Any reliable technology stands on sound scientific foundation. Being an academic research lab, scientific understanding comes first. Our research group focuses on three major field of researchs: Composites, Field assisted processing, and Machine learning. While appearing disconnected at first sight, they are pieces of the same jigsaw puzzle, commonly known as "Material's Tetrahedron". This tetrahedron emphasizes on four independant pillars in developing technologies that we can depend on: Structure, Processing, Properties and Performance.

Crystal structure and processing technique determine the final properties of materials. But as learn from Ashby's Material selection Maps, there are always trade-off in properties. For example, hard materials have limited ductility. To overcome this natural challenge, we design composites of complementary materials and take advantage of field assisted processing to achieve desired performance. Machine Leaning and FEM (finite element method, YouTube Video) are used as tools to understand and simulate the corelations among the corners of the Tetrahedron.

Ashby’s maps highlights the need for composite designs where materials of different properties (often contrasting) are stitched together to provide superior properties. Properties that no single material exhibit, kind of Meta-material. Nature, being the greatest designer/architecture has done it over and over again, giving rise to a new field of study "Bio-inspired designs."

A very simple example of a composite, human bones , is a composite of hard mineralized tissue (cortical) and soft organic elastic fibers (collagen). The hardened matrix, formed by Calcium Hydroxylapatite, grows into an open-lattice structure that allows blood vessels. This unique design and composition allows bones to be hard and fracture resistant while being light-weight. Additionally, it is also functionally graded material with hard cortical bones on the surface and spongy Trabecular bone inside. An idea that has been adopted in TMT ( Thermo Mechanically Treated) steel bars, used to reinforce concrete (another example of popular composite). We design the structure of composites made up of metal-ceramic-polymers for armor, functionally graded materials, thermal barrier coating and shock absorption applications.

Field Assisted Processing

Ceramic parts are primarily fabricated by sintering. Sintering is a process in which powders of desired material are first compacted into desired shape and then fired to a high temperature. High temperature facilitates the diffusion of constituent particles into a solid dense mass. Sintering, in the form of pottery, is one of the oldest invention of human civilization. However, the process has changed little until a few decades ago when our scientific understanding of sintering mechanisms improved. Researcher showed that pressure, rapid heating and microwave heating can not only shorten the processing time but also improved the properties of fabricated material. The field assisted sintering (also known as Flash Sintering) is the latest addition to the list, in which we apply electric field directly to the ceramics (at relatively lower furnace temperature).

In the figure accentuates the role external fields play in reducing the energy consumption and time required for processing, by introducing a new path for duffusion)create non-equilibium crystal structural changes that give rise to novel properties, even in traditional ceramics. For a typical case of 3 mol% yttria stabilized zirconia, as we move from convention sintering to pressure assisted (hot press), Microwave (MW), Spark plasma sintering (SPS) to flash sintering, the sintering temperature dropped from 1500 C to 800 C. The right most figure shows that as we apply higher and higher electric field (DC voltage)the sintering temperature drops and densification rate enhances.

Our hypothesis is that these externally applied fields (shown in red)create non-equilibium crystal structural changes that give rise to novel properties, even in traditional ceramics. play in reducing the energy consumption and time required for processing . We are working to come up with a unifying theory which can explain the field-matter interactions, and to harness this understanding to thermal barrier coatins (TBC), functional ceramics, and storage devices (batteries).

There isn't any active field of research that is not utilizing Machine learning (ML) or Artificial Intelligence (AI) to unravel the emperical relationships between the causes and the effects. In material science, ML is finding applications in understanding phase evolutions for complicated systems, predicting material properties of new alloy compositions, ML aided molecular dynamic simulations, corelating properties to the processing history, Microstructure analysis, to name a few (link).

In our lab, we are using Neural Networks, Random Forest and UNET along with Finite Elemental Method (FEM) simulation to formulate the processing parameters and intelligent designs of composites. Our group is currently working on grain boundary detection , orientation of pearlitic lamellae, intelligent phase identification, peak fitting of X-ray diffractions.

Science is the systematic study of natural phenomena, while technology uses scientific discoveries to create device and equipment to solve a probem or further our understandings. In simpler words, technology helps in scientific discoveries and good science leads to development of new technologies. We, being a Technological institute, are committed to design products and processes that can serve the society well. Accordingly, we work on the projects involving technological applications of the Sciences we are involved in.

Oxygen Concentrator