An abnormal two-way shape memory effect in a rapidly solidified Ni51Ti49 alloy induced by low temperature constrained aging. (May 2018)

• Record Type: Journal Article
• Authors: Li, Y.Y.; Yao, X.Y.; Cao, S.; Ma, X.; Zeng, C.Y.; Zhang, X.P.
• Is Part Of: Scripta materialia. Number 149(2018)
• Page Start: 117
• Page End: 120
• Publication Date: 2018-05
• Subjects: NiTi alloy -- Two-way shape memory effect -- Constrained aging -- Stress field -- Ni4Ti3 precipitate; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2018.02.016
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: An abnormal two-way shape memory effect (TWSME) is found in a rapidly solidified Ni51 Ti49 alloy strip undergoing constrained aging treatment at relatively low temperatures (e.g., approximately below 385 °C for aging time of 1 h), which embodies the bending of the strip toward constrained position during martensitic transformation on cooling, showing stark difference from normal TWSME. The abnormal TWSME of the alloy is caused by weaker coherent stress field produced by ultrafine nano-sized Ni4 Ti3 precipitates than the residual stress field, whereas the latter dominates martensitic transformation and leads to bending with the direction opposite to that of normal TWSME. Graphical abstract: Unlabelled Image