Research at SRM University-AP shows that applying a composite coating of chromium aluminum carbide (CR2 ALC) to the engine piston rings not only improves piston performance but also increases engine life, efficiency and lubrication. The university obtained a patent for the same under the title “NICKEL MOLYBDENUM ALUMINIUM (NIMOAL) – CHROMIUM ALUMINIUM CARBIDE (CR2ALC) MAX PHASE COMPOSITE COATINGS FOR AUTOMOTIVE APPLICATIONS AND A METHOD FOR MAKING THE SAME”.

For any vehicle to run efficiently for a long time, its engine must be good. The rings on piston further improve the engine performance. It is in this context that many efforts are being made by scientists to develop piston rings with the new scientific technologies. Dr Sheela Singh, Associate Professor in the Department of Mechanical Engineering at SRM AP, has been conducting comprehensive research on the subject for three years with research student Deepak Davis.

The piston rings of motor vehicles currently on the market have a coating with nickel molybdenum aluminum. SRM University-AP researchers say it would be better to use a composite coating made with chromium aluminum carbide instead. If the piston rings have high velocity and lubrication properties, their rigidity is good and it is better to use chromium aluminum carbide (CR2LC).

The Patent Certificate is issued by the Patent Office, Government of India, after thorough examination. University President Dr Satyanarayanan, Vice-Chancellor Prof V S Rao, Pro Vice-Chancellor Prof D Narayana Rao and others lauded Dr Sheela Singh and Deepak Davis for their fervent research and innovation. This is the second patent granted to SRM University-AP.

Bird strikes are a crucial phenomenon that should be taken into consideration while designing aircraft. Bird strikes have been reported since the early days of flight causing fatal disasters. It is estimated that around 300 people were killed, and several aircraft were destroyed because of bird strikes. A great deal of research has been conducted to tweak the design of aircraft to bring down the impact of bird strikes. Prof Prakash Jadhav and his PhD scholar Gruhalakshmi Yella from the Department of Mechanical Engineering have published a paper offering an appropriate solution in this regard.

Their paper titled “Hybrid joint interface in composite fan blade subjected to bird strike loading” has been published in the international journal, ‘Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science’ having an impact factor of 1.76. The research puts forward an ideal solution to alter the design of the aircraft fan blades which are frequently being subjected to such collisions. The duo proposes a hybrid joint interface using two fibres instead of a single fibre.

Some delamination failures observed in the trailing edge of the blades could probably increase the effect of such bird strikes. For rectifying the delamination problem, the proposed solution is to use a material with higher strain capability such as glass fibres in the areas on the fan blade which are prone to delamination, while maintaining carbon material on the remaining blade. The concept is proved by first performing a static analysis on 3D FEA coupons with an in-built hybrid interface joint and next by performing a dynamic bird strike analysis on 3D FEA coupons and sub-element models with an in-built hybrid interface.

Abstract of the Research

Fan blades are one of the most important components of an aircraft engine. Bird strikes on fan blades have always been a cause of worry and it can cause slices of birds to hit other parts of the engine which may lead to greater damage. Bird strikes cannot be completely avoided. Although current composite blades can withstand the bird strike impact, some delamination failures are still observed on the trailing edge side of the blade, possibly due to vibration bending modes. This paper talks about using two fibres in a composite blade instead of the current single fibre one. For this to be feasible, two fibre joints at various locations on the blade must be properly designed. The design criteria used here is the lowest inter-laminar shear strain level at critical joint locations.

Dr Prakash Jadhav, Professor and Head, Department of Mechanical Engineering at SRM University-AP has published a chapter titled “Design Methodologies for Composite Structures in Aircraft Engines” in the book Advanced composites in aerospace engineering applications, Feb 2022, ISBN 978-3-030-88191-7, Springer.

