On the microstructural evolution pattern toward nano-scale of an AISI 304 stainless steel during high strain rate surface deformation

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2020,（9）
• 页码范围: 148-159
• 页数: 12页
• 语种: 英文

摘要

In the present investigation,an austenitic AISI 304 stainless steel was subjected to high strain rate surface deformation by Pipe Inner-Surface Grinding (PISG) technique.The depth-dependent deformation parameters (strain,strain rate and strain gradient) were evaluated and the microstructures were systematically characterized.Microstructural evolution from millimeter-to nano-scale was explored,with special attention paid to the localized deformation.Microstructural evolution begins with the formation of planar dislocation arrays and the twin-matrix lamellae,which is followed by the localized deformation characterized by the initiation and the development of shear bands.A twinning-dominated process that was supplemented with dislocation slip-dominated one governed the microstructural evolution inside shear bands.The twin-matrix lamellae transform into extended/lamellar structure and finally the nanosized grains.Austenitic grains were substantially refined and martensitic transformation was effectively suppressed,of which the underlying mechanisms were analyzed.