A study on mechanical properties in friction stir lap welding of AA 6061-T6 and AISI 304

A review on friction-based joining of dissimilar aluminum–steel joints

“…Majority of literature studies related to Al-steel FSW have suggested that the IMC layer ,5 lm can report better joint properties. 3,6,53,[67][68][69][70][71][72][73][75][76][77][78][79]83,122 Larger thickness of IMCs always deteriorates the mechanical properties of the joint that is evidenced in the case of Al-steel FSW in number of articles. 69,106,113,123 The phases developed in the case of FSW are because of solid state diffusion with metal to metal interactions, interreaction with phases and lowest eutectic compositions, and inter reactions of phases and Fe.…”

“…Pin offset in Al leads to major plastic deformation of the Al material while partial deformation of the steel material, which causes the dispersion of steel particles and that consequently lead to mixing of steel particles into the Al matrix. 1,25,55,[69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88] The size of these steel particles are dependent on tool pin offset majorly as well as heat input given by the process parameters of rotational speed, travel speed, and tool design. Another important parameter is the position of the workpiece, 1,53,89,90 wherein, effective material flow and enhanced mixing can be obtained when steel is kept at the advancing side and Al at the retreating side.…”

“…The nonconsumable tool is having important elements such as pin diameter/dimensions, pin shape feature, shoulder diameter, shoulder surface geometry, shoulder to pin diameter ratio, and pin length that need to be fixed in such a way that effective dissimilar joint of Al-steel can be obtained. 3,55,[69][70][71][72][73][74][75][77][78][79][80][81]85, Shoulder diameter, its surface area, and shoulder to pin diameter ratio contribute maximum to the heat input that in turn influences joint formation. Pin dimensions and its features decide the material flow.…”

“…In 69,106,113,123 The thickness of the IMC layer at the interface is reported in the range of ,0.1 lm-58.1 lm. 3,6,53,[67][68][69][70][71][72][73][75][76][77][78][79]83,122 Thickness of IMCs in the Al-steel FSW system is governed by shoulder diameter, shoulder to pin diameter ratio, rotational speed, and travel speed as heat input is largely influenced by these parameters. Rest of the parameters of FSW such as tool pin offset, material position, and axial pressure play significant role for the proportion of Al and steel interaction and hence IMCs are also influenced by them.…”

“…Mechanical properties such as tensile properties and hardness are studied in majority of the literature studies. 3,6,53,[67][68][69][70][71][72][73][75][76][77][78][79]83,122 These properties are greatly influenced by the mixing of Al and Fe fragments that is governed by FSW process parameters. High heat input conditions such as too low travel speed, very high rotational speed, and large shoulder diameter cause more material deformation that in turn detaches large fragments of Fe particles, which is difficult to mix with the Al matrix and results into the defects (such as voids and cracks).…”