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IMMC

Antoine Hilhorst
PhD student
Ir. at UCL in 2017
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Main project: Fracture toughness of high entropy alloys
Funding: UCL Assistant
Supervisor(s): Pascal Jacques, Thomas Pardoen

High entropy alloys (HEAs) are a new family of metallic alloys. In contrast to conventional alloys, HEAs have multiple principal elements e.g. the equiatomic "Cantor" alloy CrMnFeCoNi. Alloys in this range of chemical composition have gathered attention only recently. From what was observed in conventional alloys, it was expected that HEAs microstructure be composed of several intermetallic phases but some systems are surprisingly single phase solid solution. Moreover, such single-phase alloys have excellent mechanical properties. For instance, CrMnFeCoNi possess a large fracture toughness, which increases with decreasing temperature, putting this alloy on par with the current best alloys used for cryogenic applications. As such, the objective of the thesis is to understand the underlying mechanisms responsible for the observed macroscopic behavior of such alloys.

The thesis aims to answer several questions such as: What are the mechanisms responsible for the increase in ductility, strength, and fracture toughness with decreasing temperature? What high-throughput methodology would be able to screen the vast range of possible chemical composition of HEAs for high performance alloys?

To understand the deformation mechanisms, several HEAs will be fully characterized from casting to mechanical testing. For the fracture toughness measurements, the essential work of fracture method will be employed as it is best suited for ductile thin sheets than compact tests. Diffusion multiples will be explored as a possible high-throughput method, as the presence of composition gradients allows the simultaneous characterization of a range of composition by techniques such as EDX, EBSD and nano-indentation.

IMMC main research direction(s):
Processing and characterisation of materials

Keywords:
fracture mechanics
metallurgy

Research group(s): IMAP

Recent publications

See complete list of publications

Conference Papers

1. Hilhorst, Antoine; Bille, Pierre; Favache, Audrey; Jacques, Pascal. High-throughput Experimental Design of High-Entropy Alloys. http://hdl.handle.net/2078.1/216294

2. Hilhorst, Antoine; Pardoen, Thomas; Jacques, Pascal. On the Characterization of the Exceptional Fracture Toughness of CrMnFeCoNi High Entropy Alloy. http://hdl.handle.net/2078.1/216292

3. Hilhorst, Antoine. High-Troughtput characterization method of non-equiatomic high entropy alloys. http://hdl.handle.net/2078.1/202927