Strengthening mechanism of friction stir processed and post heat treated NiAl bronze alloy: Effect of rotation rates

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.

Download Full-text

Strengthening mechanism of friction stir welded alpha titanium alloy specially designed T-joints

Journal of Manufacturing Processes ◽

10.1016/j.jmapro.2020.03.032 ◽

2020 ◽

Vol 55 ◽

pp. 1-12

Author(s):

Yu Su ◽

Wenya Li ◽

Xichang Liu ◽

Fuyang Gao ◽

Yan Yu ◽

...

Keyword(s):

Titanium Alloy ◽

Strengthening Mechanism ◽

T Joints ◽

Friction Stir ◽

Alpha Titanium

Download Full-text

Research on the Friction Stir Welding of Sc-Modified AA2519 Extrusion

Metals ◽

10.3390/met9101024 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1024 ◽

Cited By ~ 5

Author(s):

Robert Kosturek ◽

Lucjan Śnieżek ◽

Janusz Torzewski ◽

Marcin Wachowski

Keyword(s):

Mechanical Properties ◽

Friction Stir Welding ◽

Base Material ◽

Stir Zone ◽

Welding Parameters ◽

Friction Stir ◽

Treated Condition ◽

Heat Treated ◽

Heat Treated Condition ◽

Fsw Parameters

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.

Download Full-text