Investigations on influence of Particle size on workability And mos2 hybridization on Tribological behavior Of mg b4c composites

Abstract

This study investigates the influence of micro and nano B4C particles with different weight percentage of 0%, 5%and 10% in Mg-B4C composites fabricated by powder metallurgy technique on formability and eformation behaviour during cold upsetting under triaxial stress state condition. In addition, the hybridising effect of molybdenum disulphide (MoS2) reinforcement on tribological performance of magnesium hybrid composites has been studied. Powder morphology of Mg, B4C, MoS2 and their various composites have been characterised using X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) analysis. Cold upsetting of composites has been performed in the universal testing machine with an incremental loading of deformation in the order of 0.01MN until the first evident crack is initiated on the free surface. Dimensional changes, which include height, bulged diameter, top contact diameter, bottom contact diameter and density in the specimen, are accurately measured at the beginning and at the end of each loading interval. Measurement of densities is A load of 5 kg has been applied for 15 seconds at room temperature to determine the micro-hardness. The cold deformation behaviour of the aforementioned preforms has revealed that the actual effective stress is greater than the true axial, hoop, and mean/hydrostatic stress under triaxial stress conditions. It has been found that with the exception of the true axial stress, all the other stresses are found to be tensile in nature newline