Effect of Al addition on mechanical properties and microstructure of refractory Al sub(x)HfNbTaTiZr alloys

This study developed a series of refractory Al sub(x)HfNbTaTiZr high-entropy alloys (HEAs) with an aim to improve strength, and reduce density of the very ductile base alloy HfNbTaTiZr. Despite the diversity of crystal structures among the constituent elements, all the HEAs are single solid solution...

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Bibliographic Details
Published in:Journal of alloys and compounds 2015-03, Vol.624, p.100-107
Main Authors: Lin, Chun-Ming, Juan, Chien-Chang, Chang, Chia-Hsiu, Tsai, Che-Wei, Yeh, Jien-Wei
Format: Article
Language:English
Subjects:
Alloys
Aluminum
Dendritic structure
Density
Fracture mechanics
Refractories
Solution strengthening
Strength
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Summary:This study developed a series of refractory Al sub(x)HfNbTaTiZr high-entropy alloys (HEAs) with an aim to improve strength, and reduce density of the very ductile base alloy HfNbTaTiZr. Despite the diversity of crystal structures among the constituent elements, all the HEAs are single solid solution phase with body-centered cubic (BCC) structure. The addition of Al significantly improves the strength but reduces the ductility due to large solution hardening. The linear relation between yield strength and atomic percentage of Al suggests that the strengthening effect of a certain element in a single-phase HEA alloy can be explained based on quasi-binary alloy concept. Crack formations in deformed AlHfNbTaTiZr alloy with the lowest fracture strain are mainly along the boundaries between dendrite and interdendrite. This agrees with its large deviation of Al content and thus strength between dendrite and interdendrite.
ISSN:0925-8388
DOI:10.1016/j.jallcom.2014.11.064