Loading...

High temperature deformation and processing map of a NiTi intermetallic alloy

Morakabati, M ; Sharif University of Technology | 2011

1129 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.intermet.2011.05.005
  3. Publisher: 2011
  4. Abstract:
  5. The deformation behavior of a 49.8 Ni-50.2 Ti (at pct) alloy was investigated using the hot compression test in the temperature range of 700 °C-1100 °C, and strain rate of 0.001 s-1 to 1 s-1. The hot tensile test of the alloy was also considered to assist explaining the related deformation mechanism within the same temperature range and the strain rate of 0.1 s-1. The processing map of the alloy was developed to evaluate the efficiency of hot deformation and to identify the instability regions of the flow. The peak efficiency of 24-28% was achieved at temperature range of 900 °C-1000 °C, and strain rates higher than 0.01 s -1 in the processing map. The hot ductility and the deformation efficiency of the alloy exhibit almost similar variation with temperature, showing maximum at temperature range of 900 °C-1000 °C and minimum at 700 °C and 1100 °C. Besides, the minimum hot ductility lies in the instability regions of the processing map. The peak efficiency of 28% and microstructural analysis suggests that dynamic recovery (DRV) can occur during hot working of the alloy. At strain rates higher than 0.1 s-1, the peak efficiency domain shifts from the temperature range of 850 °C-1000 °C to lower temperature range of 800 °C-950 °C which is desirable for hot working of the NiTi alloy. The regions of flow instability have been observed at high Z values and at low temperature of 700 °C and low strain rate of 0.001 s-1. Further instability region has been found at temperature of 1000 °C and strain rates higher than 1 s-1 and at temperature of 1100 °C and all range of strain rates
  6. Keywords:
  7. B. Deformation map ; C. Thermomechanical treatment ; A. Intermetallics ; Deformation behavior ; Deformation efficiency ; Deformation mechanism ; Dynamic recovery ; Flow instabilities ; High temperature deformation ; Hot compression tests ; Hot-tensile tests ; Intermetallic alloys ; Low strain rates ; Low temperatures ; Microstructural analysis ; NiTi alloys ; Peak efficiency ; Processing maps ; Temperature range ; Thermo-mechanical ; Z value ; Cerium alloys ; Compression testing ; Deformation ; Ductility ; Efficiency ; Hot working ; Intermetallics ; Stability ; Tensile testing ; Thermomechanical treatment ; Titanium alloys ; Strain rate
  8. Source: Intermetallics ; Volume 19, Issue 10 , October , 2011 , Pages 1399-1404 ; 09669795 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0966979511001385