Abstract of the book chapter

Recently there have been many successful attempts to implement the use of fibre-reinforced composite structures in commercial aircraft engines. The author has been part of these efforts while working in the aviation industry. This article describes these efforts to design, analyze, manufacture, and implement the composite structures inside the low-pressure and low-temperature zones of the engine. Very innovative out-of-the-box design methodologies were used to design these components. These efforts elaborate on the design, optimization, and improvement of the composite fan blade, the composite fan platform, and the composite booster blade inside the engine. It focuses on structural design, aerodynamic efficiency, and specific fuel consumption improvement efforts along with the usual reduction of weight targets. This work successfully demonstrates the systematic steps in the design and implementation like preliminary coupon-level simulations, coupon-level manufacturing, coupon/prototype testing, and final part-level simulations followed by part tests.

The target readers for the book are all engineers, professionals and researchers from the aerospace field. Dr Prakash Jadhav’s future research plan is to continue to develop new methodologies to implement more composites into the aerospace industry. The book chapter will be extremely useful for engineers working on the design of composite structures for aerospace applications.

High-entropy alloys (HEAs) are gaining research significance in recent times as they propose novel alloy designs and concepts demonstrating better performance. HEAs constitute multiple principal elements in varying concentrations and combinations to produce new materials with excellent physical properties and superior performance at extreme temperature conditions. Recent studies have brought out a few high-entropy alloys possessing exceptional properties, even capable of challenging the existing theories and models for conventional alloys. However only very little has been explored within this multidimensional space leaving limitless possibilities to be explored and materialized.

Dr Sheela Singh, from the Department of Mechanical Engineering, has been conducting rigorous research in this domain and she has published research articles proposing novel ideas to tweak the properties of HEAs. In one of the articles co-authored by Dr Sheela, “Effect of minute element addition on the oxidation resistance of FeCoCrNiAl and FeCoCrNi2Al high entropy alloy”, published in the journal Advanced Powder Technology, she investigates the effect of Ti0.1 and Ti0.1Si0.1 addition on the high-temperature isothermal oxidation behaviour of dense FeCoCrNiAl and FeCoCrNi2Al high entropy alloys.

Mechanical properties such as hardness & young’s modulus, thermal properties such as melting temperature, specific heat capacity and coefficient of thermal expansion (CTE) were investigated by Nano hardness tester (NHT), differential scanning calorimetry (DSC) and dilatometer, respectively. The phases present in the HEAs produced by hot vacuum pressing and after isothermal oxidation were characterized by X-ray diffraction, Scanning Electron Microscopy and Raman Spectroscopy.

The weight gain recorded after isothermal oxidation for 5,25,50 and 100 hours at 1050°C was found to be parabolic in nature. X-ray diffraction analysis (XRD), as well as Raman spectroscopy analysis of HEA’s oxidized at 1050°C for 100 hours, shows the formation of the Al2O3 phase. A homogeneous thin oxide scale without any discontinuity was observed throughout the cross-section. It has been confirmed that Ti & Si addition in minute amount (0.1 at. % each) improves the mechanical properties and oxidation resistance as well as reduces the waviness of the oxide scale.

Another article co-published by her, “Enhanced Magnetization with Increased Chromium Concentration in FeCoCrxNi2Al High-Entropy Alloy”, in Materials and Science Technology, reports the effect of increasing the concentration of antiferromagnetic element Cr in FeCoCrxNi2Al (x = 0.5, 1.5) High Entropy Alloy (HEA) on their magnetic properties. It was found that the structure and composition of different phases, and the likely degree of spinodal decomposition in the Cr-Fe rich BCC phase significantly affects the magnetic properties.

Interestingly, the sample with Cr concentration x=1.5 showed two times larger saturation magnetization as compared to x=0.5. Furthermore, the magnetization versus temperature response shows a multi-phase character and exhibits distinct behaviour in low temperature and high-temperature regimes in both samples. The obtained soft ferromagnetic behaviour of these HEAs is crucial for the development of a new class of HEA for various applications.

The considerable structural and functional potential, as well as the richness of design, make HEAs promising candidates for new applications prompting further studies in the field. There remains a vast compositional space that is yet to be discovered. New studies have to be initiated finding out effective ways to recognise regions within this space where high-entropy alloys with potentially interesting properties may be lurking. Dr Sheela’s research is a right step in this direction to pave the way for fruitful developments in the future.