of grain refinement during deformation were analyzed by EBSD. The results showed that the deformation primarily takes place in simple shear along the intersectional plane of the two extrusion channels， the plastic deformation is caused by shear strain， and the stress of deformation structures is reasonably uniform over the whole cross section of the workpiece. The grain refinement is strengthened with the increase of strain. The final HAB fraction of about 90% is obtained and the HAB spacing decreases to less than 1μm，and the overall grain size decreases to about 055μm after 10 passes.