scholarly journals Mechanical Property Improvement in Dissimilar Friction Stir Welded Al5083/Al6061 Joints: Effects of Post-Weld Heat Treatment and Abnormal Grain Growth

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 288
Author(s):  
Amir Hossein Baghdadi ◽  
Zainuddin Sajuri ◽  
Azadeh Keshtgar ◽  
Nurulakmal Mohd Sharif ◽  
Armin Rajabi
Keyword(s):  
Heat Treatment ◽  
Mechanical Property ◽  
Grain Growth ◽  
Precipitation Hardening ◽  
Welded Joint ◽  
Abnormal Grain Growth ◽  
Post Weld Heat Treatment ◽  
Welding Parameters ◽  
Friction Stir ◽  
Weld Heat

The 5083 and 6061(T6) aluminum (Al) alloys are widely used in transportation industries and the development of structural designs because of their high toughness and high corrosion resistance. Friction stir welding (FSW) was performed to produce the dissimilar welded joint of Al5083-Al 6061(T6) under different welding parameters. However, softening behavior occurred in the friction stir welded (FSWed) samples because of grain coarsening or the dissolution of precipitation-hardening phases in the welding zone. Consequently, this research intended to investigate the effect of the post-weld heat treatment (PWHT) method on the mechanical property improvement of the dissimilar FSWed Al5083-Al6061(T6) and governing abnormal grain growth (AGG) through different welding parameters. The results showed PWHT enhanced the mechanical properties of dissimilar joints of Al5083-Al6061(T6). AGG was obtained in the microstructure of PWHTed joints, but appropriate PWHT could recover the dissolved precipitation-hardening particle in the heat-affected zone of the as-welded joint. Further, the tensile strength of the dissimilar joint increased from 181 MPa in the as-welded joint to 270 MPa in the PWHTed joint, showing 93% welding efficacy.

scholarly journals Friction Stir Welding Parameters: Impact of Abnormal Grain Growth during Post-Weld Heat Treatment on Mechanical Properties of Al–Mg–Si Welded Joints

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1607
Author(s):  
Amir Hossein Baghdadi ◽  
Zainuddin Sajuri ◽  
Mohd Zaidi Omar ◽  
Armin Rajabi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Friction Stir Welding ◽  
Grain Growth ◽  
Precipitation Hardening ◽  
Al Alloys ◽  
Abnormal Grain Growth ◽  
Post Weld Heat Treatment ◽  
Welding Parameters ◽  
Friction Stir

Friction stir welding (FSW) is an alternative method to join aluminum (Al) alloys in a solid-state condition. However, the coarsening or dissolution of precipitation hardening phases in the welding zone causes strength reduction or softening behavior in the welded area of age-hardened Al alloys. Therefore, this research aimed to improve the mechanical properties of an FSW Al–Mg–Si alloy via post-weld heat treatment (PWHT) and the possibility of controlling the abnormal grain growth (AGG) using different welding parameters. FSW was performed with different rotational and travel speeds, and T6 heat treatment was carried out on the FSW samples as the PWHT. The results showed a decrease in the strength of the FSW samples compared with that of the base material (BM) due to the dissolution of precipitation hardening particles in the heat-affected zone. However, the emergence of AGG in the microstructure after the T6-PWHT was identified as the potential event in the microstructure of the PWHT samples. It is found that the AGG of the microstructure in similar joints of Al6061(T6) was governed by the welding parameters. The results proved that PWHT was able to increase the tensile properties of the welded samples to values comparable to that of Al6061(T6)-BM. The increased mechanical properties of the FSW joints were attributed to a proper PWHT that resulted in a homogeneous distribution of the precipitation hardening phases in the welding zones.

scholarly journals The Influence of Post-Weld Heat Treatment on the Microstructure and Fatigue Properties of Sc-Modified AA2519 Friction Stir-Welded Joint

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 583 ◽  
Author(s):  
Robert Kosturek ◽  
Lucjan Śnieżek ◽  
Marcin Wachowski ◽  
Janusz Torzewski
Keyword(s):  
Heat Treatment ◽  
Precipitation Hardening ◽  
Low Cycle Fatigue ◽  
True Strain ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Fatigue Properties ◽  
Friction Stir ◽  
Scanning Electron ◽  
Weld Heat

