Characterization of degradation of material strength properties in high-temperature hydrogen environment for ensuring safety of advanced hydrogen utilization systems

• Project/Area Number: 16H04237
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Kyushu University
• Principal Investigator: Kubota Masanobu 九州大学, カーボンニュートラル・エネルギー国際研究所, 教授 (50284534)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥18,070,000 (Direct Cost: ¥13,900,000、Indirect Cost: ¥4,170,000); Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2016: ¥14,690,000 (Direct Cost: ¥11,300,000、Indirect Cost: ¥3,390,000)
• Keywords: 水素脆化 / 高温 / クリープ / 環境強度 / 水素 / 材料力学・機械材料学 / 次世代水素利用 / 機械材料・材料力学 / 次世代水素利用機器 / 高温水素環境

Outline of Final Research Achievements

Use of hydrogen as an energy carrier is promoted as one of the ways toward low-carbon society. The target of this study was characterization of material strength properties in hydrogen gas at elevated temperature. The test environment assumed advanced energy conversion system such as reversible fuel cell.
The accomplishments of this study are as follows: (1) A testing machine that enables material testing in hydrogen gas at 600 deg C was developed. (2) A test protocol for safe implementation of material testing in high-temperature hydrogen gas was established. (3) Slow strain rate testing was carried out in Ar and hydrogen gases at the temperature range from room temperature to 600 deg C. And then, the material strength properties were characterized in each environment. The materials were SUS304 austenitic stainless steel and Ti-6Al-4V. (4) Creep data of SUS304 in Ar and H2 at 600 deg C were obtained.Reduction in the creep life in H2 was confirmed.

Academic Significance and Societal Importance of the Research Achievements

温室効果ガスの削減は世界中の国々とって大きな課題であり，CO2排出抑制策として炭素税や石油・石炭・天然ガスなどに対するエネルギー税の賦課が考えられている．このことは，企業の生産活動に対して重荷となる可能性があり，低炭素技術の確立が急務である．水素利用は低炭素化の一つの方向性であり，本研究では，高温水素中で動作するデバイスを想定し，その環境で生じる材料損傷の基礎的な研究を実施た．本研究により，高温水素中の構造材料の研究を実施する環境を世界に先駆けて確立した．水素中のクリープ寿命が低下する現象を確認し，また，高温でも水素が材料の変形挙動に影響を与えることを明らかにした．