Effect of hybrid reinforcement at stirred zone of dissimilar aluminium alloys during friction stir welding

2019 ◽  
Vol 116 (6) ◽  
pp. 631 ◽  
Author(s):  
R. Ashok kumar ◽  
G.R. Raghav ◽  
K.J. Nagarajan ◽  
Sathish Rengarajan ◽  
P. Suganthi ◽  
...  

The main objective of this work is to modify the mechanical as well as surface properties of weld nugget by the reinforcement of hybrid ceramic particles (alumina and silicon carbide). This is accomplished by combining friction stir welding (FSW) and friction stir processing (FSP) on dissimilar AA6101-T6 and AA1350 aluminium alloys. For this purpose, various levels of mixing proportions of Al2O3 & SiC particles are used with constant groove depth and width i.e. constant groove dimension. To evaluate the quality of joints, tensile, bending, micro-hardness, wear and microstructural studies are carried out. Among these, reinforcement of 100% alumina particles exhibits better mechanical and wear properties. On the other hand, reinforcement of 100% silicon carbide particles produces poor mechanical and wear properties. And also increment in percentage of reinforcement of alumina particles improves the mechanical and wear properties of weld nugget, when compared to increment in percentage of reinforcement of silicon carbide particles.

Author(s):  
Sanjeev Verma ◽  
Vinod Kumar

Aluminium and its alloys are lightweight, corrosion-resistant, affordable and high-strength material and find wide applications in shipbuilding, automotive, constructions, aerospace and other industrial sectors. In applications like aerospace, marine and automotive industries, there is a need to join components made of different aluminium alloys, viz. AA6061 and AA5083. In this study friction stir welding (FSW) is used to join dissimilar plates made of AA6061-T6 and AA5083-O. The effect of varying tool pin profile, tool rotation speed, tool feed rate and tilt angle of the tool has been investigated on the tensile strength and percentage elongation of the welded joints. Box-Behkan design, with four input parameters and three levels of each parameter has been employed to decide the set of experimental runs. The regression models have been developed to investigate the influence of welding variables on the tensile strength and elongation of the welded joint. It is revealed that with the increase in welding parameters like tool rpm, tool feed rate and tilt angle of the tool, both the mechanical properties increase, reach a maximum level, followed by a decrease with further increase in the value of parameters. Amongst different types of tool pin profiles used, the FSW tool having straight cylindrical (SC) pin profile is found to yield the maximum strength and elongation of the welded joint for different combinations of welding parameters. Multiple response optimization indicates that the maximum UTS (135.83 MPa) and TE (4.35%) are obtained for the welded joint fabricated using FSW tool having SC pin profile, tilted at 1.11° and operating at tool speed and feed rate of 1568 rpm and 39.53 mm/min., respectively.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1938
Author(s):  
Haifeng Yang ◽  
Hongyun Zhao ◽  
Xinxin Xu ◽  
Li Zhou ◽  
Huihui Zhao ◽  
...  

In this study, 2A14-T4 Al-alloy T-joints were prepared via stationary shoulder friction stir welding (SSFSW) technology where the stirring pin’s rotation speed was set as different values. In combination with the numerical simulation results, the macro-forming, microstructure, and mechanical properties of the joints under different welding conditions were analyzed. The results show that the thermal cycle curves in the SSFSW process are featured by a steep climb and slow decreasing variation trends. As the stirring pin’s rotation speed increased, the grooves on the weld surface became more obvious. The base and rib plates exhibit W- or N-shaped hardness distribution patterns. The hardness of the weld nugget zone (WNZ) was high but was lower than that of the base material. The second weld’s annealing effect contributed to the precipitation and coarsening of the precipitated phase in the first weld nugget zone (WNZ1). The hardness of the heat affect zone (HAZ) in the vicinity of the thermo-mechanically affected zone (TMAZ) dropped to the minimum. As the stirring pin's rotation speed increased, the tensile strengths of the base and rib plates first increased and then dropped. The base and rib plates exhibited ductile and brittle/ductile fracture patterns, respectively.


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