Martensitic phase transformations in shape memory alloy: phase field modeling with surface tension effect

2016 ◽  
Vol 115 ◽  
pp. 137-144 ◽  
Author(s):  
Mahdi Javanbakht ◽  
Ehsan Barati
Keyword(s):  
Surface Tension ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Phase Transformations ◽  
Phase Field ◽  
Martensitic Phase ◽  
Phase Field Modeling ◽  
Surface Tension Effect ◽  
Field Modeling ◽  
Martensitic Phase Transformations

scholarly journals Structural refinement of neutron powder diffraction data of two-stage martensitic phase transformations in Ti50.75Ni47.75Fe1.50 shape memory alloy

2007 ◽  
Vol 22 (3) ◽  
pp. 209-218 ◽  
Author(s):  
Husin Sitepu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Phase Transformations ◽  
Powder Diffraction ◽  
Differential Scanning Calorimeter ◽  
Goodness Of Fit ◽  
Martensitic Phase ◽  
Structural Refinement ◽  
Two Stage ◽  
Martensitic Phase Transformations

Transformation behaviors of the technologically important polycrystalline Ti50.75Ni47.75Fe1.50 shape memory alloy were investigated using differential scanning calorimeter (DSC) and powder diffraction techniques. DSC revealed that there are two-stage (i.e., cubic→trigonal→monoclinic) martensitic phase transformations on cooling and a one-step transformation (monoclinic→cubic) on heating. In situ structural refinement of cubic→trigonal→monoclinic on cooling was carried out using the D1A high-resolution neutron powder diffractometer at the Institut Laue-Langevin Neutrons for Science in Grenoble, France. Results showed that the phases involved during the phase transition are consistent with the differential scanning calorimeter cooling curve, and the refined crystal structure parameters obtained from Rietveld refinements with the generalized spherical harmonic description agreed reasonably well with X-ray single-crystal data. Subsequently, a combined neutron and synchrotron structural refinement for each phase was conducted because the trial refinements initially using only the synchrotron data of trigonal phase yielded a false minimum with a somewhat high goodness-of-fit χ2. Results obtained from the combined neutron and synchrotron data of the cubic, trigonal, and monoclinic phases show that the same minimum goodness-of-fit indices were always obtained.

Sign in / Sign up

Export Citation Format

Share Document