| Budget Amount *help |
¥16,770,000 (Direct Cost: ¥12,900,000、Indirect Cost: ¥3,870,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2016: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2015: ¥10,530,000 (Direct Cost: ¥8,100,000、Indirect Cost: ¥2,430,000)
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| Outline of Final Research Achievements |
The present project investigated hydrogen-related fracture behavior of martensitic steels by microstructure analysis, three-dimensional fracture surface topography analysis, and hydrogen micro-print technique. The main obtained results are (i) formation site of hydrogen-related cracks is around prior austenite grain boundary in martensite structure, (ii) fracture mechanism changes from plastic strain-controlled to stress-controlled with increasing hydrogen content, (iii) with the proceeding of fracture, the fracture mode changes from intergranular to quasi-cleavage, (iv) hydrogen tends to accumulate around prior austenite grain boundary by tensile deformation at a slow strain rate, (v) hydrogen transportation by dislocation motion is a main mechanism for hydrogen accumulation.
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