High-Entropy Alloys

High-Entropy Alloys

The goal of our group is to develop novel high-entropy alloys (HEAs) with exceptional mechanical, physical and chemical properties based on the understanding of their structure-properties relations. This is being 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.

Key Publications

Rao, Z.; Springer, H.; Ponge, D.; Li, Z.: Combinatorial development of multicomponent Invar alloys via rapid alloy prototyping. Materialia 21, 101326 (2022)
Guo, Y.; He, J.; Li, Z.; Jia, L.; Wu, X.; Liu , C.: Strengthening and dynamic recrystallization mediated by Si-alloying in a refractory high entropy alloy. Materials Science and Engineering A: Structural Materials Properties Microstructure and Processing 832, 142480 (2022)
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)
Ge Wu, Chang Liu, Andrea Brognara, Matteo Ghidelli, Yan Bao, Sida Liu, Xiaoxiang Wu, Wenzhen Xia, Huan Zhao, Jing Rao, Dirk Ponge, Vivek Devulapalli, Wenjun Lu, Gerhard Dehm, Dierk Raabe, and Zhiming Li, "Symbiotic crystal-glass alloys via dynamic chemical partitioning," Materials Today 51, 6-14 (2021).
Li, Z.; Ludwig, A.; Savan, A.; Springer, H.; Raabe, D.: Combinatorial metallurgical synthesis and processing of high-entropy alloys. Journal of Materials Research 33 (19), pp. 3156 - 3169 (2018)
Lu, W.; Liebscher, C.; Dehm, G.; Raabe, D.; Li, Z.: Bidirectional Transformation Enables Hierarchical Nanolaminate Dual‐Phase High‐Entropy Alloys. Advanced Materials 30 (44), 1804727 (2018)
Li, Z.; Körmann, F.; Grabowski, B.; Neugebauer, J.; Raabe, D.: Ab initio assisted design of quinary dual-phase high-entropy alloys with transformation-induced plasticity. Acta Materialia 136, pp. 262 - 270 (2017)
Li, Z.; Tasan, C. C.; Springer, H.; Gault, B.; Raabe, D.: Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys. Scientific Reports 7, 40704 (2017)
Li, Z.; Tasan, C. C.; Pradeep, K. G.; Raabe, D.: A TRIP-assisted dual-phase high-entropy alloy: Grain size and phase fraction effects on deformation behavior. Acta Materialia 131, pp. 323 - 335 (2017)
Luo, H.; Li, Z.; Raabe, D.: Hydrogen enhances strength and ductility of an equiatomic high-entropy alloy. Scientific Reports 7 (1), 9892 (2017)
Li, Z.; Raabe, D.: Strong and Ductile Non-equiatomic High-Entropy Alloys: Design, Processing, Microstructure, and Mechanical Properties. JOM-Journal of the Minerals Metals & Materials Society 69 (11), pp. 2099 - 2106 (2017)
Li, Z.; Pradeep, K. G.; Deng, Y.; Raabe, D.; Tasan, C. C.: Metastable high-entropy dual-phase alloys overcome the strength–ductility trade-off. Nature 534, pp. 227 - 230 (2016)
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