| Budget Amount *help |
¥17,810,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥4,110,000)
Fiscal Year 2023: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2022: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2021: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2020: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000)
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| Outline of Final Research Achievements |
By performing short-pulse laser ablation during laser welding, the crystal grains of 2024 aluminum alloy weld metal, which is generally considered to have a high susceptibility to cracking, were refined and the progression of solidification cracking was successfully suppressed. Vickers hardness test results confirmed that the hardness increased due to the effect of grain refinement. Since the pressure wave generated by the short-pulse laser exceeded the dendrite intensity in the high-temperature state, the increase in equiaxed crystal formation sites due to dendrite crushing is considered to be one of the grain refinement mechanisms. From the experimental results, it is concluded that grain refinement is based on two mechanisms: dendrite crushing and dynamic nucleation.
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