MICROSTRUCTURE DESIGN FOR MULTI-PHASE HIGH-ENTROPY ALLOYS
Abstract
While the original efforts in HEA development have focusedon searching single-phase disordered solid solutions, the most recent efforts have been devoted to multi-phase HEAs because stable single-phase solid solution HEAs are (a) rare and (b) not suitable for high-temperature applications. Multi-phase HEAs, while retaining the “high entropy” nature of the parent matrix, contain stable ordered intermetallic phases and hence high-density hetero-phase interfaces that will regulate dislocation and twinning activities. However, phase transformation pathways in MPE systems leading to multi-phase microstructures are also an uncharted territory. In addition to the conventional nucleation and growth mechanism and eutectic/eutectoid reactions, ample non-conventional transformation pathways may be encountered, including concurrent spinodal decomposition and spinodal ordering, conditional spinodal, pseudo-spinodal, etc. In this proposal, leveraging heavily ongoing experimental and CALPHAD modeling efforts on multi-phase HEAs research at AFRL, UNT, OSU, and many other places, we plan to investigate complicated transformation pathways leading to desirable two-phase or multi-phase microstructures in refractory as well as low-density HEAs for high-temperature aircraft structural applications. The approach will be an integration of phase field microstructural modeling with CALPHAD thermodynamic modeling, fully motivated and informed by the ongoing experimental efforts. Typical multi-phase HEAs to be investigated will include bcc+B2 and fcc + L12 + B2 systems.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010015
Entities
People
- Yunzhi Wang
Organizations
- Air Force Office of Scientific Research
- Ohio State University
- United States Air Force