We now extend our horizon to “ High-Entropy Materials” following the previous “High-Entropy Alloy” group. With great thanks to Dr. Li, Dr. Ponge and all group members for their contributions, please keep on following our new group and the upcoming works.
Figure 1: Strength-ductility profiles of various classes of metallic materials including our recently developed HEAs.
The goal of our group was to develop novel high-entropy alloys (HEAs) with exceptional mechanical, physical and chemical properties based on the understanding of their structure-properties relations. This was achieved by using the advanced experimental techniques and the state-of-the-art theoretical methods.
Conventional alloy design over the past centuries has been constrained by the concept of one or two prevalent base elements. As a breakthrough of this restriction, the concept of HEAs opens a new realm of numerous opportunities for investigations in the huge unexplored compositional space of multi-component alloys.
As a typical example shown in Figure 1, while conventional alloys use strengthening mechanisms such as grain boundaries, dual-phase structure, dislocation interactions, precipitates and solid solution (e.g. steels, Ti-alloys, Al-alloys), our recently developed novel interstitial TWIP-TRIP-HEAs concept combines all available strengthening effects, namely, interstitial and substitutional solid solution, TWIP, TRIP, multiple phases, precipitates, dislocations, stacking faults and grain boundaries. This leads to the exceptional strength-ductility combination of the novel HEAs, exceeding that of most metallic materials.
Our research group (High-Entropy Alloys) conducts the state-of-the-art research work employing novel experimental-theoretical methodologies (e.g., EBSD, ECCI, FIB-APT, TEM, Calphad and DFT; Figure 2) in the following specific aspects:
Excellent strength-ductility combination of transitional metal HEAs;
Resistances to hydrogen-embrittlement and corrosion of HEAs
Light-weight high-strength HEAs
High-temperature refractory high-strength HEAs
Multifunction of HEAs
Defects, segregations and thermodynamics in HEAs
In-situ observation of deformations in HEAs under electron microscopes
These aspects are strongly interconnected and facilitate an extensive collaboration network with national and international experts.
Figure 2: Representative microstructural information obtained from an interstitial TWIP-TRIP-HEA sample by combining multiple advanced characterization techniques. ECCI: Electron channeling contrast imaging; EBSD: Electron backscatter diffraction; TEM: Transmission electron microscopy; APT: Atom probe tomography; TWIP: Twinning-induced plasticity; TRIP: Transformation-induced plasticity.
Figure 2: Representative microstructural information obtained from an interstitial TWIP-TRIP-HEA sample by combining multiple advanced characterization techniques. ECCI: Electron channeling contrast imaging; EBSD: Electron backscatter diffraction; TEM: Transmission electron microscopy; APT: Atom probe tomography; TWIP: Twinning-induced plasticity; TRIP: Transformation-induced plasticity.
Guo, Y.; Jia, L.; He, J.; Zhang, S.; Li, Z.; Zhang, H.: Interplay between eutectic and dendritic growths dominated by Si content for Nb–Si–Ti alloys via rapid solidification. Journal of Manufacturing Science and Engineering, Transactions of the ASME 144 (6), 061007 (2022)
