Toughening mechanism of laminar brittle phases sandwiched by ductile phases

2014 Fiscal Year Final Research Report

• Project/Area Number: 25709066
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: Kyoto University
• Principal Investigator: OKAMOTO Norihiko 京都大学, 工学(系)研究科(研究院), 助教 (60505692)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 微小寸法試料 / 単結晶 / 結晶構造 / 集束イオンビーム(FIB)法 / 走査透過電子顕微鏡 / 異相界面 / 塑性変形 / 正20面体クラスター

Outline of Final Research Achievements

Galvannealed (GA) steels have been widely used in the automobile industry because of their high corrosion resistance, weldability, and paintability. When GA steels are deformed under severe conditions such as press-forming operations, the coating layer occasionally fails by decohesion at the coating－substrate interface. However, the mechanism of the coating decohesion has not been clarified yet. In the present research, we have performed systematic compression deformation experiments of single-phase polycrystalline and single-crystalline micropillars and two-phase micorpillars with one hetero-interface of the five different intermetallic compounds in the iron-zinc system constituting the coating layer of GA steels. We have clarified the fundamental mechanisms of the deformation of the coating layer and proposed a guideline for improving the decohesion-resistance of the coating layer of GA steels.

Free Research Field

金属材料