The purpose of this research is to investigate the effect of heat treatment parameters on the tool life and surface roughness of dual phase steel. Optimization of machining parameters (cutting speed, feed and depth of cut) is carried out for the machinability tests on medium carbon low alloy steel. Taguchi's method of design is used to carry out machinability tests. Analysis of variance (ANOVA) is carried out to determine the relative contribution of machining parameters on tool life and surface roughness. Microstructure analysis is carried out to ascertain the machining behavior of the steel. Results have shown that, depth of cut and cutting speed are the most significant factors contributing on the variation of the tool life and surface roughness. Optimized machining parameters are calculated in order to obtain higher tool life and lower surface roughness value.

Austempered ductile iron (ADI) is a revolutionary material that has the ability to replace some of the commonly used steel forgings. ADI is being used in wide range of products because of the availability of this material with relatively lesser cost and its higher strength to weight ratio. Manganese is an important alloying element added to ductile iron for improving the hardenability. However, the amount of manganese has to be carefully selected to avoid any adverse effect on the mechanical properties. In this study, impact energy and tensile properties are determined for the various austempering temperatures and manganese content. Statistical analysis is carried out to determine the relative contribution of each factors on the results. Higher impact energy is observed at the higher austempering temperature of 420°C. No adverse effect on impact energy is observed for the addition manganese up to 1 wt%. Response surface methodology is used to optimize the parameters for obtaining the superior combination of ultimate tensile strength and impact energy. Regression equations are fit to predict the impact energy and ductility of manganese alloyed ADI.

Abstract. Al7075 alloy is the most commonly used by the aerospace industry. Al7075 alloy is characterized by its improved properties such as higher toughness, specific strength and hardness. The current work focuses on the preparation and characterization of age hardened Al7075-Grey cast iron composites. Two stage stir casting technique is used for the preparation of the composite. Age hardening treatment is imparted to enhance the mechanical characteristics. The variation of hardness and tensile strength with respect to aging temperature and percentage of reinforcement is analyzed. The composites exhibit higher hardness and tensile strength as the reinforcement percentage is increased at an aging temperature of 100 0 C.

High performance lightweight structures made of metal matrix composites (MMCs) are in demand for application in variety of industries such as aircraft, spacecraft, automobile, marine, sports equipment, etc. However, uniform distribution of the reinforcement phase to improve the mechanical properties and quality of MMCs has been the challenge for the manufacturing industries. Hence, researchers are focusing on the development of traditional low-cost method of producing metal matrix composites. In the view of above facts, an attempt is made to study the processing and characterization of Si-Al alloy reinforced with zirconium dioxide particulate composites in this paper. Hence, this paper concentrates on experimentally identifying the effect of stir cast and spray forming processing techniques followed by hot pressing on micro hardness, compressive strength, and tensile strength using Taguchi’s design of experiments for aluminum silicon matrix alloy reinforced with zirconium dioxide particulates. From the extensive experimentation on aluminum and silicon reinforced with the ZrO2 powder particulates, it was observed that there was an improvement in selected mechanical properties as the percentage of ZrO2 increased with 13 wt.% of silicon under spray forming processing technique compared to stir cast composites. This may be due to uniform distribution homogenous dispersion, larger work hardening rate, and structure of dislocation tangles around the ZrO2 particulates that occurred during spray forming processing technique. Further, results obtained from the interaction plot, contour plot, main effects plot, and analysis of variance (ANOVA) proved to be successful for identifying the optimum processing parameters for Si-Al alloy reinforced with zirconium dioxide particulate composites. Further, this paper also discusses wear study using pin on disc wear testing apparatus on spray forming processed aluminum and silicon (13.0 wt.%) alloy reinforced with the ZrO2 powder particulates based on Taguchi’s design of experiments followed by second order model generation for wear using response surface methodology. Finally, electrode wear study of spray forming processed aluminum and silicon alloy reinforced with the ZrO2 powder particulates using electric discharge machining by varying peak current (A), pulse on time (μs), and pulse off time (μs) using brass, copper, and graphite as electrode material based on L27orthogonal array. The understanding gained from the design of experiments in this paper can be used to develop future guidelines for processing and characterization of Si-Al alloy reinforced with zirconium dioxide particulate composites.

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