Ultimate Tensile Strength Of Welded Joints Research Articles

A Novel Method for Predicting Tensile Strength of Friction Stir Welded AA6061 Aluminium Alloy Joints Based on Hybrid Random Vector Functional Link and Henry Gas Solubility Optimization

Aluminum alloys have low weldability by conventional fusion welding processes. Friction stir welding (FSW) is a promising alternative to traditional fusion welding techniques for producing high quality aluminum joints. The quality of the welded joints is highly dependent on the process parameters used during welding. In this research, a new approach was developed to predict the process parameters and mechanical properties of AA6061-T6 aluminium alloy joints in terms of ultimate tensile strength (UTS). A new hybrid artificial neural network (ANN) approach has been proposed in which Henry Gas Solubility Optimization (HGSO) algorithm has been incorporated to improve the performance of Random Vector Functional Link (RVFL) network. The HGSO-RVFL model was constructed with four parameters; rotational speed, welding speed, tilt angle, and pin profile. The validity of the model was tested, and it was demonstrated that the HGSO-RVFL model is a powerful technique for predicting the UTS of friction stir welded (FSWD) joints. In addition, the effects of process parameters on UTS of welded joints were discussed, where a significant agreement was observed between experimental results and predicted results which indicates the high performance of the model developed to predict the appropriate welding parameters that achieve optimal UTS.

Effects of rotation rate on microstructure and mechanical properties of friction stir-welded Mg-5Al-1Sn magnesium alloy

Mg-Al-Sn magnesium alloys have bright future in application because of good properties without rare earth elements. To study the effects of rotation rate on microstructures and mechanical properties of Mg-5Al-1Sn alloy after friction stir welding (FSW), extruded plates were butt welded by FSW with various rotation rates at constant other parameters. The results showed that after FSW, Mg17Al12 phase with poor thermal stability was dissolved, while Mg2Sn phase remained due to high dissolution point and good thermal stability. The hole-type defects were observed at 600 rpm, and the weld joint was with no defects at 800~1100 rpm. The weld joint at 800 rpm gave a maximum ultimate tensile strength (UTS), which was 91% of the base material (BM). After FSW, both UTS and elongation of weld joints decreased compared with the BM, caused by the soften region between nugget zone (NZ) and thermo-mechanically affected zone (TMAZ), the dissolution of Mg17Al12 phases, the residual stress and dislocation content in the TMAZ, and the textural variation. With increasing rotation rate from 600 to 1100 rpm, the UTS of weld joints first increased and then decreased, while the elongation kept mostly unchangeable due to the common action of multifactors.