Browsing by Author "Ravikumar, K.S."

Now showing 1 - 3 of 3

Effect of Ball Milling on the Tensile Properties of Aluminum-Based Metal Matrix Nanocomposite Developed by Stir Casting Technique
(SAE International, 2021) Ravikumar, K.S.; Ghanaraja, S.; Ramesh, M.R.
Combining ball milling with stir casting in the synthesis of nanocomposites is found effective in increasing the strength and ductility of the nanocomposites. In the first step, the nanoparticles used as reinforcement are generated by milling a mixture of aluminum (Al) and manganese dioxide (MnO2) powders. A mixture of Al and MnO2 powders are mixed in the ratio of 1:2.4 by weight and milled at 300 rpm in a high-energy planetary ball mill for different durations of 120 min, 240 min, and 360 min to generate nano-sized alumina (Al2O3) particles. It is supposed that the powders have two different roles during milling, firstly, to generate nano-sized Al2O3 by oxidation at the high-energy impact points due to collision between Al and MnO2 particles, and secondly, to keep nano-sized Al2O3 particles physically separate by the presence of coarser particles. In the second step, 0.5 weight percent (wt%), 1 wt%, 1.5 wt%, and 2 wt% of the generated Al2O3 nanoparticles are reinforced in molten aluminum-magnesium (Al-Mg) alloy matrix via stir casting to synthesize nanocomposites. The effect of milling on the microstructure of the powder mixture before and after milling has been studied with the use of a scanning electron microscope (SEM) and X-ray diffraction analysis (XRD). The microstructure of the cast composites is examined under SEM, and the fractured surface of the tensile specimens is analyzed through SEM fractographs. Ball milling of reinforcement before adding to the melt brings considerable improvement in the integration and uniform dispersion of the milled particle in the Al-Mg alloy matrix melt, which leads to improvement in the strength and ductility of the cast nanocomposites. ©
Effect of Milling on the Hardness and Wear Behaviour of Cast Al6061 Reinforced with Al2O3 Nanoparticles
(Springer Science and Business Media Deutschland GmbH, 2022) Ravikumar, K.S.; Ghanaraja, S.; Ramesh, M.R.
Alumina nanoparticles is generated through planetary ball milling of powder mix compraise of aluminium (Al) and manganese dioxide (MnO2). The powder mix of Al and MnO2 is considered in the weight proportion of 1:2.416 and milled for 120, 240 and 360 min. In the milling jar, the powder mix will experience impact force while collusion with ball-powder-ball and ball-powder-wall of the jar. These impact force will cause cyclic deformation and fracture of the powder mix, which results in the synthesis of nano alumina. The morphology of the powder mix prior to milling and post milling for different times has been studied by scanning electron microscope and X-ray diffraction. Cast composites have been synthesized via liquid metallurgy technique using Al6061 as matrix and generated alumina particles by milling is considered as reinforcement. Comparative study have been conducted between the composites prepared by considering Al6061 as matrix and as received powder as reinforcement with the composites prepared by considering Al6061 as matrix and alumina generated through the milling as reinforcement. The reinforcement added to the the matrix in the varying proportions of 0.5, 1 and 1.5 wt% of particles before milling and after milling. The effect particles size related to hardness and wear property of cast composites are studied. It was found that the wear resistance increased monotonically with hardness. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Synthesis and characterization of nano-alumina powder by milling of Al and MnO2powder mixture
(Elsevier Ltd, 2021) Ravikumar, K.S.; Ghanaraja, S.; Ramesh, M.R.
There are extensive study on nano composites because of its outstanding mechanical properties when compared with the monolithic materials. The manufacturing of nano particles presents an increasing interest. There are two basic strategy for the synthesis of nano particles, they are bottom up and top down approach. Nano particles are built atom by atom in the bottom up approach. In the synthesis of nano particles, top down approach is most applied one. In this approach, bulk materials are broken down gradually into smaller sizes until they reach nano size. Ball milling is most widely used method for the top down approch. Ball milling process involves milling of constituent powders in a vial where mechanical deformation and chemical reactions takes place between the powders to form new phase. In the present study, constituent powder mixture of Al (1.845 Î¼m) and MnO2(0.75 Î¼m) are subjected to high energy planetary ball milling to form new phase which is of nano alumina (Al2O3). Initially, Al and MnO2powder mixture are taken in the ratio of 1:2.416 by weight for different milling duration of 120 min, 240 min and 360 min. The constant speed of the mill was maintained at 300 rpm. The powder mixture inside the mill subjected to impact force between ball to ball and between ball to wall of the container undergo cyclic deformation, cold welding and fracture ensures the generation of nano alumina particles in the range of 50 nm to 560 nm. The effect of mechanical alloying on the microstructure of the powder mixture have been studied by scanning electron microscope (SEM), X-ray diffraction (XRD) and EDS. Toluene was used during milling appears effective process control agent to avoid severe agglomeration and to enhance milling effect. Â© 2021 Elsevier Ltd. All rights reserved.