In-situ characterization of highly reversible phase transformation by synchrotron X-ray Laue microdiffraction
Abstract
The alloy Cu25Au30Zn45 undergoes a huge first-order phase transformation (6% strain) and shows a high reversibility under thermal cycling and an unusual martensitc microstructure in sharp contrast to its nearby compositions. This alloy was discovered by systematically tuning the composition so that its lattice parameters satisfy the cofactor conditions (i.e., the kinematic conditions of compatibility between phases). It was conjectured that satisfaction of these conditions is responsible for the enhanced reversibility as well as the observed unusual fluid-like microstructure during transformation, but so far, there has been no direct evidence confirming that these observed microstructures are those predicted by the cofactor conditions. To verify this hypothesis, we use synchrotron X-ray Laue microdiffraction to measure the orientations and structural parameters of variants and phases near the austenite/martensite interface. The areas consisting of both austenite and multi-variants of martensite are scanned by microLaue diffraction. The cofactor conditions have been examined from the kinematic relation of lattice vectors across the interface. The continuity condition of the interface is precisely verified from the correspondent lattice vectors between two phases.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 23, 2016
- Source ID
- 10.1063/1.4951001
Entities
People
- Alastair Macdowell
- Nobumichi Tamura
- Richard D. James
- Xian Chen
Organizations
- Air Force Office of Scientific Research
- Hong Kong University of Science and Technology
- Lawrence Berkeley National Laboratory
- Office of International Science and Engineering
- Office of Naval Research
- Research Grants Council, University Grants Committee
- University of Minnesota