Effect of Cu on Amorphization of a TiNi Alloy during HPT and Shape Memory Effect after Post‐Deformation Annealing. Issue 1 (5th July 2019)

• Record Type: Journal Article
• Authors: Shahmir, Hamed; Nili-Ahmadabadi, Mahmoud; Mohammadi, Mahdi; Huang, Yi; Andrzejczuk, Mariusz; Lewandowska, Małgorzata; Langdon, Terence G.
• Other Names: Kawasaki Megumi guestEditor.; Figueiredo Roberto B. guestEditor.; Zhilyaev Alexander P. guestEditor.
• Is Part Of: Advanced engineering materials. Volume 22:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-07-05
• Subjects: amorphization -- nanostructured materials -- severe plastic deformation -- shape memory effects -- TiNiCu alloys; Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.201900387
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : A ternary TiNiCu shape memory alloy is subjected to high‐pressure torsion (HPT) followed by post‐deformation annealing (PDA) to study the effect of Cu (5 at%) on amorphization after HPT processing and to investigate the microstructural evolution and shape memory effect (SME) after PDA. The results show that even after 20 revolutions the ternary alloy contains nanocrystalline areas and the microstructure is not fully amorphous. An easier martensite‐to‐austenite transformation and minor remaining austenite in the ternary alloy are responsible for suppressing amorphization. Post‐deformation annealing at 673 K provides nanocrystalline microstructures containing an R‐phase with a minor martensitic B19' phase in the ternary alloy. The SME of this alloy after PDA is not as satisfactory as that of the binary alloy processed through similar conditions because of the existence of a high volume fraction of the R‐phase. However, the total recovered strain of the ternary alloy after PDA for 30 min has a maximum value of 6.5%. Abstract : The present investigation is initiated to study the effect of Cu on amorphization of a TiNi alloy after high‐pressure torsion processing and to investigate the microstructural evolution and shape memory effect after post‐deformation annealing. Annealing at 673 K after severe plastic deformation provides nanocrystalline microstructures containing an R‐phase with a minor martensitic B19' phase, which represents the total recovered strain of 6.5%.