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The project aimed to develop and optimize Austempered Ductile Iron (ADI) technology for use in the agricultural and automotive industries in India. The objectives included studying the mechanical properties of ADI, developing cost-effective production processes, and evaluating its potential applications in Agricultural and Automotive Industry in India.

Two types of bone plates have been designed and developed from ZM21 Mg Alloy for the forearm of an adult- non-perforated bone plate and perforated bone plate. The WEDM (for machining contours of bone plate) and EDD processes (for creating interconnected micro-holes in bone plate) used in the development have been optimized for better surface integrity, low degradation rate and apatite formation rate in biological fluid over the expected bone healing period. A comprehensive study on the mechanical integrity loss (i.e, elastic modulus, compressive strength, fatigue strength, bending strength and fracture toughness) of perforated and non-perforated bone plates at regular intervals during complete degradation test period. Correlation between processing parameters (WEDM & EDD) have been established with surface characteristics, degradation rate, apatite formation rate and mechanical integrity of ZM 21 Mg-alloy to predefine the life span of bone plate.

The project form TRRL was undertaken the development of PDE combustor with flow control system, fire control system and data acquisition from the no of tests. The development was undertaken successfully and the firing proved to be consistent every time. The data w.r.t pressure and thrust was captured for the tests and the performance curves were obtained.

The project form ARDB was undertaken for analysis and optimization of pulse detonation engine parameters experimentally. The combustion tube length, diameter, Schelkin spiral dimensions were optimized for maximum thrust obtained from the PDE. Flow control and fire control systems were developed and used for the purpose. The installation of PDE as a sustainer in a missile was also undertaken and found that it can be integrated.

The aim of this proposal is to develop high Curie temperature lead free piezoceramics with superior piezoelectric properties. It is of our national importance to design, develop and scale up high Curie temperature lead free piezoceramics with superior piezoelectric properties. PI and his group will contribute to this through improvements, reliability and by improving the understanding of high Curie temperature lead free piezoceramics. Further impact derives from the training of early career researchers, employed in this project, who will provide the skills to transfer high Curie temperature lead free piezoceramics based technologies from academia to industry.

In this project, we will achieve the following goals:

• Curie temperature upto 450°C in chemically modified lead free BiFeO3-BaTiO3 solid solutions
• piezoelectric coefficient upto 200 pC/N in chemically modified lead free BiFeO3-BaTiO3 solid solutions
• A prototype piezoelectric vibration sensor (demonstration only) will be designed in consultation with domain scientist.

The project will also be benefitted from applicant’s existing links and joint research activities with Dr. O.P. Thakur, SSPL-DRDO, Prof. Rajeev Ranjan, Materials Engineering, IISc Bangalore, Prof. Ashish Garg, Materials Science and Engineering, IIT Kanpur and Dr. A.R. James, DMRL-DRDO.

The aim of this proposal is to develop lead free relaxor ferroelectric materials with enhanced power density, very short discharge time, high breakdown strength for possible pulsed capacitor applications.

Materials with high power density and energy density are becoming gradually significant due to swift growth of advanced pulsed power systems for applications such as hybrid electric vehicles, high frequency inverters, space vehicle power systems, medical devices, electromagnetic rail guns etc, Energy storage devices mainly comprise of Fuel cells, lithium ion batteries, electrochemical capacitors and electrostatic capacitors. Batteries possess enormously high energy density but their output power is limited by the low mobility of charge carriers, which further restricts their application in pulsed power systems. Due to fast polarization response under an applied external electric field, dielectric materials exhibit very high charge/discharge speed which further results in a huge output power density of the order of MW.

From the last decade, relaxor ferroelectrics possess negligible Pr (remnant polarization), low coercive field and high Pmax (maximum polarization) due to their characteristic polar nano regions (PNRs), which further results in high energy density and efficiency. Therefore, the relaxor ferroelectrics are appreciated candidates in the field of energy storage applications. It is experimentally evidenced that DBS of bulk ceramic is associated with the microstructure, such as grain size, grain boundary condition, porosity etc. Among these, grain size contribution is quite prominent. Tunkasiri calculated the effect of grain size on DBS of the ceramic; E_DBS∝1/√G where, EDBS is the DBS of the ceramic and G is the grain size of the ceramic. To achieve our goal, the proposed research will concentrate on the following specific objectives:

• To optimize the composition for the lead free (Bi0.5Na0.5)TiO3–BaTiO3 [NBT-BT] based solid solutions to achieve high value of breakdown strength > 200 kV/cm and recoverable energy density > 2 J/cm3.
• To study the effect of aging on power density and energy storage efficiency.
• To design and develop a pulse power capacitor with capacity ~1000 pF, operating temperature range -30 to +100°C, Vmax (DC) ~30kV.

