The speaker and his research group summarize recent theoretical and experimental work on the discovery of highly reversible transforming alloys. These are poised to play a major role in diverse areas of technology, and give rise to fascinating mathematical questions. Big first order phase transformations in solids can be highly reversible, if the lattice parameters are “tuned” to satisfy certain relations that promote the compatibility between phases. They outline the basic theory behind this tuning and give examples of recently discovered alloys. One of these alloys has thermal hysteresis as low as 0.2°C despite having a 6% transformation strain. Another very recent example exhibits exact reproducibility of full stress-induced hysteresis loops even after 10 million cycles of stress-induced transformation at a peak tensile stress (each cycle) of 400 MPa. They use this kind of tuning to find some interesting new reversible alloys, which can be used in diverse ways for the direct conversion devices, and provide interesting possible ways to recover the vast amounts of energy stored on earth at small temperature difference.
About the speaker
Prof Richard D James received his PhD in Mechanical Engineering from the Johns Hopkins University in 1979. He joined Brown University as an Assistant Professor of Engineering in 1981 and moved to University of Minnesota in 1985, where he is currently the Distinguished McKnight University Professor.
Prof James’ research focuses on phase transformations in materials - especially shape memory and multiferroic materials - at large and small scales. This involves the development of mathematical methods for the analysis of materials at atomic and continuum scales, especially the development of multiscale methods for understanding the relation between the behavior of materials on different scales. It also involves advanced methods of bulk synthesis and characterization of new materials in his laboratory, guided by theory.
Prof James is the recipient of several prizes including the Brown Engineering Alumni Medal by Brown University (2009); the William Prager Medal by the Society of Engineering Science (2008); and the Warner T. Koiter Medal by the American Society of Mechanical Engineers (2008). He was also elected a Fellow of the American Academy of Mechanics (1997).
For attendees’ attention
The lecture is free and open to all. Seating is on a first come, first served basis.
Light refreshments will be served from 4:30 to 5:00 pm.
