S.J. Vijay

Microstructure and mechanical properties characterization of AA6061/TiC aluminum matrix composites synthesized by in situ reaction of silicon carbide and potassium fluotitanate

Aluminum alloys AA6061 reinforced with various amounts (0, 2.5% and 5%, mass fraction) of TiC particles were synthesized by the in situ reaction of inorganic salt K2TiF6 and ceramic particle SiC with molten aluminum. The casting was carried out at an elevated temperature and held for a longer duration to decompose SiC to release carbon atoms. X-ray diffraction patterns of the prepared AMCs clearly revealed the formation of TiC particles without the occurrence of any other intermetallic compounds. The microstructure of the prepared AA6061/TiC AMCs was studied using field emission scanning electron microscope (FESEM) and electron backscatter diffraction (EBSD). The in situ formed TiC particles were characterized with homogeneous distribution, clear interface, good bonding and various shapes such as cubic, spherical and hexagonal. EBSD maps showed the grain refinement action of TiC particles on the produced composites. The formation of TiC particles boosted the microhardness and ultimate tensile strength (UTS) of the AMCs.

Influence of tool rotational speed on microstructure and sliding wear behavior of Cu/B4C surface composite synthesized by friction stir processing

An attempt was made to synthesize Cu/B4C surface composite using friction stir processing (FSP) and to analyze the influence of tool rotational speed on microstructure and sliding wear behavior of the composite. The tool rotational speed was varied from 800 to 1200 r/min in step of 200 r/min. The traverse speed, axial force, groove width and tool pin profile were kept constant. Optical microscopy and scanning electron microscopy were used to study the microstructure of the fabricated surface composites. The sliding wear behavior was evaluated using a pin-on-disc apparatus. The results indicate that the tool rotational speed significantly influences the area of the surface composite and the distribution of B4C particles. Higher rotational speed exhibits homogenous distribution of B4C particles, while lower rotational speed causes poor distribution of B4C particles in the surface composite. The effects of tool rotational speed on the grain size, microhardness, wear rate, worn surface and wear debris were reported.

Microstructure and Mechanical Characterization of Aluminum Seamless Tubes Produced by Friction Stir Back Extrusion

AbstractFriction stir back extrusion (FSBE) is emerging as a novel method to produce high strength fine grained metallic tubes. The objective of the present work is to produce aluminum seamless tubes from solid cylindrical bars using FSBE and to report the microstructure and mechanical characterization. A die, tool and fixture were designed to carry out FSBE. A conventional friction stir welding machine was utilized for FSBE. A cylindrical bar of aluminum alloy AA6061-T6 was kept inside the hole in the die and extruded by plunging the rotating tool. The microstructure of the produced tube was studied using optical microscopy. The microstructure was found to be homogeneous along the tube. The microhardness and compressive strength of the tube have been presented in this paper. The results indicated that the FSBE process was capable of producing sound aluminum seamless tubes.n

Effect of Tool Rotational Speed on Microstructure and Microhardness of AA6082/TiC Surface Composites using Friction Stir Processing

Friction stir processing (FSP) is as a novel modifying technique to synthesize surface composites. An attempt has been made to synthesis AA6082/TiC surface composite using FSP and to analyze the effect of tool rotational speed on microstructure and microhardness of the same. The tool rotational speed was varied from 800 rpm to 1600 rpm in steps of 400 rpm. The traverse speed, axial force, groove width and tool pin profile were kept constant. Scanning electron microscopy was employed to study the microstructure of the fabricated surface composites. The results indicated that the tool rotational speed significantly influenced the area of the surface composite and distribution of TiC particles. Higher rotational speed provided homogenous distribution of TiC particles while lower rotational speed caused poor distribution of TiC particles in the surface composite. The effect of the tool rotational speed on microhardness is also reported in this paper.

A Review on Developing Surface Composites Using Friction Surfacing

Friction surfacing is an localized surface modification process of depositing consumable materials over substrate. FS, utilizes FSW technology allows joining of materials while avoiding the brittle intermetallic formations, involving temperatures below melting point and producing fine grained structure, results in exhibiting bond integrity and enhanced surface properties, reducing the costs associated with energy consumption and consumables. The process is used for corrosion and wear resistant coatings and for reclamation of worn engineering components and for coating components using dissimilar materials. This review presents the essentials of FS, parameters used, performance features of this technique. This describes the influence of the process parameters on surface properties of the surface composites produced and evaluated of the different materials. The FS is compared with other coating processes, and some of the applications are emphasized. The paper also discusses on few trails of FS made by the authors and the results of which is presented.