Enforcement of stricter environmental policies demands alternative methods that could reduce the usage of cutting fluid during machining. Thus, dry machining and minimum quantity lubrication (MQL) machining are gaining practical importance. Due to enhanced mechanical and thermal properties, aluminium based nanocomposites have wide application in aerospace and automobile industries. In this work, asqueeze cast hybrid nanocomposite is developed with the reinforcement of 0.5 wt% hexagonal boron nitride and 1 wt% alumina particles in the base matrix of Al 7075 that is subjected to a squeezing pressure of 150 MPa. During the turning of this hybrid nanocomposite, thefeed rate is varied (0.1, 0.2, and 0.3 mm/rev)and its influence on the generated forces, tool wear and surface roughness under dry and MQL environments is performed. The results are compared with squeeze cast unreinforced aluminium alloy and presented. © 2017 Taylor & Francis.

Kannan C

Department of Automotive Engineering

School of Mechanical Engineering

Vellore Campus

Ramanujam R

Department of Manufacturing Engineering

Balan A.S.S.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Machinability studies on Al 7075/BN/Al2O3 squeeze cast hybrid nanocomposite under different machining environments

Materials and Manufacturing Processes

Aluminium metal matrix replaces high melting point and high density conventional materials, thus minimizing the usage of energy and supporting the environment. This work develops a low-weight, high-strength composite material with the help of AA 6061 and ZrO2 through a stir casting route incorporated with a squeeze casting setup. Machining and machining tools create impacts on clean environments, as they deal with lubricants and power consumption. Having taken this issue into consideration, this research studies the effect of machining parameters on surface roughness, tool wear, and cutting force, while turning the developed metal matrix composite in dry and minimum quantity lubrication conditions. The turning experiment was performed by designing parameters using an L27 orthogonal array. The turning condition was dry and with minimum quantity lubrication (MQL). The responses obtained in the turning process were analysed using the analysis of variance (ANOVA) technique to find the most influential factor and its percentage contribution. Optimal machining parameters were investigated and tabulated with the help of main effect plots and S/N ratio graphs. Studies prove that there is a linear relationship between MQL versus surface roughness and tool wear, and there was no substantial effect on cutting force. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

Fulltext

Metals

Machinability Study of Developed Composite AA6061-ZrO2 and Analysis of Influence of MQL

The aim of this research work is to evaluate the mechanical and tribological behaviour of Al 7075 based self-lubricated hybrid nanocomposite under different treated conditions viz. as-cast, T6 and deep cryo treated. In order to overcome the drawbacks associated with conventional stir casting, a combinational approach that consists of molten salt processing, ultrasonic assistance and optimized mechanical stirring is adopted in this study to fabricate the nanocomposite. The mechanical characterisation tests carried out on this nanocomposite reveals an improvement of about 39% in hardness and 22% in ultimate tensile strength possible under T6 condition. Under specific conditions, the wear rate can be reduced to the extent of about 63% through the usage of self-lubricated hybrid nanocomposite under T6 condition. © 2018 IOP Publishing Ltd.

Materials Research Express

Mechanical and tribological behaviour of molten salt processed self-lubricated aluminium composite under different treatments

The application of emulsion for combined heat extraction and lubrication requires continuous monitoring of the quality of emulsion to sustain a desired grinding environment; this is applicable to other grinding fluids as well. To sustain a controlled grinding environment, it is necessary to adopt an effectively lubricated wheel–work interface. The present work aims to develop a numerical model to replicate the mist formation in minimum quantity lubrication (MQL) grinding using a fluent-based computational fluid dynamics (CFD) flow solver. The MQL parameters considered for this study are air pressure and the mass flow rate. Simulation of the atomization under turbulent conditions was done in a discrete phase model (DPM) owing to the fact that oil mass flow rates are very low and oil acts as a discrete medium in air. Jet velocity and droplet diameters were also obtained under different input conditions to find the optimum value of air pressure and mass flow rate of oil to achieve the desired results (lower cutting force and surface roughness) in MQL grinding of superalloy (Inconel 751). It is seen that medium size (around 16.3 µm) of droplet plays a significant role in improved performance by the way of reduction in cutting force and surface roughness. © 2017 Taylor & Francis Group, LLC.

Machining Science and Technology

Computational fluid dynamics analysis of MQL spray parameters and its influence on superalloy grinding

In this research work, a comparative evaluation on the mechanical and microstructural characteristics of aluminium based single and hybrid reinforced nanocomposites was carried out. The manufacture of a single reinforced nanocomposite was conducted with the distribution of 2 wt.% nano alumina particles (avg. particle size 30–50 nm) in the molten aluminium alloy of grade AA 7075; while the hybrid reinforced nanocomposites were produced with of 4 wt.% silicon carbide (avg. particle size 5–10 µm) and 2 wt.%, 4 wt.% nano alumina particles. Three numbers of single reinforced nanocomposites were manufactured through stir casting with reinforcements preheated to different temperatures viz. 400 °C, 500 °C, and 600 °C. The stir cast procedure was extended to fabricate two hybrid reinforced nanocomposites with reinforcements preheated to 500 °C prior to their inclusion. A single reinforced nanocomposite was also developed by squeeze casting with a pressure of 101 MPa. Mechanical and physical properties such as density, hardness, ultimate tensile strength, and impact strength were evaluated on all the developed composites. The microstructural observation was carried out using optical and scanning electron microscopy. On comparison with base alloy, an improvement of 63.7% and 81.1% in brinell hardness was observed for single and hybrid reinforced nanocomposites respectively. About 16% higher ultimate tensile strength was noticed with the squeeze cast single reinforced nanocomposite over the stir cast. © 2017

Journal of Advanced Research

Comparative study on the mechanical and microstructural characterisation of AA 7075 nano and hybrid nanocomposites produced by stir and squeeze casting

Journal	Materials and Manufacturing Processes
Publisher	Informa UK Limited
ISSN	1042-6914
Open Access	No