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Oxidation Behavior between 700 and 1300 °C of Refractory TiZrNbHfTa High‐Entropy Alloys Containing Aluminum
Author(s) -
Chang ChiaHsiu,
Titus Michael S.,
Yeh JienWei
Publication year - 2018
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201700948
Subject(s) - materials science , high entropy alloys , alloy , refractory (planetary science) , oxide , refractory metals , metallurgy , aluminium , oxygen , chemical engineering , chemistry , organic chemistry , engineering
Refractory alloys without Cr, Al, and Si additions exhibit very poor high temperature oxidation resistance and thus significantly limit their applications. With an aim to improve the poor oxidation resistance of strong and ductile refractory TiZrNbHfTa high‐entropy alloys (HEAs), this study investigates the effect of Al additions on the oxidation behavior and mechanisms for Al 0‐1 TiZrNbHfTa HEAs. Higher Al content renders the alloy more resistant to oxidation. The AlTiZrNbHfTa alloy exhibits a mass gain twice of that of conventional Ni‐based alloys at 1100 °C for 1 h, but much less than Nb refractory alloys because an Al‐containing oxide on the surface layer provides a partial barrier against oxidation between 700 and 1100 °C. But, at 1300 °C the Al‐containing alloys exhibit poor oxidation resistance because the less dense oxide layers provide oxygen with an effective diffusional channel and enable oxygen to penetrate the substrate more easily.