M. Belbasi, M. Rezae,
Volume 5, Issue 2 (1-2020)
Abstract
Today in addition to Join by friction stir welding, the composite fabrication process is also performed simultaneously. The main purpose of the present research is to investigate the effect of pin geometry on the property of Aluminum 6061- alumina nanocomposite created by friction stir welding. For this purpose friction stir welding was carried out by selecting five types of pin geometries on Aluminum 6061 in which Al2O3 particles were deposited and the samples were examined by tensile and hardness tests, optical and electron microscope. Samples were investigated by tensile and hardness test, optical and electronic microscopy. Regular hexagonal pins due to having six smooth face and impulsive movement during rotation, caused a good perturbation which resulted in maximum tensile strength and elongation percentage of 198 MPa and 10.25 and minimum grain size of 13.3 micron, respectively. In the sample welded by a threaded cylindrical pin due to non-impact during rotation, inappropriate flow of reinforcing particles and its accumulation at perturbation the lowest tensile strength and elongation percentage of 133.5 MPa and 1.95%, respectively, were observed.
M. Alimadadi, M. Goodarzi, S.m.a. Boutorabi,
Volume 7, Issue 1 (8-2021)
Abstract
This present study aimed to create an Al6061-St52 dissimilar joint and investigate the effect of the transverse speed by the friction stir welding process. Welding aluminum to steel is rugged by fusion methods because of the formation of brittle intermetallic compounds (IMCs). Therefore, to designate optimal parameters, acceptable IMC thickness, and mechanical properties determined. This research carried out different three transverse speeds of 16, 40 and 85 mm/min (with a constant pin offset of 0.2 mm). Geometry of tool's pin radius and height is 4mm and 1.8mm, respectively. In the transverse speed parameter, the highest ultimate tensile strength (UTS) of 200 MPa was obtained at 85 mm/min. According to the Energy Dispersive X-ray Spectroscopy results, an IMC layer formed in the joint interface. The heat input rate was calculated to designate the optimal parameters. In tensile specimens, fracture mainly occurred in the joints and within the aluminum stir zone due to the combination of thick IMC layer and steel fragments, respectively. The micro-hardness measurement results showed that at (85 mm/min) the hardness values were HV 75 in the aluminum stir zone and HV 315 in the AS vicinity of the interface region. This hardness value is much higher than the base metals (Aluminum base metal is an average of HV 53 and an average steel base metal of HV 245).
