Composition dependence of martensitic transformation and crystal structure in Ni50Mn25Ga25-xCux Heusler alloys. (June 2019)

• Record Type: Journal Article
• Authors: Brzoza, A.; Wierzbicka-Miernik, A.; Czeppe, T.; Cesari, E.; Szczerba, M.J.
• Is Part Of: Intermetallics. Volume 109(2019:Jun.)
• Page Start: 157
• Page End: 161
• Publication Date: 2019-06
• Subjects: A. shape-memory alloys -- B. alloy design -- C. heat treatment -- D. martensitic structure; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2019.03.019
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: A detailed analysis of the influence of Cu addition on the martensitic transformation and the composition dependent transitions in Ni50-x Mn25 Ga25 Cux Heusler alloys after two types of heat treatment was carried out. The chemical modification affected the martensitic transformation temperature, which increased from 202 to 691 K upon Cu addition. The chemical modification also affects the type of martensite structure, which changed from a ten-layered through a fourteen-layered and finally to a non-modulated crystal structure. At higher Cu content of ∼9 atomic percent precipitation of a second phase occurs enriched in Cu that disturbs the monotonic increase of the martensitic transformation temperature. It was also shown that water quenching at 1173 K affects the temperature and hysteresis of the martensitic transformation, as well as the chemical composition and temperature range of the 14 M → 2 M inter-martensitic transformation. Additionally, a narrow to wide transition of the martensitic transformation hysteresis was found to be independent of the applied heat treatments. Graphical abstract: Image 1 Highlights: Cu addition changes the martensitic transformation type in Ni50 Mn25 Ga25-x Cux alloys. Water quenching stabilizes the 14 M martensite phase in Ni50 Mn25 Ga25-x Cux alloys. Transition from a narrow to wide hysteresis of martensitic transformation occurs.