9. Effect of Cryogenic Coolant on Mechanical Properties and Micrographs of Solid State Welding of 2014 Al Plates

Solid (Friction) stir welding (FSW) is a moderately new welding practice, and it is a widely adopted process used to join metallic alloys. It is a fad in automobile, aerospace, and further manufacturing concern for linking complex geometry of joints. The present research paper, the influence of cryogenic cool (dry ice and liquid nitrogen) on grain refining and tensile and microhardness property of 2014 Al FSWed is demonstrated. Cryogenic coolant process was employed in friction stir welding to reduce the grain size that observed by using an optical microscope as 2–4 µm (average size) and to improve the mechanical properties which are obtained higher properties with tool shoulder diameter of 24 mm, taper cylindrical thread pin profile at a rotational speed of 900 rpm, and a welding speed of 60 mm/min due to equiaxed grains of FSWed 2014 aluminum alloy. By cryogenic process, it is observed that mechanical properties are enormously improved. Scanning electron microscopy (SEM) helps for the quality and high-resolution fractography analysis of a cryogenic-processed FSWed Al 2014 plates.