The aim of this research was to investigate the influence of post-weld heat treatment (PWHT, precipitation hardening) on the microstructure and fatigue properties of an AA2519 joint obtained in a friction stir-welding process. The welding process was performed with three sets of parameters. One part of the obtained joints was investigated in the as-welded state and the second part of joints was subjected to the post-weld heat treatment (precipitation hardening) and then investigated. In order to establish the influence of the heat treatment on the microstructure of obtained joints both light and scanning electron microscopy observations were performed. Additionally, microhardness analysis for each sample was carried out. Fatigue properties of the samples in the as-welded state and the samples after post-weld heat treatment were established in a low-cycle fatigue test with constant true strain amplitude equal to ε = 0.25% and cycle asymmetry coefficient R = 0.1. Hysteresis loops together with changes of stress and plastic strain versus number of cycles are presented in this paper. The fatigue fracture in tested samples was analyzed with the use of scanning electron microscope. Our results show that post-weld heat treatment of AA2519 friction stir-welded joints significantly decreases their fatigue life.

Effect of post weld heat treatment and welding parameters on mechanical and corrosion characteristics of friction stir welded aluminium alloy AA2014-T6

2019 ◽  
Vol 43 (2) ◽  
pp. 230-236
Author(s):  
Ashok S. Kannusamy ◽  
Ravindran Ramasamy
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Welding Parameters ◽  
Friction Stir ◽  
Heat Treated ◽  
Ageing Period ◽  
Weld Heat

This paper addresses the effect of post weld heat treatment methods on the mechanical and corrosion characteristics of friction stir welded aluminum alloy AA2014-T6. Aluminum alloy AA2014 is mainly used in applications that demand high strength to weight ratios, such as aerospace, marine, and industrial applications. In this work, AA2014-T6 plates of 6 mm thick were butt welded using a tool with a square profile. Tensile strength, hardness, and corrosion characteristics were compared between the samples as welded and post weld heat treated. Welded samples that were heat treated for a shorter ageing period (8 h) showed improved tensile strength irrespective of welding process parameters, compared to as-welded samples. The samples heat treated for a longer ageing period (9 h) showed a decline in tensile strength for low tool rotation speed. Hardness increased in welded samples heat treated for 8 h. Welded samples heat treated for 9 h show high passivity in corrosion media.

scholarly journals Effects of Laser Welding and Post-Weld Heat Treatment on Microstructure and Mechanical Properties of Aged Ti55531 Alloy

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1907 ◽  
Author(s):  
Lin-Jie Zhang ◽  
Jun-Yu Pei ◽  
Jian Long ◽  
Miao-Xia Xie ◽  
Xiang-Tao Shang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Welded Joint ◽  
Orthogonal Experiment ◽  
Laser Beam Welding ◽  
Tensile Tests ◽  
Post Weld Heat Treatment ◽  
Welding Parameters ◽  
Α Phase ◽  
Weld Heat

As one of the relatively new titanium (Ti) alloys in the engineering field, β-Ti alloy–Ti55531 has attracted a great deal of attention due to its excellent mechanical properties, while a few research papers on weldability and the post-weld heat treatment (PWHT) process of Ti55531 have been reported. Based on an orthogonal experiment design, the parameters of laser beam welding (LBW) of Ti55531 alloy with a thickness of 2 mm were optimized. Moreover, the influences of welding parameters and PWHT on the microstructures and performance of the laser-welded joint of Ti55531 were analyzed. The results showed that, for microstructures in different zones of as-welded joints of Ti55531: three forms of α phases (i.e., equiaxial αp phase, lamellar αS phase, and αGB phase at grain boundaries) were observed in base metal (BM); in the heat affected zone (HAZ), part of lamellar αS phase had dissolved while equiaxial αp phase had grown; the fusion zone (FZ) mainly consisted of β phase, which presented as coarse columnar crystals. After the PWHT process, the microstructures of the welded joint were changed: in the BM zone, α phase at grain boundary disappeared and lamellar α phase decreased; in the HAZ, the edge of αp phase obviously dissolved; in the FZ, plenty of compact needle-like α phases were observed. The tensile strength of the as-welded joint was about 940 MPa and then increased to 1161 MPa after PWHT, which were 78.4% and 96.8% of that of the original BM respectively. The fracture position transformed from the interface between the FZ and HAZ to the BM during tensile tests after PWHT.

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