Stability of a Ni-rich Ni-Ti-Zr high temperature shape memory alloy upon low temperature aging and thermal cycling

SCRIPTA MATERIALIA

卷:124

Article

Perez-Sierra, A. M.¹  Pons, J.¹  Santamarta, R.¹  Karaman, I.²  Noebe, R. D.³ 

[1] Univ Illes Balears, Dept Fis, Ctra Valldemossa,Km 7-5, E-07122 Palma De Mallorca, Spain

[2] Texas A&M Univ, Dept Mat Sci & Engn, College Stn, TX 77843 USA

[3] NASA, Struct & Mat Div, Glenn Res Ctr, Cleveland, OH 44135 USA

关键词: Martensitic phase transformations;    Shape memory alloys;    Precipitation;    Aging;    Phase instability;   

DOI  :  10.1016/j.scriptamat.2016.06.029

来源: Elsevier

【 摘 要 】

The thermal stability of Ni50.3Ti29.7Zr20 with aging in austenite at 250 degrees 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. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

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