Microstructural characterization of NiTi shape memory alloy produced by rotary hot forging. (29th May 2017)

• Record Type: Journal Article
• Authors: Rodrigues, P.; Braz Fernandes, F. M.; Paula, A. S.; Oliveira, J. P.; Ribeiro, S. B.; Texeira, E. N.; Schell, N.
• Is Part Of: Powder diffraction. Volume 32(2017)Supplement 1
• Page Start: S201
• Page End: S206
• Publication Date: 2017-05-29
• Subjects: rotary hot forging, -- X-ray diffraction, -- phase transformation, -- NiTi alloy, -- microstructural characterization; Powder metallurgy -- Periodicals; Materials -- Analysis -- Periodicals; 620.1127
• DOI: 10.1017/S0885715617000549
• Languages: English
• ISSNs: 0885-7156

Abstract

Abstract : The thermomechanical processing of NiTi shape memory alloys usually involves several steps of hot and/or cold deformation. The present work presents the structural characterization of a Ni-rich NiTi alloy bar, produced by vacuum-induced melting and thermomechanical processing in laboratory scale, aiming at massive production in the future. This study focused on the first step of hot working at 800 °C during rotary forging. Microstructural characterization was performed using differential scanning calorimetry, high- and low-temperature X-ray diffraction (XRD) using a laboratory source and synchrotron XRD. Thus, it was possible to obtain the phase transformation characteristics of the material: the transformation temperatures and the transformation sequence. Proposed thermomechanical processing is intended for production of bars and wires that will be subsequently drawn to get thin wires, for different applications, including orthodontic arch wires.