S S Sharma

FRP-Nanoclay Hybrid Composites: A Review

The review is on aimed an insight source for FRP-Nanoclay hybrid composite (nanocomposite) research, which includes basic structure/property, preparation & characterization techniques, mechanical properties and applications of hybrid composites. Key factors are discussed, which are influencing the mechanical properties of nanocomposite with nanoclay addition. Conclusions are also drawn based on the research of nanocomposites and improvement in mechanical properties.

Investigation on Effect of Nano-Fillers on Mechanical Properties of Epoxy Based Composites Using ANOVA

The present work aims to fabricate and characterize epoxy based composites with varying wt. % of nanoparticles as filler and to investigate and analyze the effects of nanoclay and nanocarbon with different wt. % on the epoxy resin. Different types of composites are prepared using 0, 2, 4 and 6 wt. % of fillers with rest of epoxy resin. Fillers are mixed with the resin by high speed mechanical stirrer for 2 hours. The mixture is transferred to the mould and allowed to cure. The specimens are prepared based on ASTM standard. The specimens are tested for tensile and flexural strength. Adding fillers resulted in change in the basic properties. ANOVA is applied to find the significance effect of 4 different weight percentage of fillers and different variety of fillers on the properties of composites.

Spheroidize Annealing and Mechanical Property Evaluation of AISI 1040 Steel

The importance of medium carbon steels as engineering materials is reflected by the fact that out of the vast majority of engineering grade ferrous alloys available and used in the market today, a large proportion of them are from the family of medium carbon steels. Typically medium carbon steels have a carbon range of 0.25 to 0.65% by weight, and a manganese content ranging from 0.060 to 1.65% by weight. Medium carbon steels are more resistive to cutting, welding and forming as compared to low carbon steels. From the last two decades a number of research scholars reported the use of veritiy of heat treatments to tailor the properties of medium carbon steels. Spheroidising is the novel industrial heat treatment employed to improve formability and machinability of medium/high carbon low alloy steels. This exclusive study covers procedure, the effects and possible outcomes of various heat treatments on medium carbon steels. The austenite phase present in steel above the critical temperature has the tendency to form variety of non equilibrium phases depending upon the degree of supercooling or cooling rates. The near spherical or curved shaped carbides records least resistance for machining because the blunt cornered shapes are having least free energy with minimum internal stresses. There is a need to formulate the heat treatment process to tailor the characteristics in line with the application. The age old normalizing treatment provides more nucleation sites required for so that finer spheroids are dispersed in the matrix to improve toughness with balanced bulk hardness related properties to improve machinability. In line with requirements, the heat treatment cycle to balance mechanical and microstructural properties of AISI 1040 structural steel is designed. It is observed that lower spheroidizing temperature gives finer spheroids, more in number with better improvement in toughness whereas higher Spheroidization temperature reduces hardness values with lesser spheroid density, accordingly reduces strength and impact resistance. The balanced improvement in properties may be incorporated for metal removal operations to improve productivity and tool life.

Process Optimization on Hardness of Precipitation Hardened Al6061 Alloy using Design of Experiments

Aluminium is ranked after iron and steel in the metal market. Aluminium 6061 alloy has been selected by many designers and engineers for different kind of applications. Further, its strength can be improved by cold working, refinement of grains, precipitation and dispersion hardening. In this work, trials are conducted for the investigation of the effects due to age hardening parameters like, solutionizing time, temperature and time for aging on hardness of 6061 Aluminium alloy using Design of Experiments. The response is predicted by using linier regression model. From the results it can be perceived that, the ageing temperature and aging time have a substantial effect on the response whereas, solutionizing time does not have a significant effect. For a specific set of parameters the hardness is improved from 50 to 74 BHN, resulted in an increase in hardness by about 50%.

Ferrite-martensite dual phase treatment of AISI 1040 steel and mechanical characterization

The present work is focused on the characteristics of dual phase (Ferrite-Martensite) medium carbon steel (AISI1040) austenized at different inter critical temperatures (750,770, and 790°C). AISI1040 is plain carbon steel with moderate strength and hardness. The machinability of the steel depends upon the balanced properties obtained by preferential control of phases (wt. % and type) by altering the room temperature structure. In this view, the dual phase is obtained by varying wt. % of ferrite and martensite structure in the steel and then subjected to bulk mechanical property (tensile, hardness, impact resistance and microstructure) analysis. As bought steel is subjected to normalizing treatment which is taken as datum for analysis. The dual phase structure obtained is then tempered to enhance the balanced properties. It was observed that hardness and tensile strength increases with low temperature tempering (260°C) compared to high temperature tempering (425°C) and impact resistance is excellent in high tempering temperature.

