Development of toughness and creep strength of B added transition metal disilicides with lamellar structure

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K18261
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: Niihama National College of Technology (2017-2018); Osaka University (2016)
• Principal Investigator: Todai Mitsuahru 新居浜工業高等専門学校, 環境材料工学科, 准教授 (10610800)
• Research Collaborator: Nakano Takayoshi
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 遷移金属シリサイド / クリープ特性 / 超高温構造材料 / 単結晶育成 / 結晶方位 / 環境

Outline of Final Research Achievements

The present study clarified the influence of B addition on the C40 / C11b lamellar structure in transition-metal disilicides and the contribution to mechanical properties such as room temperature toughness and high temperature creep property. From this study, the following findings were obtained. 1) B-addition led to an increasing in the volume fraction of the C11b phase having secondary-variant orientation relationship, accompanied by the reduction in their growth rate. 2) It was found that this varied microstructure drastically improved the fracture toughness of the duplex crystal, exhibiting the highest value of ~4.5 MPa m1/2 in the three-point bending test. 3) B added transition-metal disilicides exhibit an anisotropy of creep strength.

Free Research Field

材料強度学

Academic Significance and Societal Importance of the Research Achievements

航空機等の輸送機関の高速化および発電用タービンの燃焼効率の改善には、ガス燃焼温度の増大は不可欠であるが、現在のNi基超合金製タービン翼の使用限界温度は1000°C付近であり、その開発が限界にある近づきつつある。高融点シリサイドの室温靭性と高温クリープ特性の向上は、実用化に至っていない遷移金属シリサイド結晶の将来的な実用化に向けたキーテクノロジーとして大きく寄与すると考えられ、その潜在的価値は非常に大きい。