Effect of cold rolling ratio on the nanoscale precipitation behavior of TiNiPdCu based high temperature shape memory alloys

• Published in: Journal of alloys and compounds Vol. 599; pp. 212 - 218
• Main Authors: Khan, M. Imran, Kim, Hee Young, Khalid, F. Ahmad, Miyazaki, Shuichi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 25.06.2014; Elsevier
• Subjects: Alloys; Cold rolling; Cold rolling ratio; Cross-disciplinary physics: materials science; rheology; Deformation; Density; Exact sciences and technology; High temperature shape memory alloys; Martensitic transformations; Materials science; Nanoscale precipitates; Nanostructure; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Precipitates; Precipitation; Thermomechanical treatment; High temperature shape memory alloys; Cold rolling ratio; Nanoscale precipitates; Thermomechanical treatment; Annealing; Deformation ratio; Martensitic transformations; Heterogeneous nucleation; High temperature; Nanostructures; Defects; Cold rolling; Titanium alloys; Precipitation; Nano precipitate; Shape memory alloy; Thermomechanical treatments
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.02.067

•Prior cold deformation ratio plays an important role for the precipitation behavior.•Grain boundaries serve as the potential nucleation sites for TiPdCu precipitates.•Inclusions can also serve as the heterogeneous nucleation sites.•In annealed Ti-Ni-Pd-Cu alloys, the TiPdCu type precipitates are formed first.•The prior cold deformation can effectively improve shape memory properties. The effect of cold rolling ratio on precipitation behavior of an annealed Ti50Ni15Pd25Cu10 alloy was investigated. The change in the cold rolling ratio noticeably affected the precipitation behavior mainly due to the difference in the density of heterogeneous nucleation sites provided by the deformation induced defects. Higher cold rolling ratios caused an increase in the density of precipitates which subsequently caused a decrease in the martensitic transformation temperatures and shape recovery strain. It was confirmed that the prior cold deformation ratio is an important parameter to control the nanoscale precipitation behavior of Ti2Pd and TiPdCu type precipitates, both in terms of their overall density and distribution.