NOPR Collection:

Experimental investigations on wire electrical discharge machining characteristics of aluminum hybrid compositesc

2018-08-01T00:00:00Z

Title: Experimental investigations on wire electrical discharge machining characteristics of aluminum hybrid compositesc Authors: Kumar, T T Satheesh; Subramanian, R; Velmurugan, C; Vinoth, K Somasundara Abstract: Wire electrical discharge machining (WEDM) is a very efficient process for machining composite specimens compared to other conventional machining process. In this work, WEDM process is used to investigate the machining characteristics of aluminum alloy reinforced with hard chromium carbide and soft graphite particles. Optimization of WEDM parameters is carried out to maximize of material removal rate (MRR) as well as to minimize surface roughness (SR) of the composites. Mathematical models were developed using response surface methodology (RSM) to predict the chosen response values. Scanning electron microscope (SEM) investigations showed a near uniform distribution of reinforcements within the matrix. It is found that during WEDM machining process, maximization of MRR of the composite occurred with an increase in pulse-on-time and spark gap voltages. Minimum surface roughness is observed with an increase in peak current and pulse- off time. Page(s): 281-290

A comparative study on mechanical properties of heat treated steel EN24 and its MMC with SiC

2018-08-01T00:00:00Z

Title: A comparative study on mechanical properties of heat treated steel EN24 and its MMC with SiC Authors: Dileep, B P; Sridhar, B R Abstract: The investigation has been undertaken to evaluate the mechanical properties of sintered and heat treated EN24 alloy steels by using elemental powders through powder metallurgical techniques. The green compacts obtained through powder metallurgy route have been sintered at 1150±10°C in vacuum furnace. Silicon carbide content used as reinforcement in EN24 matrix is varied and tensile specimens are prepared. Tensile test specimens prepared from EN24 steel plate is subjected to standard heat treatment. Both Sintered and heat treated EN24 steels are subjected to tensile tests with by 40 Tonn Capacity Hydraulic Universal Testing Machine. Their microstructures are evaluated using optical and electron microscopy. From the data obtained a comparison of the properties of the En 24 composite with heat treated En 24 steel has been attempted. Page(s): 291-294

Experimental study of tensile and flexural properties of kans grass fiber reinforced polyester composites

2018-08-01T00:00:00Z

Title: Experimental study of tensile and flexural properties of kans grass fiber reinforced polyester composites Authors: Ahlawat, Vishal; Parinam, Anuradha; Kajal, Sanjay Abstract: The present paper describes the use of kans grass fiber as a new natural fiber in composite development. The fibers are collected from riped kans grass plants and reinforced in to the polyester resin with 0, 10, 13.35, 18 and 20.08 vol%. The tensile strength, tensile modulus and the density of kans grass fiber are found to be 278-619 MPa, 8.1-11.1 GPa and 441 kg/m³, respectively. The composites tensile strength and modulus increase with increase in the fiber vol% from 10 to 20.08. The flexural strength also increases with increase in fiber vol% but remains lower than that of the neat polyester. It has been further observed that the addition of fibers increases the flexural modulus and made the 20.08 vol% specimen 2.1 times stiffer than the neat specimen. The fiber reinforcement has noticeable improvement in specific tensile strength, and modulus and specific flexural modulus of the composite specimens whereas no significant increment is observed in specific flexural strength. This experimental study shows the potential of kans grass fibers in the development of composites for light weight applications due to its low density and better strength. Page(s): 295-300

Analysis of temperature distribution in wire electrical discharge machine on hybrid Al-MMCs

2018-08-01T00:00:00Z

Title: Analysis of temperature distribution in wire electrical discharge machine on hybrid Al-MMCs Authors: Ramesh, S; Gokulakannan, G; Natarajan, N; Krishnaraj, V Abstract: Wire electrical discharge machine (WEDM) is a non-traditional machining technique for producing parts with higher accuracy Al6061 reinforced with 7% silicon carbide and 3% boron carbide is selected as a work-piece and molybdenum wire as an electrode in this work. The machining in WEDM may result in work-piece surface damage and this is due to the materials thermal properties. The work-piece surface consists of voids, cracks and residual thermal stress after machining due to the spark which is used in machining process. The materials which are machined in WEDM are used in aerospace applications. Particle reinforced aluminium metal matrix composites (Al-MMCs) are used as Fan Exit Guide vane in aerospace gas turbine engine and they are operating at very high temperature. The catastrophic failure may happen due to the availability of thermal damage layer. In this work, the WEDM is modelled based on the finite element method program by using the machining parameters such as voltage, current and pulse on time. In order to reduce the thermal damage layer, the set of parameter which is having the least temperature distribution on the material is analysed. It is determined that, the least temperature distribution over the material results in the least thermal damage layer thickness. Page(s): 301-306