TY - JOUR
T1 - Quantitative three-dimensional analysis of Ni4Ti3 precipitate morphology and distribution in polycrystalline Ni-Ti
AU - Cao, S.
AU - Nishida, M.
AU - Schryvers, D.
N1 - Funding Information:
Part of this work was performed in the framework of a European FP6 Project “Multi-scale modeling and characterization for phase transformations in advanced materials” (MRTN-CT-2004-505226). Support was also provided by FWO Projects G.0465.05 “The functional properties of SMA: a fundamental approach”, G.0576.09 “3-D characterization of precipitates in Ni–Ti SMA by slice-and-view in a FIB–SEM dual-beam microscope”, “ Grant-in-Aid for Scientific Research ” (B -2036291 ) from JSPS and an FWO-JSPS Flemish–Japanese collaboration entitled “Advanced techniques for materials characterisation developed by an international cooperation between two centres of electron microscopy for materials research” (VS.007.09N).
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011/2
Y1 - 2011/2
N2 - The three-dimensional size, morphology and distribution of Ni 4Ti3 precipitates in a Ni50.8Ti49.2 polycrystalline shape memory alloy with a heterogeneous microstructure have been investigated using a focused ion beam/scanning electron microscopy slice-and-view procedure. The mean volume, central plane diameter, thickness, aspect ratio and sphericity of the precipitates in the grain interior as well as near to the grain boundary were measured and/or calculated. The morphology of the precipitates was quantified by determining the equivalent ellipsoids with the same moments of inertia and classified according to the Zingg scheme. Also, the pair distribution functions describing the three-dimensional distributions were obtained from the coordinates of the precipitate mass centres. Based on this new data it is suggested that the existence of the heterogeneous microstructure could be due to a very small concentration gradient in the grains of the homogenized material and that the resulting multistage martensitic transformation originates in strain effects related to the size of the precipitates and scale differences of the available B2 matrix in between the precipitates.
AB - The three-dimensional size, morphology and distribution of Ni 4Ti3 precipitates in a Ni50.8Ti49.2 polycrystalline shape memory alloy with a heterogeneous microstructure have been investigated using a focused ion beam/scanning electron microscopy slice-and-view procedure. The mean volume, central plane diameter, thickness, aspect ratio and sphericity of the precipitates in the grain interior as well as near to the grain boundary were measured and/or calculated. The morphology of the precipitates was quantified by determining the equivalent ellipsoids with the same moments of inertia and classified according to the Zingg scheme. Also, the pair distribution functions describing the three-dimensional distributions were obtained from the coordinates of the precipitate mass centres. Based on this new data it is suggested that the existence of the heterogeneous microstructure could be due to a very small concentration gradient in the grains of the homogenized material and that the resulting multistage martensitic transformation originates in strain effects related to the size of the precipitates and scale differences of the available B2 matrix in between the precipitates.
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U2 - 10.1016/j.actamat.2010.11.044
DO - 10.1016/j.actamat.2010.11.044
M3 - Article
AN - SCOPUS:78651406188
SN - 1359-6454
VL - 59
SP - 1780
EP - 1789
JO - Acta Materialia
JF - Acta Materialia
IS - 4
ER -