Development of short-pulse laser induced-pressure wave-assisted laser welding method based on a novel scientific principle of controlling metal microstructures

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H02048
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Osaka University
• Principal Investigator: Sano Tomokazu 大阪大学, 大学院工学研究科, 教授 (30314371)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: レーザ溶接 / 短パルスレーザ誘起圧力波 / 金属組織制御

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.

Free Research Field

材料加工学

Academic Significance and Societal Importance of the Research Achievements

本手法は、微粒化材を添加することなく、高速レーザ溶接における凝固割れを抑制できる可能性がある。本手法を用いてアルミニウム合金溶接部の凝固組織を改善することで、信頼性の高い高速レーザ溶接が可能となり、アルミニウム合金の応用範囲が広がる。