| Budget Amount *help |
¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2013: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2012: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Outline of Final Research Achievements |
A new bonding technique of titanium and zirconium conducted at low temperatures was developed utilizing the hydrogen-induced transformation. Titanium and zirconium hydrides were formed at faying surfaces after hydrogen charge treatment. The β-transus temperature at faying surfaces of titanium and zirconium was reduced to approx. 450-550C with hydrogen-charging. Grain growth across the prior bond interface was observed in the joints bonded at 750-800C after hydrogen-charging for 300-500ks. Tensile strength of titanium joints bonded at 800C attained approx. 70% of the base metal strength (approx. 1.6 times as high as non-charged joints), and corrosion resistance of the joints was comparable to that of the base metal. Furthermore, tensile strength of zirconium joints bonded at 800C was approx. 1.7 times as high as non-charged joints. It follows that the solid-state bondability of titanium and zirconium at low temperatures was improved compared to the conventional diffusion bonding.
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