TEM phase analysis of NiTi shape memory alloy prepared by self-propagating high-temperature synthesis

0470162 - FZÚ 2019 RIV GB eng J - Journal Article
Karlík, M. - Haušild, P. - Klementová, Mariana - Novák, P. - Beran, Přemysl - Perrière, L. - Kopeček, Jaromír
TEM phase analysis of NiTi shape memory alloy prepared by self-propagating high-temperature synthesis.
Advances in Materials and Processing Technologies. Roč. 3, č. 1 (2017), s. 58-69. ISSN 2374-068X
R&D Projects: GA ČR(CZ) GA14-03044S; GA MŠMT LO1603
EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510
Institutional support: RVO:68378271 ; RVO:61389005
Keywords : NiTi shape memory alloy, * neutron diffraction, * phase analysis, * light and electron microscopy
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)

The effect of annealing a Ni–48at.%Ti alloy prepared by selfpropagation high-temperature synthesis (SHS) by means of transmission electron microscopy (TEM) was studied. The alloy in the as-sintered condition shows the presence of B2 NiTi matrix, relatively large particles (2–100 μm) of cubic NiTi2 phase and very fine densely distributed particles of rhombohedral Ni4Ti3 phase. The phase fractions were determined by the Rietveld refinement of neutron diffraction. Twelve-hour annealing at 1000 °C leads to coarsening of Ni4Ti3 particles. Slow furnace cooling from the annealing temperature results in a transformation of the rhombohedral Ni4Ti3 phase to a metastable Ni3Ti2 phase with cubic symmetry. Its particles, coherent with the B2 matrix, have the form of thin oval platelets with lenticular cross-section.
Permanent Link: http://hdl.handle.net/11104/0295491