Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 15 No. 6 December 2005|
（Department of Materials Engineering, Dalian University of Technology,
Dalian 116024, China）
Abstract: Ti-50.6Ni(molar fraction, %) shape memory alloy solution treated at 850℃ for 1h followed by ageing treatment at 450℃ for 3h was studied with differential scanning calorimetry(DSC), X-ray diffractometry(XRD) and transmission electron microscopy(TEM). DSC measurement reveals two separate transformation peaks. XRD and TEM demonstrate that a three-stage transformation occurs. The Ti3Ni4 precipitates are coherent with the R-phase. The crystal structure of R-phase was analyzed by two diffraction patterns method. The diffraction patterns of R-phase were obtained in detail from the same region.
Key words: Ti-Ni shape memory alloys; R-phase transformation; Ti3Ni4 precipitates