Harmonic structure formation and deformation behavior in a (α + γ) two phase stainless steel

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Ota, M.^1 ; Sawai, K.^2 ; Kawakubo, M.^2 ; Vajpai, S.K.^1 ; Ameyama, K.^3

Research Organization of Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan^1

Graduate School of Mechanical Engineering, Ritsumeikan University, Shiga 525-8577, Japan^2

Faculty of Mechanical Engineering, Ritsumeikan University, Shiga, Japan^3

关键词: Deformation behavior;    Dislocation cell structures;    Harmonic structures;    High strength and high ductilities;    Mechanical milling;    Nano-crystalline structures;    Networked structures;    Stainless steel powders;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012027/pdf
DOI  :  10.1088/1757-899X/63/1/012027

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In the present work the harmonic structure design has been successfully applied for achieving a combination of high strength and high ductility, simultaneously, in a two-phase steel. The compacts of two-phase stainless steels with harmonic structure were prepared by controlling mechanical milling (MM) of pre-alloyed stainless steel powders followed by spark plasma sintering. The controlled MM leads to the formation of severely deformed "shell" region, wherein the subsurface region in the immediate vicinity of the powder surface consists of a nanocrystalline structure followed by the inner region consisting of dislocation cell structure. These severely deformed regions form fine-grained network during subsequent sintering, resulting in Harmonic structure. This networked structure displayed high strength, high ductility, and better uniform plastic deformation as compared to the homogeneous fine/coarse grained structure. Such a unique combination of properties in the two-phase stainless steel powder compacts was found to be associated with the ability of the harmonic structure to evenly distribute the strain during plastic deformation.