Development of multi-phase steels with fine and complicated 3-dimensional continuous structure by controlling martensitic transformation

2016 Fiscal Year Final Research Report

• Project/Area Number: 26709054
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Material processing/Microstructural control engineering
• Research Institution: The University of Tokyo
• Principal Investigator: NAMBU Shoichi 東京大学, 工学(系)研究科(研究院), 講師 (00529654)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 組織制御 / マルテンサイト変態 / 鉄鋼材料 / オーステナイト / その場観察 / 結晶方位解析

Outline of Final Research Achievements

To develop a multi-phase steels with 3-dimensinal continuous structure having improved strength and ductility combinations, we aimed to propose the principles to control the microstructures and improve the mechanical properties. The evolution process of microstructure during martensitic transformation, especially in the early stage, was investigated by in-situ observation. It was demonstrated that the process depends on the carbon contents that is the yield stress of austenite phase. The thermal process was proposed to stabilize the austenite phase by promoting the carbon diffusion, and the deformation induced transformation is expanded to relatively high strain range by uniforming the carbon distribution in austenite phase. Also the affecting factors to deformation induced transformation was investigated by in-situ EBSD observation.

Free Research Field

材料組織制御工学