The effects of wide range of compositional changes on the martensitic transformation characteristics of NiTiHf shape memory alloys. (1st March 2019)

• Record Type: Journal Article
• Authors: Umale, Tejas; Salas, Daniel; Tomes, Bradley; Arroyave, Raymundo; Karaman, Ibrahim
• Is Part Of: Scripta materialia. Number 161(2019)
• Page Start: 78
• Page End: 83
• Publication Date: 2019-03-01
• Subjects: NiTiHf -- Martensitic phase transformation -- High temperature shape memory alloy -- Composition dependence; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2018.10.008
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The effects of composition on the martensitic transformation characteristics of NiTiHf shape memory alloys are systematically explored. Transformation temperatures (TTs) demonstrate a non-monotonic dependence on Ni and Hf concentrations. For Ni > 50 at%, TTs decrease with small Hf additions, attain a minimum or are completely suppressed, depending on Ni content, followed by a significant increase with Hf content. This initial drop in TTs becomes more pronounced with higher Ni contents and is attributed to the increase in nickel anti-site defects along with bulky substitutional Hf contributing to the increase in local lattice distortions along with the re-distribution of Ti and Hf. Graphical abstract: