Microhardness study on autogenous lap joint between titanium and nickel alloys with low power fiber laser

• Main Authors: Janasekaran, Shamini, Rony, Md. Mehedy Hasan, Yusof, Farazila, Bushroa, Abd Razak
• Format: Conference Proceeding
• Language: English
• Subjects: Base metal; Diamond pyramid hardness; Dissimilar materials; Fiber lasers; Hardness measurement; Heat affected zone; Lap joints; Laser beam welding; Lasers; Microcracks; Nickel base alloys; Titanium base alloys
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0188297

Welding is described as a technique of fabricate to join two or more segments either similar or dissimilar materials. Welding procedure divided to two classifications, consists of combination welding and strong state welding process. In this research, low power fiber laser welding was used to weld two different metals using lap joint technique. The study focusses on Ti6Al4V and Inconel 600 without filler alloy in between. Influences of laser welding speed (15mm/s up to 21mm/s) and laser power (230W up to 250W) with constant focal distance were examined on the weldment microhardness. The hardness of the joints was analyzed using Vickers hardness measurement at the base metal (BM), fusion zone (FZ) and heat-affected zone (HAZ). Results showed that as the welding speed decreases and laser welding power increases, the microhardness at HAZ is the highest followed by FZ. The optimum microhardness was achieved at 240W and 15mm/s. However, the higher the laser power goes, possibility of micro-cracks and void to happen increases which can lead to reduction in microhardness. The conclusion is that optimum laser welding power and welding speed is essential to make sure sound joint can be produced.