| Summary: | 碩士 === 義守大學 === 材料科學與工程學系 === 104 === In this study, high-entropy superalloy was selected as a base material for alloy design in order to develop low cost but high performance new type of heat-resistant
alloys. High-entropy superalloys (HESA-6/A/C) were nickel-based superalloys incorporated with high-entropy effect, wherein nickel (Ni) is a base element in HESAA
with eight different elements additions in which 2wt.% tantalum without niobium, on the other hand, 2wt% of niobium were added in HESA-C but no tantalum.
Specimens were prepared through directionally solidified casting processes and full solid solution and aging heat treatments, thereafter high temperature creep tests
(982C/159MPa) were conducted and high temperature oxidation tests (1000C 1hr/50hr/100hr) were investigated. Results show that the γ'' phase of high-entropy superalloy HESA-C is precipitated neatest and with maximum volume fraction, so as to the best high temperature creep behavior. After high temperature oxidation tests, the PFZ of HESA-C is the thinnest and a continuous dense oxide layer of Al2O3 is formed further to improve the oxidation resistance of the material, so that the oxidation behavior of HESA-C is the best among three high-entropy superalloys.
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