Move aside plastics

K. Anantha Padmanabhan, Mercator Professor of DFG (German Research Foundation) at the Institute of Materials Physics, University of Muenster, Germany and a former director of IIT Kanpur speaks to Mohit Kumar Jolly on 'superplastics', science education and doing science in India.

doi:10.1038/nindia.2009.316 Published online 27 October 2009

K. Anantha Padmanabhan

Q: How do you rate the growth of R & D sector in India?

A: The growth of R&D sector, especially in engineering, has not been so great. Indian industries lack confidence. They always prefer shortcuts and buy foreign technology paying through their nose, but do not allow a young man to try novel technology. It takes time to absorb imported technology.

Around 100 Indian companies are competent on a global scale. They have a well-defined path and good growth rate, but the first and second level leadership is often not of a very high quality in India. There is another problem with the Indian philosophy that's holding our R&D back – strong condemnation for failure. If the Indian team fares badly in a T20 series, we burn effigies of the players!

Q: What is your stand on undergraduate research in India?

A: Without a good foundation, you can't build a skyscraper. Undergraduate studies are that foundation, in which research should not only be introduced, but also be taken seriously. Opportunities should be developed and challenges should be posed to students at the earliest stage, what earlier stage can there be than the UG level?

Q: Please elaborate on some basic fundamentals of superplasticity and your research.

A: Superplasticity is something more than plasticity. It arises under special microstructure conditions -- when grain size gets very small (close to a few micrometers down to a few nanometers), they slide past each other without any distortion. Normally the best available materials are 40%-50% ductile, but under superplastic conditions, tensile deformation of the order of a few thousand percent can be obtained in metals and you can draw them to a point. You can make a metal behave like a chewing gum.

Q: You have also outlined a new field of research 'mechanics of superplasticity'.

A: We (Russian Professor R. A. Vasin, his student F.U. Enikeev and I) have outlined this new field. It is a very tricky – you are simultaneously solving 10-12 equations in a self-consistent way. Mechanics of superplasticity comes under mechanics of solids, where you have boundary value problems, flow, force and conservation equations to be simultaneously solved. Since superplasticity is achieved at high temperatures, thermal balances also have to be kept into mind. This is a very complex field, where same set of equations have to be invariant (same in all frames of reference), and so it becomes a formidable problem.

Q: What are its applications?

A: 108 parts of the B1 bomber were replaced by a single part through superplasticity reducing costs by 50% and weight by 30%. Using superplasticity, turbine discs of nickel alloys can be made at nearly 100% material utilization. Aluminum superplastic alloys are being mainly used in automobiles and rails. Plastics are getting replaced by superplastics and the transportation sector stands to benefit immensely.

Q: Where is your technology being put to best use?

A: India had no nickel deposits in the 90s and there were no international standards for stainless steel. US, after the World War II, had developed stainless steel with 4.5% nickel instead of 8%. India developed stainless steel with 1% nickel, and today we export thousands of tons of it.

At the Vikram Sarabhai Space Center in Thiruvananthapuram, we set up the facility to superplastically form hemispheres of 415 mm diameter. Water tanks were made using Al 7020 alloy in IIT Madras. This work was of relevance to the Liquid Propulsion System Center of ISRO.

We also transferred superplastic forming technology to Hindustan Aeronautics Limited (HAL) and I did some defense-related work for DRDL as also IGCAR, Kalpakkam to characterise the properties of fast breeding reactor construction materials.

Q: What about your related research in nanosciences and nanotechnology?

A: Studying the deformations of many types of nanomaterials since 1994, we have also introduced the concept of 'mesoscopic grain boundary sliding' (how grains deform collectively). Presently, I am trying to extend this idea to understand the deformation of bulk metallic glasses, which under certain conditions behave like nanomaterials or superplastics.

K. A. Padmanabhan is first Indian to receive the 'FORSCHUNGSPREIS' of the Alexander von Humboldt Foundation and the first Indian engineer to be conferred the Sc. D. degree (Doctor of Science) by University of Cambridge, UK for his research contributions. He has also been the Dean of Academic Research at IIT Madras.

Mohit Kumar Jolly is an undergraduate student in the Department of Biological Sciences and Bioengineering at IIT Kanpur.