Microstructural and mechanical properties of friction-stir-welded and post-heat-treated Inconel 718 alloy

2010 ◽  
Vol 505 (1) ◽  
pp. 144-150 ◽  
Author(s):  
K.H. Song ◽  
K. Nakata
2011 ◽  
Vol 1363 ◽  
Author(s):  
Kuk Hyun Song ◽  
Han Sol Kim ◽  
Won Yong Kim

ABSTRACTIn order to investigate the formation of precipitates such as MC carbides and intermetallic compounds in the friction stir welded and post-heat-treated Inconel 718 alloy, this work was carried out. Furthermore, the microstructural and mechanical properties of welds and post-heat-treated material were evaluated to identify the effect on precipitates formed during post-heat-treatment. Friction stir welding (FSW) was performed at a rotation speed of 200 rpm and welding speed of 150 mm/min; heat treatment was performed after welding at 720 °C for 8 hours in vacuum. As a result, the grain size due to FSW was notably refined from 5–20 μm in the base material to 1–3 μm in the stir zone; this was accompanied by dynamic recrystallization, which resulted in enhancements in the mechanical properties as compared to the base material. In particular, applying heat treatment after FSW led to improvements in the mechanical properties of the welds—the microhardness and tensile strength increased by more than 50% and 40% in fraction, respectively, as compared to FSW alone.


Author(s):  
Ajay Kumar Maurya ◽  
Amit Kumar

Additive manufacturing technology is becoming popular in the industry because it allows the manufacturer to fabricate cost-effective, strong, lightweight, and complex-shaped parts directly from 3D design data as compared with the conventional manufacturing method. Inconel 718 alloy is the most demanding material in aviation as well as in the automobile industry, in terms of manufacturing high-performance parts. In this study, Inconel 718 samples were built using the direct metal laser sintering process, and standard heat treatment was performed on the samples to improve their microstructure and mechanical properties. The as-built samples exhibited good grain structure with fine laves phases, but the matrix was free from ?' and ?" phases. During the heat treatment, the strengthening phases ?' and ?" precipitated. The mechanical properties of as-built and heat-treated samples were analysed and compared. Tensile tests revealed that the direct-aged sample had the higher tensile strength compared with the other conditions, whereas the as-built samples had higher ductility. Finally, fractography and microstructure analysis were performed to measure the failure modes of tensile specimens.


Materialia ◽  
2021 ◽  
pp. 101187
Author(s):  
Alexandre Balan ◽  
Michel Perez ◽  
Thibaut Chaise ◽  
Sophie Cazottes ◽  
Didier Bardel ◽  
...  

2021 ◽  
Vol 875 ◽  
pp. 203-210
Author(s):  
Talha Ahmed ◽  
Wali Muhammad ◽  
Zaheer Mushtaq ◽  
Mustasim Billah Bhatty ◽  
Hamid Zaigham

In this study, mechanical properties of friction stir welded Aluminum Alloy (AA) 6061 in three different heat treatment conditions i.e. Annealed (O), Artificially aged (T6) and Post Weld Heat Treated (PWHT) were compared. Plates were welded in a butt joint form. Parameters were optimized and joints were fabricated using tool rotational speed and travel speed of 500 rpm and 350 mm/min respectively. Two sets of plates were welded in O condition and out of which one was, later, subjected to post weld artificial aging treatment. Third set was welded in T6 condition. The welds were characterized by macro and microstructure analysis, microhardness measurement and mechanical testing. SEM fractography of the tensile fracture surfaces was also performed. Comparatively better mechanical properties were achieved in the plate with PWHT condition.


Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1024 ◽  
Author(s):  
Robert Kosturek ◽  
Lucjan Śnieżek ◽  
Janusz Torzewski ◽  
Marcin Wachowski

The aim of this research was to investigate the effect of friction stir welding (FSW) parameters on microstructure and mechanical properties of Sc-modified AA2519 extrusion joints. The workpiece was welded by FSW in non-heat-treated condition with seven different sets of welding parameters. For each obtained joint macrostructure and microstructure observations were performed. Mechanical properties of joints were investigated using tensile test together with localization of fracture location. Joint efficiencies were established by comparing measured joints tensile strength to the value for base material. The obtained results show that investigated FSW joints of Sc-modified AA2519 in the non-heat-treated condition have joint efficiency within the range 87–95%. In the joints obtained with the lowest ratio of the tool rotation speed to the tool traverse speed, the occurrence of imperfections (voids) localized in the stir zone was reported. Three selected samples were subjected to further investigations consisting microhardness distribution and scanning electron microscopy fractography analysis. As the result of dynamic recrystallization, the microhardness of the base material value of 86 HV0.1 increased to about 110–125 HV0.1 in the stir zone depending on the used welding parameters. Due to lack of the strengthening phase and low strain hardening of used alloy the lack of a significantly softened zone was reported by both microhardness analysis and investigation of the fractured samples.


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