Abstract
This experimental study focuses on the phase state and phase transformation response of the surface and subsurface of machined NiTi alloys. X-ray diffraction (XRD) analysis and differential scanning calorimeter techniques were utilized to measure the phase state and the transformation response of machined specimens, respectively. Specimens were machined under dry machining at ambient temperature, preheated conditions, and cryogenic cooling conditions at various cutting speeds. The findings from this research demonstrate that cryogenic machining substantially alters austenite finish temperature of martensitic NiTi alloy. Austenite finish (Af) temperature shows more than 25 percent increase resulting from cryogenic machining compared with austenite finish temperature of as-received NiTi. Dry and preheated conditions do not substantially alter austenite finish temperature. XRD analysis shows that distinctive transformation from martensite to austenite occurs during machining process in all three conditions. Complete transformation from martensite to austenite is observed in dry cutting at all selected cutting speeds.
| Original language | English |
|---|---|
| Pages (from-to) | 3597-3606 |
| Number of pages | 10 |
| Journal | Journal of Materials Engineering and Performance |
| Volume | 26 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 1 2017 |
Bibliographical note
Funding Information:Support from the NASA EPSCOR Program under Grant No. NNX11AQ31A and the NASA FAP Aeronautical Sciences Project are greatly acknowledged.
Publisher Copyright:
© 2017, ASM International.
Keywords
- DSC analysis
- NiTi shape memory alloy
- XRD analysis
- cryogenic machining
- surface integrity
ASJC Scopus subject areas
- Materials Science (all)
- Mechanics of Materials
- Mechanical Engineering