Effect of off-stoichiometric compositions on microstructures and phase transformation behavior in Ni-Cu-Pd-Ti-Zr-Hf high entropy shape memory alloys
نویسندگان
چکیده
Abstract High entropy shape memory alloys (HE-SMAs) show reversible martensitic phase transformations at elevated temperatures. HE-SMAs were derived from binary NiTi, to which the elements Cu, Pd, Zr and Hf are added. They represent ordered complex solid solutions. Their high temperature is of B2 type, where added occupy sites in Ni-(Cu, Pd) Ti-sub-lattices (Zr, Hf). In present study, advanced microstructural thermal characterization methods used study effects additional alloy on microstructures transformations. The ratios Ni-equivalent (Ni, Ti-equivalent (Ti, Zr, Hf) varied establish systems that correspond stoichiometric, under- over-stoichiometric alloys. It shown basic features cast heat-treated inherited nine X–Y subsystems (X: Ni, Pd; Y: Ti, transition temperatures characterize forward reverse depend concentrations all elements. data obtained demonstrate how martensite start affected by deviations composition an ideal stoichiometric phase. findings discussed light previous work concentration dependence SMA transformation temperatures, directions for development new compositions proposed.
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ژورنال
عنوان ژورنال: Journal of Alloys and Compounds
سال: 2021
ISSN: ['0925-8388', '1873-4669']
DOI: https://doi.org/10.1016/j.jallcom.2020.157467