Effect of rotational speeds on microstructure and mechanical properties of friction stir-welded 7075-T6 aluminium alloy

2011 ◽  
Vol 225 (8) ◽  
pp. 1761-1773 ◽  
Author(s):  
H Rezaei ◽  
M H Mirbeik ◽  
H Bisadi
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Rotational Speed ◽  
Thermal Cycle ◽  
Al Alloys ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Weld Properties ◽  
Rotary Speed

In this article, effects of rotational speed on the microstructure and mechanical properties of friction stir-welded 7075-T6 Al alloys were investigated. Good correlation existed between the rotational speeds and weld properties. It was found that with increase in the rotational speed, higher pick temperatures and wider thickness of the heat-affected zone were obtained, and then grain coarsening, dissolution, and accumulation of hardening precipitates in grain boundaries. The average grain size of nugget increased from 6.8 to 8.9 µm, with increasing rotary speed from 600 to 1550 r/min. In addition, the best mechanical properties were obtained at moderate rotational speed of 825 r/min while ultimate tensile strength and elongation were 405 MPa and 6.1 per cent, respectively. Also, it was observed that at low welding speed of 60 mm/min, the weld properties are found to be dominated by the thermal cycle rather than the plastic deformation induced by tool, so as to make a reduction in hardness and strength of the weld when using higher rotational speeds.

Microstructure and Mechanical Properties of a Friction Stir Processed Al-Zn-Mg-Cu Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 1428-1431 ◽  
Author(s):  
Margarita Vargas ◽  
Sri Lathabai
Keyword(s):  
Mechanical Properties ◽  
Rotational Speed ◽  
High Strength ◽  
Travel Speed ◽  
Nugget Zone ◽  
Friction Stir ◽  
Complex Interactions ◽  
Cu Alloy ◽  
Microstructure And Mechanical Properties ◽  
Aa 7075

Friction stir processing (FSP) was performed on AA 7075-T6, a heat treatable high strength Al-Zn-Mg-Cu alloy. The two main FSP parameters, the tool rotational and travel speed, were varied systematically in order to understand their influence on the microstructure and mechanical properties of the processed zone. At a given rotational speed, increasing the travel speed increased the microhardness of the nugget (stir) zone; for a given travel speed there appeared to be an optimum rotational speed which resulted in the highest microhardness. The range of FSP parameters used did not significantly influence the nugget zone grain size. It is suggested that the observed mechanical properties are a result of the complex interactions between the FSP thermo-mechanical effects and the processes of dissolution, coarsening and re-precipitation of the strengthening precipitates in this alloy.

scholarly journals Microstructure and Mechanical Properties of Friction Stir Welded Joints Between Commercially Pure Copper and Al 6351 Alloy

2017 ◽  
Vol 62 (3) ◽  
pp. 1819-1825
Author(s):  
V.C. Sinha ◽  
S. Kundu ◽  
S. Chatterjee
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Rotational Speed ◽  
Pure Copper ◽  
Stir Zone ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
Commercially Pure ◽  
Microstructure And Mechanical Properties ◽  
Commercially Pure Copper

AbstractIn the present study, the effect of tool rotational speed on microstructure and mechanical properties of friction stir welded joints between commercially pure copper and 6351 Al alloy was carried out in the range of tool rotational speeds of 300-900 rpm in steps of 150 rpm at 30 mm/minutes travel speed. Up to 450 rpm, the interface of the joints is free from intermetallics and Al4Cu9intermetallic has been observed at the stir zone. However, Al4Cu9intermetallic was observed both at the interface and the stir zone at 600 rpm. At 750 and 900 rpm tool rotational speed, the layers of AlCu, Al2Cu3and Al4Cu9intermetallics were observed at the interface and only Al4Cu9intermetallics has been observed in the stir zone. The maximum ultimate tensile strength of ~207 MPa and yield strength of ~168 MPa along with ~6.2% elongation at fracture of the joint have been obtained when processed at 450 rpm tool rotational speed.

Effect of Enhanced Cooling on the Microstructure and Mechanical Properties of Friction Stir Spot-Welded AZ31 Magnesium Alloy

2016 ◽  
Vol 850 ◽  
pp. 784-789
Author(s):  
Song Lin Chen ◽  
Da Tong Zhang
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Cooling Water ◽  
Stir Zone ◽  
Az31 Magnesium Alloy ◽  
Air Cooling ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Spot Welded

AZ31 magnesium alloy was friction stir spot welded in air and cooling in water. The effect of the enhanced cooling rate on the microstructure and mechanical properties of the joint was analyzed. The results showed that flowing water had obvious cooling effect instantaneously, which significantly restrained the growth of dynamic recrystallized grains. The average grain size in stir zone was 1.3μm in cooling water condition, which is far smaller than that of the joint prepared in air cooling condition. Under the condition of enhanced cooling, the microhardness in stir zone significantly increased, the ultimate tensile load (~ 3.99kN) increased by 15.7%, and the tensile deformation value (~ 3.65 mm) increased by 62.2%. Dimples in SEM fracture morphologies indicated the better plastic deformation capacity of joints prepared by cooling water, which failed through a mixture mode of ductile and brittle fracture.

Investigation of Microstructure and Mechanical Properties of Friction Stir Lap Jointed Ni Base Superalloy

2012 ◽  
Vol 724 ◽  
pp. 481-485
Author(s):  
Kuk Hyun Song ◽  
Kazuhiro Nakata
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Friction Stir Welding ◽  
Base Material ◽  
Lap Joints ◽  
Stir Zone ◽  
Inconel 600 ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

This study evaluated the microstructure and mechanical properties of friction stir welded lap joints. Inconel 600 and SS 400 as experimental materials were selected, and friction stir welding was carried out at tool rotation speed of 200 rpm and welding speed of 100 mm/min. Applying the friction stir welding was notably effective to reduce the grain size of the stir zone, as a result, the average grain size of Inconel 600 was reduced from 20 μm in the base material to 8.5 μm in the stir zone. Joint interface between Inconel 600 and SS 400 showed a sound weld without voids and cracks. Also, the hook, along the Inconel 600 alloy from SS 400, was formed at advancing side, which directly affected an increase in peel strength. In this study, we systematically discussed the evolution on microstructure and mechanical properties of friction stir lap jointed Inconel 600 and SS 400.

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