MECHANISM OF MICROBAND FORMATION IN COLD ROLLED INTERSTITIAL-FREE STEEL

冷轧无间隙原子钢中的微带生成机理(英文)

The mechanism of the shear band formation in the high cold rolled BCC metal is analyzed. Based on the plastic deformation theory, the shear distribution in the deformed grain is calculated by using the Taylor constraint model and the Bishop ＆ Hill maximum work principle. Results show that when the rolling direction （RD） is parallel to a certain direction of a grain, the large localized shear occurs on one slip plane, thus generating microbands in the grain because of the high localized shear strain. The angle between the RD and the shear band is about 30°. The plate-like structure of the microband is formed because of the dislocation double cross slip. The transmission electron microscope （TEM） observation of the microband in the cold rolled BCC metal confirms the formation mechanism of the microband.

分析了冷轧体心立方金属中微带的形成原因。基于塑性变形理论,运用Taylor模型和Bishop&Hill最大功原理,计算了变形体心立方晶体中滑移系上的切应变分布计算结果表明,冷轧时当晶粒的轧向平行于晶粒的某些特定取向时,大量的局部切应变将集中产生在一个滑移面上并在此形成微带。这一高度局域性的切应变是形成剪切带的原因。此时,剪切带与轧制方向之间夹角为30°。另外,微带呈片状是双交滑移的结果,透射电子显微镜观察到的剪切带所在晶粒的取向和所在滑移面证实了这一微带的形成机制。