Materials science and design by grain boundary engineering

2014 Fiscal Year Final Research Report

• Project/Area Number: 24246117
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Material processing/treatments
• Research Institution: Tohoku University
• Principal Investigator: KOKAWA HIROYUKI 東北大学, 工学(系)研究科(研究院), 教授 (10133050)
• Co-Investigator(Renkei-kenkyūsha): SATO Yutaka 東北大学, 大学院工学研究科, 准教授 (00292243) ; FUJII Hiromichi 東北大学, 大学院工学研究科, 助教 (70560225)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 粒界工学 / オーステナイト系ステンレス鋼 / ニッケル合金 / 粒界劣化 / 対応粒界 / 加工熱処理 / 粒界腐食 / 粒界性格分布

Outline of Final Research Achievements

Austenitic stainless steels and nickel alloys have high corrosion resistance and high temperature strength, but intergranular degradations are their conventional and momentous problems. Grain boundary engineering (GBE) can suppress these intergranular degradations by introducing high frequency of coincidence site lattice boundaries into the materials. The authors developed a single-step thermomechanical process for GBE and produced highly intergranular degradation resistant materials by the GBE processing. The grain boundary engineered materials (GBEMs) demonstrated more excellent properties, higher reliability, and longer life than the unGBEed ones. The superiority of GBEMs was confirmed even during manufacturing by examining stabilities of optimized GBEed microstructures and GBE effects by post-GBE straining and sensitization. This study has established the mechanism of GBE effects and the optimization of grain boundary character distribution.

Free Research Field

材料工学