Microstructure and mechanical behaviour of friction stir welded copper

Abstract

The objective of this experimental study was analyzing the joining behavior of 6 mm thick cold rolled copper plate using Friction Stir Welding (FSW) technique. The role of tool rotational speed, travel speed and tool pin profiles on the weld quality, tensile and bend behaviors, hardness, and microstrucuture was investigated. Defect free weld was obtained at tool rotational speeds ranging between 1300 - 1600rpm and welding travel speeds ranging between 30-45mm/min. Tensile strength interms of joint efficiency was found to be 73% compare to the base material (BM). The average hardness of the nugget zone was lesser than the base material because of annealing of the cold rolled copper plates during welding. Different microstructure zones were revealed by optical microscopy (OM). The nugget zone (NZ) and heat affected zone (HAZ) were found to have fine equiaxed grains and fine elongated grains respectively. © 2012 Springer-Verlag.