|About this Abstract
||1st World Congress on High Entropy Alloys (HEA 2019)
||High Entropy Alloys 2019
||Local Chemical Ordering and the Mechanical Properties of CrCoNi-based High-entropy Alloys
||Robert O. Ritchie, Mark Asta, Andrew M. Minor, Qian Yu, Jun Ding
|On-Site Speaker (Planned)
||Robert O. Ritchie
CrCoNi-based medium/high-entropy alloys can display exceptional combinations of strength (~1 GPa), ductility (~60-90%) and toughness (>200 MPa√m), properties which are further enhanced at cryogenic temperatures. In situ TEM observations identify multiple deformation mechanisms, associated with their high friction stress yet low stacking-fault energy, that act synergistically to generate damage-tolerance. The effect of local chemical ordering appears to be important here. DFT-based Monte-Carlo simulations and now MD simulations show that variations in local chemical order have a profound effect on the stacking-fault and twin-boundary energies, the TRIP effect, and the formation energy of point defects, all features that influence mechanical properties, although convincing experimental verification of the presence of such local order is rare. Here we discuss the notion of “tuning order in disorder” to achieve a science-based optimization of high-entropy alloys with specifically desired macroscale mechanical performance.