We have synthesized the PZT and Nb doped PZT samples using solid state reaction method. XRD studies clearly depict that there is no impurity phase present in the samples. Dielectric measurements show that the dielectric constant was below 500 as required for ferroelectric generator (FEG) applications. Ferroelectric measurements show that the remnant polarization for all samples is above 25 µC/cm2. We have also achieved high density to samples to become good candidate for FEG applications.

Magnetoelectric composites have sparked a lot of interest in order to produce high magnetoelectric coefficients in bulk and layered composites using different techniques. A wide range of magnetostrictive and piezoelectric phase combinations have been studied in the past, with lead (Pb) based materials being used as the piezoelectric component due to their strong piezoelectric response. However, many investigations focused on developing lead-free ferroelectric systems with electrical properties equal to those of lead-based systems due to environmental concerns.

The objective of this project is to achieve the requirements for a good magnetoelectric effect in a lead-free composite. In this study, phase structure, dielectric properties, magnetic properties and magnetodielectric have been investigated and analyzed the magnetoelectric coupling coefficient of the composites. In layered composites, we also discovered the self-biasing phenomenon, which allows considerable ME coupling in the absence of a DC magnetic field. The elimination of the necessity for DC magnetic bias in ME composites opens up a lot of opportunities for the development of components for a variety of applications. The ME coefficient is also greatly influenced by the thickness fractions of the two phases, thus we optimised the longitudinal and transverse ME response by altering the thickness of both BCZT and NZCF layers in the next work.

In this project, we have synthesized a non-Pb piezoelectric system BZT-BCT, which exhibits a very high piezoelectric coefficient (d33) of 512 pC/N at MPB, which is comparable even with high-end PZT. Lead-free BZT-xBCT samples were prepared using the solid-state reaction technique. Structural analysis shows the presence of orthorhombic and tetragonal phases in the prepared samples. We observed that with an increase in x content, the tetragonal phase increases which further results in higher d33. Sintering temperature plays a very important role to achieve desired density, which further leads to good piezoelectric properties.

Meanwhile, we have also introduced a novel method to obtain high piezoelectric coefficient and electromechanical coupling coefficient in BZT-BCT by introducing a novel synthesis procedure. We observed high d33~ 520 pC/N and electromechanical coupling coefficient ~ 57.5% in 0.5BZT-0.5BCT synthesized by novel synthesis procedure.

For energy storage efficiency, we prepared BZT-BCT by sol-gel technique. The different parameters like dielectric constant, dielectric loss, polarization, coercive field, the efficiency of energy storage were found to be optimum for the (1-x)BZT-xBCT ceramics at x =0.55. We estimated the energy storage density W~ 189 mJ/cm3 and high efficiency η ~ 75.6% for BZT-0.55BCT ceramic composition. Therefore, this work suggested that 0.45BZT-0.55BCT ceramics are potential candidates for energy storage capacitor.

Furthermore, we investigated the temperature stability of 5% (Mg1/3Nb2/3)4+ doped BZT-BCT composition at 50kV/cm. We observed Wrec ~ 235 mJ/cm3and ultra-high η~ 94.3% at room temperature. The η of ceramic increases to 94.6% and Wrec to 187 mJ/cm3 as the temperature rises to 110°C.

A design concept for making sandwich panel for blast mitigation was developed such that the designed material should be able to absorb the maximum of blast energy by undergoing elastic, plastic and fracture. Design concept include the specifically designed perforated face sheet so that after interacting with blast wave it doesn’t leave any splinters off. The specific light weight alloy of aluminum (AA6061-T6) was selected for making front and back sheet (both of 2mm thickness) of sandwich panel. Closed cell Aluminum alloy foam (AA6061) was used as central soft core. The foam was synthesized on stir casting furnace by melt route. The synthesized foam was cut into slices and sandwiched between face sheet and back sheet. The pressure value correspond to equivalent quantity of TNT and stand-off distance was investigated by simulation method. Quasi-static compression test and High strain rate test on Split Hopkinson Pressure Bar apparatus for face sheet material, central foam and back sheet material was performed to know the compressive strength. Face sheet and back sheet was tested individually on Shock tube at 46 bar reflected pressure and were analyzed. A sandwich panel was designed (11mm thick foam) and tested on shock tube which completely deformed plastically thereby absorbing some part of incident energy. Its blast mitigation capacity was increased by increasing the central foam thickness to 22 mm which resulted in very little deformation and 75.84% increase in mitigated transmitted pressure was recorded. The stress wave and strain behavior due to shock wave interaction were studied by Ansys fluent software.