|About this Abstract
||3rd World Congress on High Entropy Alloys (HEA 2023)
||Tensile Creep Behavior of a Nb45Ta25Ti15Hf15 Refractory High-entropy Alloy
||Gianmarco Sahragard-Monfared, Calvin Belcher, Mingwei Zhang, Cheng Zhang, Andrew Minor, Diran Apelian, Enrique Lavernia, Jeffery Gibeling
|On-Site Speaker (Planned)
The tensile creep behavior of a plasma arc-melted and cold-rolled Nb45Ta25Ti15Hf15 refractory high entropy alloy was investigated at temperatures ranging from 1123-1223 K and constant true stresses ranging from 50-300 MPa. A stress exponent of 1.2 was observed at low applied stresses, while at high applied stresses, the exponent was 5.7. TEM analysis on creep samples interrupted at steady-state deformation revealed the control of long straight screw dislocation motion, contrary to the conventional power-law creep interpretation. The creep data was better described by an exponential equation, indicating thermally activated glide of screw dislocations. Samples that crept at lower applied stresses and longer time were affected by phase decomposition and Hf-oxide formation at grain boundaries, reducing creep ductility and life. Under higher applied stresses, Nb45Ta25Ti15Hf15 exhibited superior creep resistance and excellent creep ductility compared to TiNbHfZrTa (Senkov alloy) and FCC MPEAs.
||Planned: Metallurgical and Materials Transactions