Influence of Spheroidizing Heat Treatment on Mechanical Properties of EN47 Steel

The high temperature phase austenite in steel has the property to transform into a variety of room temperature phases like coarse pearlite, bainite & martensite depending upon the cooling cycle. The machinability and toughness depend upon the shape and distribution of pro eutectoid harder phases. The spherical or oval shapes give lesser resistance for machining process. So it is required to design the heat treatment to tailor the property as required by the application. In this view, it is proposed to study the mechanical and micro structural properties of EN47 steel undergoing Spheroidization. The aim of this work is to test the hardness, toughness and wear property of the steel in spheroidised condition. Hardening treatment improves hardness of the material, a marginal decrease in hardness value with improved ductility is observed in tempering. Hardening and longer duration tempering show better wear resistance compared to other heat treatments. Both mild and severe wear regions are observed. Generally mild wear region is observed above five hours of continuous running of the specimen. Micro structural analysis shows the existence of pearlitic structure in as bought & normalized specimen, lath martensitic structure in hardened specimen.

Metallography & Bulk Hardness of Artificially Aged Al6061-B4C-SiC Stir Cast Hybrid Composites

Present investigation focusses on combined effect of B4C and SiC on the improvement in hardness with an average size of 35-40μm on Al6061 hybrid composite. Composites are produced by stir casting process. The effect of artificial aging treatment with different aging temperatures of 100, 150 and 200OC on the improvement in hardness is also investigated. Optical micrographs and Brinell hardness number have been discussed. An attempt is made to find out the intermetallic phase responsible for strengthening by Transmission Electron Microscopy. Due to positive response to age hardening treatment there is an improvement in the mechanical properties of Al6061 alloy & its hybrid composite. The aging kinetics is more accelerated in case of hybrid composites as compared to unreinforced Al6061 alloy because of presence of reinforcement particulate, which act as nucleation site for precipitation. Artificially aged at 100OC shows improvement in hardness by 120-220% due to the precipitation of secondary solute rich phase of alloying elements as compared Al6061 alloy.

Effect of Artificial Aging on Fracture Behavior of Al6061-Silica (SiO2) Composites

In the present work improvement in mechanical properties due to the presence of silicon oxide (SiO2) reinforced particles with an average size of 50μm and various weight percentage of (3, 6 and 9) on the hardness and fracture behaviour of Al6061-SiO2 composite is investigated. The influence of artificial aging with different aging temperatures on the mechanical properties was also assessed. Macro hardness and mechanism of fracture behaviour during tensile test have been discussed. Failure mode of fracture surface is studied to determine the parameters which influence the crack growth characteristics. Addition of SiO2 particles and artificially aging at 100°C for Al6061-SiO2 composite shows improvement in hardness by 140% and tensile strength by 60% due to the precipitation of finer secondary intermetallic phases of alloying elements. Fracture surface analysis for composite shows particle interface fracture and void nucleation growth failure.

Characteristic study for low melting point MMC using stir casting technique

This paper presents manufacturing of metallic composites using stir-casting method. The setup details and manufacturing methodology are explained. Microstructure and characterization of graphite-tin composite is also included. The tensile strength and hardness improvement is observed in tin-graphite MMC with increase in weight percentage of graphite. Metal-matrix composites (MMCs) are now attracting enormous interest. One of the prime reasons for this is that significant advances have been made in recent years on the development of fabrication routes, which are economically attractive and generate material of high micro structural quality. In particular, it is possible to produce composites, which are relatively free from gross defects (Clyne and Mason, 1987; Smith and Froes, 1984; Rodes and Spuurling, 1985; Hunt, 1989; Ted Guo and Tsao, 2000). However, it depends on the ability of synthesizing them with a consistent reproducibility in microstructure and properties. With continual development in fabricat...