In situ nanoscale visualization of peritectic reactions
Abstract
All technological materials start their lifetimes in the liquid phase. During cooling, the liquid either converts directly to the solid phase, or the liquid reacts with one solid phase to yield another solid phase of a different structure. The latter reaction is known as a peritectic transformation and is responsible for producing many of the materials that have built our world, including steel, brass, and bronze. Despite the ubiquity of these alloys, our understanding of the mechanism of peritectic solidification is speculative at best, requiring major assumptions of the transient interactions between the two solid phases in the liquid. A further complication is that peritectic alloys show a surprisingly wide range of patterns in the cast state, from striped to tree-like structures. What is the origin of these diverse patterns? Is each the result of unique causes and effects, or are there unifying physical principles that govern their growth and form? The objective of this project is to understand at a fundamental level the dynamics of the peritectic reaction in metal alloys. To this end, the principal investigator (Shahani) will visualize in real-time and in unprecedented detail the microstructural evolution during peritectic solidification, by taking advantage of the world’s brightest source of X-rays at Brookhaven National Laboratory together with state-of-the-art computational algorithms. His imaging approach represents a major breakthrough in materials characterization, operating at the extremes of spatial and temporal resolutions in order to capture the reaction as it transpires. The experimental data will provide direct and conclusive evidence on the nucleation and growth modes of peritectics, and the impact of processing conditions on pattern selection. This information can also be used to inform, parametrize, and validate simulations, enabling materials scientists and engineers to better predict and control the products of the peritectic reaction.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110260
Entities
People
- Ashwin Shahani
Organizations
- Air Force Office of Scientific Research
- Board of Regents of the University of Michigan
- United States Air Force