2012 Fiscal Year Final Research Report

Creation of precipitation hardened surface ceramics layer aiming to develop innovative steels with high wear resistance

Research Project

Project/Area Number	24656397
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Structural/Functional materials
Research Institution	Tohoku University
Principal Investigator	MIYAMOTO Goro 東北大学, 金属材料研究所, 准教授 (60451621)
Project Period (FY)	2012
Keywords	鉄鋼材料 / 表面硬化処理 / ナノ析出 / 析出強化
Research Abstract	In order to create surface ceramics layer hardened by nano-sized precipitate, pure Fe and Fe-M binary alloys containing small amount of nitride forming elements were gaseous nitrided and crystal structure, growth rate and hardness of surface layer wereinvestigated. Nano-indentation measurements revealed that hardness of γ' layer on the surface of pure Fe is much higher than those in ferrite matrix beneath γ'. On the other hand, hardness of ferrite after nitriding treatment is significantly increased by the addition of Cr, V or Al, while alloying effect on hardness of compound layer is relatively small. Those results imply that precipitation hardening by nano-sized nitrides is not so effective to harden the compound layer.