NOPR Collection:

Friction stir processing of aluminum alloys

2021-02-01T00:00:00Z

Title: Friction stir processing of aluminum alloys Authors: Singh, Pratap; Kandikonda, Hans Raj Abstract: In most of the industries like automobile, aircraft, shipbuilding, etc., surface composites play an important role as they enhance strength, hardness, and microstructure. Friction Stir Processing is a solid-state surface alteration and surface engineering technique employed for development of Metal Matrix Composite surfaces. It enables alteration of the surface, control of microstructure, enhancement of wear and improvement in mechanical properties. This process was first initiated with Al-based alloys for enhancing their mechanical properties and now extended to the fabrication of various other alloys also such as Mg, Ti, Cu, etc. An effort is made in this article to review the current trends and future scope of Al alloy composites using FSP including various FSP strategies applied to improve surface characteristics, hardness, microstructure, enhancement of wear. Page(s): 5-20

Development and certification of chromic acid-free anodizing process for aircraft grade aluminium alloys

2021-02-01T00:00:00Z

Title: Development and certification of chromic acid-free anodizing process for aircraft grade aluminium alloys Authors: Jayam, Balaraju N; Varathan, Ezhilselvi; Srivastava, Meenu; Thayee, Manikandanath N; Murugasen, Ganesh; Ramasamy, Shanmugavel; Kale, Shirish Sharad; Kasturi, Nagacharan V; Chikkamadal, Manjunatha M Abstract: Chromic acid (Cr⁶⁺) anodization process is widely used for the corrosion protection of aircraft aluminium alloys. Hexavalent chromium being toxic in nature need to be phased out by eco-friendly alternatives. In the present study modified tartaric-sulphuric acid (TSA) process has been developed followed by sealing in permanganate based bath to obtain 4 to 6 µm thick anodic oxide layer on 2024-T3, 6061-T6 and 7075-T6 aluminium alloys. The process was carried out using a pilot scale anodizing plant. The anodized specimens were characterized for visual observation, thickness, adhesion, electrical breakdown voltage, corrosion resistance and tensile behaviour. All the tests were carried out as per MIL-A-8625F specifications. The specimens were also subjected for about 800 hrs to real time corrosion testing, 200 metres away from sea shore at Mandapam Camp, Rameshwaram, India. The performance of the permanganate sealed TSA anodized aluminium alloys are comparable with that of the conventional chromic acid anodized coatings. This chromic acid-free anodization process has been qualified to airworthiness regulating standards by Indian military certification authorities. Efforts are in progress to commercialize this technology for use on aero platforms. Page(s): 21-27

Effect of foil thickness and cell size of honeycomb on energy absorption of aluminium honeycomb sandwich composite (Charpy Test)

2021-02-01T00:00:00Z

Title: Effect of foil thickness and cell size of honeycomb on energy absorption of aluminium honeycomb sandwich composite (Charpy Test) Authors: Rajput, Arun; Sunny, Mohammed Rabius; Sarkar, Arunjyoti Abstract: Sandwich composites are special class of materials because of peculiar properties such as lightweight, high energy absorbing capacity, and high damping, etc. These properties make them suitable for their use in aerospace and marine industry. Generally, metal or FRP sheets are used as skin/face sheet and honeycomb, foam and balsa wood, etc. are used as core materials. The elastic properties of the honeycomb are the function of foil thickness and cell size. In the present study, the effect of parameters (Foil thickness and Cell size) of the honeycomb on the energy absorption capacity of the sandwich composite was investigated through experimental and numerical studies. Experiments were carried out on four sandwich composites having a variable combination of foil thickness, and cell size by using the Charpy ASTM E-23 machine. Further, numerical analyses were carried out using finite element (FE) software Abaqus. The experimental and numerical results were found to be in good agreement. The results show that energy absorption to mass ratio increases with the increase in foil thickness and with the decrease in cell size. For the improvement of energy absorption to mass ratio, the effect of change in the foil thickness is significant compared to that of change in cell size. Failure mechanism was discussed through numerical study. The impact force resisted by the sandwich composites was presented by using the impulse-momentum equation. Page(s): 28-35

Use of electronic waste plastic in asphalt mix with marble dust as filler

2021-02-01T00:00:00Z

Title: Use of electronic waste plastic in asphalt mix with marble dust as filler Authors: Sinha, Rohan; Kumar, Saksham; Garg, Sarthak; Prasad, Narad Muni Abstract: E-waste is becoming burgeoning global issue, which showcases the impacts of the same on environment and on humans. Marble cutting industries is another industry producing huge amount of marble dust as a waste which is degrading the environment. E-waste and waste marble dust can be utilized in construction industry in different forms thus helps in reducing its impact on environment. In this analysis, electronic waste plastic materials including recycled PCB’s and other PVC components of e-waste has been used as a partial replacement for coarse aggregates and marble dust is used as complete replacement for filler in asphalt mix for pavement. A significant increase of Marshall Stability and Flow Value has been observed as percentage of e-waste plastic increases. The plastic content of mix varies 0 %, 4 %, 8 % and 12 % by weight of aggregate. Plots of various Marshall Parameters such as Marshall Stability, Flow value, voids filled with bitumen, voids in mineral aggregates and unit weight against the bitumen content shows an improving trend of parameters with increasing the plastic replacement. Comparison with earlier published result shows that increasing the plastic replacement beyond 12% will have a negative influence on stability value. The recycling of e-waste plastic and marble dust in asphalt mix design for pavements provide us a better way of resource utilization in a cost-effective manner. Page(s): 36-45