A review: Suppression of the solidification cracks in the laser welding process by controlling the grain structure and chemical compositions

Laser beam welding of miscellaneous material combinations is an effective joining technology useful for diverse industrial applications because it can provide high speed, flexibility, and precision. However, welding defects like solidification cracking are some of the challenges in the joining process. The past decade has seen an extended effort to deal with this issue in many studies. However, there remains to be more comprehensive research regarding preventive procedures for solidification cracking by changing the grain structure. Following a thorough understanding of the solidification crack mechanism theories, we reviewed recent research on the critical role of metallurgical factors in the solidification cracks during laser welding. It considers the influence of the grain structure, intermetallic compounds, and laser welding parameters to propose preventive procedures to suppress the solidification cracks. Recent achievements show grain refiners, laser beam oscillation, ultrasonic vibration, and implementation of double laser sources are the main strategies that suppress or minimize solidification cracks. Furthermore, in laser beam welding of dissimilar materials, like steel-hard metal and copper-aluminum, brittle intermetallic compounds are recognized as one of the main reasons for the solidification crack susceptible increment. Recent approaches to overcome the formation or reduce the number of intermetallic compounds through various laser parameters and setups are discussed.