B. K. Prasad

Bio: B. K. Prasad is an academic researcher from Advanced Materials and Processes Research Institute. The author has contributed to research in topics: Lubricant & Deformation (engineering). The author has an hindex of 5, co-authored 6 publications receiving 132 citations.

Cast in situ Cu–TiC composites: Synthesis by SHS route and characterization

Abstract: The present investigation discusses observations pertaining to the synthesis of Cu-based composites containing TiC particles in the range of 45–50 volume % by self-propagating high temperature synthesis (SHS) process. A composite with 11–13 volume % TiC dispersion was also synthesized through remelting and dilution. The composites were observed to contain a copper matrix together with a Cu–Ti intermetallic compound, TiC dispersoid particles and partially reacted graphite. The regions showing partially reacted graphite (carbon) became less prominent in the diluted composites. Al addition led to the refinement of TiC particles, higher hardness, reduced density and improved degree of formation and better homogeneity of the distribution of TiC particles. Dilution caused reduced hardness, while the density followed a reverse trend.

Compressive deformation behaviour of Al alloy (2014)–10 wt.% SiCp composite: Effects of strain rates and temperatures

Abstract: This paper deals with the compressive deformation behaviour of AA2014–10 wt% SiCp composites synthesized by stir casting technique The response of the composites was studied over the strain rates of 001–10/s and the temperature range of 200–500 °C The flow stress increased with increasing strain rates while increasing temperature produced a reserve effect The flow behaviour of the samples has been represented by Zener–Holloman parameter Z that was affected by strain rate and temperature in a manner similar to that of the flow stress The lowering of Z value with increasing temperature is essentially due to extensive dynamic softening The stress exponent ( n ) and deformation activation energy ( Q ) have been evaluated by linear regression analysis The activation energy for the hot deformation of the composite was found to be 168 kJ/mol, which is higher than bulk self diffusion of pure Al ie, 142 kJ/mol The higher activation energy required for the flow of composite was mainly due to the alloying elements present in the Al matrix and dispersion of SiC particles that restricted the flow of material

Effects of Some Solid Lubricants Suspended in Oil Toward Controlling the Wear Performance of a Cast Iron

Abstract: The present investigation deals with the examination of the sliding wear response of a gray cast iron in oil lubricated condition over a range of applied pressure. The composition of the oil lubricant was changed by adding 5.26 wt % solid lubricant particles. The solid lubricants used were graphite, talc, MoS 2 , and lead. The observed wear response of the samples has been substantiated through the characteristics of wear surfaces, subsurface regions, and debris particles and discussed in terms of specific response of different microconstituents, such as ferrite, pearlite, and graphite present therein. Operating wear mechanisms were assessed through the observed features of wear surfaces, subsurface regions, and debris. The wear rate increased with applied pressure. The slope of the wear rate versus pressure plots was low up to a critical pressure. This was followed by a sudden rise in the slope at higher pressures irrespective of the test environment. The frictional heating was affected by pressure in a manner practically identical to that of the wear rate. The presence of graphite, MoS 2 , and lead in the oil led to a substantial decrease in the wear rate and severity of frictional heating. The oil plus lead lubricant mixture was observed to offer best results in terms of reduced wear rate and lower frictional heating. This was followed by the ones containing graphite and MoS 2 while talc caused the wear performance of the samples to deteriorate over that of the bare oil. However, the severity of frictional heating decreased in general in the oil containing solid lubricant particles. Seizure brought about high frictional heating and wear rate.

Hot Deformation Behaviour of AA2014–10 wt% SiC Composite

Abstract: The hot compression behaviour of AA2014 alloy having 10 wt% SiC particles was studied over a wide range of temperatures (ambient to 400 °C) and strain rates (0.01–10/s). The results were compared with those obtained from identical tests performed on the base alloy to understand the effect of the SiC particle reinforcement. Processing maps were generated using dynamic materials model from the flow stress of the samples. Microstructures of the deformed samples suggest the occurrence of dynamic recrystallization at high temperatures and low strain rate. Flow localization and adiabatic shear bands were observed at higher strain rates and temperatures. The lack of cohesion between SiC particles and the matrix was found to be responsible for the deteriorating deformation behavior of the composite over most of the processing domains. The activation energy for high temperature deformation in the presence of the SiC particles in the alloy was found to be significantly higher than that of the matrix. This makes deformation processing of the composite more difficult than that of the matrix.

A tribological study of vegetable oil enhanced by nano-platelets and implication in MQL machining

Abstract: Minimum Quantity Lubrication (MQL)-based machining process has many merits over not only conventional flood cooling machining but also dry machining. These merits include cost reduction, industrial hygiene, reduction of air-bourn particles etc.. However, few disadvantages make the MQL-based machining process impractical to be adopted in many industrial production settings. More specifically, the cutting speed in a typical MQL process is restricted because the MQL process does not allow efficient cooling of cutting tools. The amount of oil used in MQL processes is barely enough for less aggressive machining conditions and does not effectively cool the cutting tool essential in more aggressive cutting conditions. At high cutting speeds, the oil will simply evaporate or disintegrate as soon as the oil droplets strike the tools already heated to high cutting temperatures. In this paper, new nano-platelet-enhanced MQL oils are developed to mitigate this major deficiency of MQL process. In particular, exfoliated Graphite nano-platelet (xGnP) and XGS Hexagonal Boron Nitride (hBN) produced by XG Science, Inc. (Lansing, Michigan) were mixed into a typical vegetable oil used in MQL process. The process enhancement by these nano-platelets is possible because these nano-platelets in a multiple-layer scheme can readily slide to provide additional lubricity. When the mixture of oil and nano-platelets are applied, the nanoplatelets provide additional lubricity even after the oil droplets have been disintegrated during high speed machining. Thus, the enhancement achieved by adding nano-platelets allows us to expand the processing envelope of MQL. In this paper, not only the comparison between xGnP and XGS hBN but also multiple combinations of nano-platelet-enhanced MQL oils with varying contents have been studied with a ball-on-disc set-up in a reciprocating motion in order to study the friction and wear characteristics of these lubricants. More importantly, MQL-based ball-milling experiment has been conducted with these mixtures, which show very promising results for future MQL research.

Manufacture of Nano-Sized Particle-Reinforced Metal Matrix Composites: A Review

Abstract: Compared to the micro-sized particle-reinforced metal matrix composites, the nano-sized particle-reinforced metal matrix composites possess superior strength, ductility, and wear resistance, and they also exhibit good elevated temperature properties. Therefore, the nano-sized particle-reinforced metal matrix composites are the new potential material which could be applied in many industry fields. At present, the nano-sized particle-reinforced metal matrix composites could be manufactured by many methods. Different kinds of metals, predominantly Al, Mg, and Cu, have been employed for the production of composites reinforced by nano-sized ceramic particles such as carbides, nitrides, and oxides. The main drawbacks of these synthesis methods are the agglomeration of the nano-sized particles and the poor interface between the particles and the metal matrix. This work is aimed at reviewing the ex situ and in situ manufacturing techniques. Moreover, the distinction between the two methods is discussed in some detail. It was agreed that the in situ manufacturing technique is a promising method to fabricate the nano-sized particle-reinforced metal matrix composites.