Evolution of elastic constants of the NiTi shape memory alloy during a stress-induced martensitic transformation. (15th April 2021)

• Record Type: Journal Article
• Authors: Grabec, Tomáš; Sedlák, Petr; Zoubková, Kristýna; Ševčík, Martin; Janovská, Michaela; Stoklasová, Pavla; Seiner, Hanuš
• Is Part Of: Acta materialia. Volume 208(2021)
• Publication Date: 2021-04-15
• Subjects: NiTi -- Shape memory alloy (SMA) -- In situ tension test -- Ultrasonic characterization -- Anisotropic elasticity; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.116718
• Languages: English
• ISSNs: 1359-6454

Abstract

Graphical abstract: Abstract: We carried out an in situ ultrasonic characterization of a NiTi shape memory alloy polycrystal subjected to pseudoplastic straining. The measurement leads to a full elastic tensor of the transversely isotropic polycrystal during the stress-induced austenite → R-phase → B19 ′ martensite transformation. The results reveal a strong anisotropy of the R-phase already in the low-strain state, which is then retained in character throughout the R-phase → martensite transition and even in the stress-free oriented martensite after the unloading. By using a micromechanical model based on homogenization approaches, we show that this strong anisotropy is probably related to twin boundaries both in the R-phase and in martensite rather than to the anisotropy of the unit cell and the crystallographic texture.