Effect of Annealing on the Mechanical and Thermomechanical Characteristics of a Ti50Pd40Ni10 Alloy with High-Temperature Shape Memory Effect Studied on a Strip

• Published in: Russian metallurgy Metally 2021-07, Vol.2021 (7), p.830-841
• Main Authors: Popov, N. N., Presnyakov, D. V., Lar’kin, V. F., Grishin, E. N., Kostyleva, A. A.
• Format: Article
• Language: English
• Subjects: Annealing; Chemistry and Materials Science; Grain size; Heat resistant alloys; Heating; High temperature; Martensitic transformations; Materials Science; Metallic Materials; Microhardness; Safety devices; Shape effects; Shape memory alloys; Strip; Temperature; Tensile strain; Thermomechanical properties; Transformation temperature; Vacuum annealing
• ISSN: 0036-0295; 1555-6255; 1531-8648
• DOI: 10.1134/S0036029521070089

The properties of a Ti 50 Pd 40 Ni 10 alloy (at %) with a high-temperature shape memory effect (SME) are studied on samples manufactured from a 2.04-mm-thick strip after various annealing and strain-creation conditions. Data on the elemental and local phase compositions, the grain sizes and the microhardness, the phase transformation temperatures, and the mechanical and thermomechanical characteristics have been obtained. The best average shape memory characteristics (ε SME = 4.3%, η SME = 0.57) are found to be obtained for the alloy samples subjected to vacuum annealing (600°C, 1 h) on heating to 500°C (stable end of SME) after the tensile strain preliminarily induced at a temperature of 380–370°C (after heating to 450°C) at a rate ≈ 3.1 × 10 –3 s –1 and the same degree of total induced strain ε t = 11%. In this case, the average temperatures of the start and finish of the main shape recovery are A s SME = 418°C and A f SME = 435°C, respectively. These thermomechanical characteristics are acceptable for an alloy chosen for creation of safety devices, e.g., of a cutting type, in which thermosensitive elements have a tray shape.