Role of tool rotational speed in influencing microstructural evolution, residual-stress formation and tensile properties of friction-stir welded AZ80A Mg alloy

Abstract

Joining flat plates of the AZ80A Mg alloy was carried out using the friction-stir-welding technique, employing various speeds of rotation (the tool), and it was observed that an M-shaped distribution characterizes the stress (residual) distributed in the longitudinal direction. Apart from this, the longitudinal stress (tensile) on the advancing side (AS) was found to be larger than that on the retreating side (RS) in the stir zone. It was experimentally recorded that there seem to be a slight increase in the stress values (tensile longitudinal residual), an increase in the tool rotational speed, and an increase in the peak tensile longitudinal stresses at the edge of the shoulder on the AS of the joints. The grain structures in the stir zone were also found to be influenced by the speed of the tool. Observations of fracture surfaces indicated that dimples and ridges resulted in a ductile fracture and quasi-cleavage resulted in a brittle fracture.

Metallurgical, mechanical and tribological behavior of Reinforced magnesium-based composite developed Via Friction stir processing

“…As a result, it can be concluded that increasing the rotational speed of the FSP tool leads to progressively diminishing strength values, which is consistent with that reported by. 27 In addition, delay in the formation of micro-cracks and their propagation is an outcome of uniformity of microstructure which allows dislocation slips to occur easily. 28 Also, FSP caused anisotropy in tensile properties with a higher level of anisotropy in multiple passes.…”

Development of Thermo Mechanical Model for Prediction of Temperature Diffusion in Different FSW Tool Pin Geometries During Joining of AZ80A Mg Alloys

“…In this experimental research, anticipated peak temperature Tmax was validated against experimentally measured temperature values and found to coincide with one another. Results of experimental runs carried out at the optimised process parameter conditions (i.e, tool rotational speed = 818 rpm; force applied on the FSW tool axially = 3.64 kN; rate of traversing of tool over workpiece = 1.48 mm/s) were taken as the inputs for generating line plots and contours [3,44]. The variations of temperature on the surface of the workpiece w.r.t the offset lines and bonding lines, when the tool approaches the workpiece centre part, for the various employed FSW tools with the different pin geometries are illustrated in the Figure 7 Figure 8 decribes in detail, the generated temperature contour graphs on the top surfce of the work piece and on the bonding surfaces for tools with different pin geometries.…”

Development of Thermo Mechanical Model for Prediction of Temperature Diffusion In Different Fsw Tool Pin Geometries During Joining of Az80A Mg Alloys

“…In this experimental research, anticipated peak temperature Tmax was validated against experimentally measured temperature values and found to coincide with one another. Results of experimental runs carried out at the optimised process parameter conditions (i.e, tool rotational speed = 818 rpm; force applied on the FSW tool axially = 3.64 kN; rate of traversing of tool over workpiece = 1.48 mm/s) were taken as the inputs for generating line plots and contours [3,44]. The variations of temperature on the surface of the workpiece w.r.t the offset lines and bonding lines, when the tool approaches the workpiece centre part, for the various employed FSW tools with the different pin geometries are illustrated in the Figure 7 (a) & (b).…”