P. Ravinder Reddy

SiC and Al 2 O 3 Reinforced Friction Stir Welded Joint of Aluminium Alloy 6061

This research presents the enhancement of mechanical properties of friction stir welded portion of aluminium alloy 6061 by incorporating additional reinforcing particulates of silicon carbide and aluminium oxide at weld interface. Friction stir welding (FSW) of AA6061, each plate of 200 mm × 100 mm × 4 mm thickness with silicon carbide and aluminium oxide as reinforcement at weld interface in four different volume proportions and without reinforcement are performed on vertical milling machine. In the present research, comparison has been done between mechanical properties of silicon carbide and aluminium oxide reinforced welded joints. Silicon carbide and aluminium oxide have been added as reinforcement by creating separate geometry, at the edges, where the welding is interfaced with four different volume proportions such as 10, 15, 25 and 30%. Tool steel of H13 grade is used as friction stir welding tool. The tool has outer shoulder diameter of 18 mm, pin diameter at the top of 7 mm and 5 mm at the bottom, and pin length of 3.7 mm. A rotational speed of 1120 rpm and transverse speed of 40 mm/min were selected. Quality assessment is carried out by visual inspection and non-destructive testing using fluorescent and radiography to reveal the surface and volumetric defects. Mechanical testings including tensile test, impact test, bend test and hardness test were conducted to study the behaviour of reinforced and unreinforced friction stir welded joints. Metallurgical evaluation has been performed by capturing the microstructures of base materials and at different zones of nugget, heat-affected zone (HAZ) by optical microscope to reveal the grain size and grain refinement at different zones. The experimental results indicate that the reinforcing particulates and percentage of reinforcing particulates have a major influence on the mechanical properties of friction stir welded joint. From microstructures, it has been shown that the addition of SiC and Al2O particles decreased the grain size and increased the strength of the joints.

Mechanical Behavior of Silicon Carbide Reinforced Friction Stir Welded Joint of Aluminium Alloy 6061

In this work the Mechanical behavior of reinforced welded butt joints of AA6061 aluminium alloy fabricated by friction stir welding process has been investigated. 10%, 15%, 25%, 30% volume fractions of Silicon carbide (SiC) particulates of 400 mesh were added at weld interface. This work was focused to study the effect of Sic as reinforcing material along with different volume proportions on the mechanical properties of friction stir welded joint of AA6061.The experimental results indicated that the reinforcing material and percentage of reinforcing material has a major effect on the mechanical properties of welded joint. The results of reinforced friction stir welded joints were correlated with parent material and without reinforced friction stir welded joint. The best results have been obtained at 25% volume fraction of silicon carbide particulates at weld interface. But at the same time percentage of elongation decreases and the behavior of material changes from ductile to brittle.

Effect of viscosity on radial stress, drawing stress and drawing force in fluid assisted deep drawing process

In this paper the influence of viscosity of fluid on radial stress, drawing stress and drawing force of magnesium alloys are presented through fluid-assisted deep drawing process. In this process, hydraulic pressure is to be applied in radial direction on the periphery of the blank for successful formation of cup. The fluid is placed in the die cavity and punch chamber, which are connected through bypass path in the die. The punch movement in the fluid chamber produces pressure in the fluid. This pressurised fluid is directed through the bypass path and acts radially on the blank periphery which reduces tensile stresses acting on the wall of the semi drawn blank. Due to punch force applied on the blank, radial and hoop stresses are produced and also shear stresses are acted by fluid on blank surface. Thus, viscosity phenomenon is applied in this process for evaluation of stress parameters.