Control of the high speed plastic properties by the phase boundaries in FCC+BCC multi phased steels

本研究旨在阐明铁素体和奥氏体双相钢在高速变形下的塑性性能。用传感块式试验机在0.001/s ~ 1000/s的应变速率下测量了应力-应变曲线。结果表明，随着应变速率的增加，双相钢的偏置应力显著增加0.2%。采用电子背散射衍射（EBSD）测量了在不同应变速率下变形到不同应变的样品。研究了相界附近的位错测量，阐明了局部位错的优先发展规律。这意味着在相界附近可以很容易地形成提供远程应力场的位错结构。此外，还发现了动态相变与位错结构之间的关系。

This study is aimed to clarify the plastic properties of the ferrite and austenite duplex phase steels at high speed deformation. The stress - strain curves were measured with the sensing block type testing machine at various strain rate ranging from 0.001/s to 1000/s. It was clarified that the duplex phase steel has a significant increase of 0.2% offset stress with the strain rate increasing. The EBSD (Electron back scattering diffraction) measurement was conducted on the samples deformed up to various strain at various strain rate. The misorientation measurement at the vicinity of the phase boundaries were examined and the preferential development of the local misorientation was clarified. This means that the dislocation structure which provides the long range stress field can be easily evolved near the phase boundaries. In addition, the relationship between the dynamic phase transformation and the dislocation structure was also found.