|About this Abstract
||3rd World Congress on High Entropy Alloys (HEA 2023)
||Strength and Thermal Stability of Mechanically Driven Nanocrystalline High Entropy Alloys
||Yuan Yao, Luyan Li, Mostafa Hassani
|On-Site Speaker (Planned)
Nanocrystalline materials are featured by ultra-high strength but have strong tendency of grain coarsening, while high entropy alloys provide stable microstructures due to sluggish diffusion. Nanocrystalline high entropy alloys (nc-HEAs) are expected to combine the benefits of these two worlds, further pushing the performance limits of structural materials. Here we use forced mechanical mixing to fabricate a nc-HEA in solid state. Nanoindentation is used to measure the strength of the alloy and evaluate its strain rate sensitivity. The thermal stability of the alloy is also studied with isochronal and isothermal annealing experiments. We find significant contributions from grain boundary and solid solution strengthening and discuss the strain rate sensitivity of the nc-HEA in light of the interplay between the two mechanisms. We also find excellent grain size retention as well as some unexpected increase in the hardness after annealing which we attribute to the second phase precipitations in the material.
||Planned: Metallurgical and Materials Transactions