Stability of a Ni-rich Ni-Ti-Zr high temperature shape memory alloy upon low temperature aging and thermal cycling. (November 2016)

• Record Type: Journal Article
• Authors: Pérez-Sierra, A.M.; Pons, J.; Santamarta, R.; Karaman, I.; Noebe, R.D.
• Is Part Of: Scripta materialia. Volume 124(2016)
• Page Start: 47
• Page End: 50
• Publication Date: 2016-11
• Subjects: Martensitic phase transformations -- Shape memory alloys -- Precipitation -- Aging -- Phase instability; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2016.06.029
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The thermal stability of Ni50.3 Ti29.7 Zr20 with aging in austenite at 250 °C has been studied for three distinctive microstructures obtained after selected thermal treatments: precipitate free and containing two different sizes and densities of H-phase nanoprecipitates. The martensitic transformation is suppressed after 1–3 weeks aging, depending on the initial microstructure, due to a B2 phase instability in the form of short range atomic reordering within the Ti + Zr sublattice, considered to be precursor to the H-phase precipitation. Thermal cycling leads to notable changes in the transformation temperatures, which strongly depends on the starting microstructure. Graphical abstract: