Grain Nucleation and Growth in Deformed NiTi Shape Memory Alloys: An In Situ TEM Study

被引：10

作者：

Burow J. ^{[1
]}

Frenzel J. ^{[1
]}

Somsen C. ^{[1
]}

Prokofiev E. ^{[2
]}

Valiev R. ^{[2
,3
]}

Eggeler G. ^{[1
]}

机构：

[1] Institute for Materials, Ruhr University Bochum, Universitätsstr. 150, Bochum

[2] Saint Petersburg State University, 7/9 Universitetskaya nab, St. Petersburg

[3] Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marx Street, Ufa

来源：

Shape Memory and Superelasticity | 2017年 / 3卷 / 04期

关键词：

Crystallization; Grain growth; NiTi shape memory alloys (SMAs); Recrystallization; Severe plastic deformation; Transmission electron microscopy;

D O I：

10.1007/s40830-017-0119-y

中图分类号：

学科分类号：

摘要：

The present study investigates the evolution of nanocrystalline (NC) and ultrafine-grained (UFG) microstructures in plastically deformed NiTi. Two deformed NiTi alloys were subjected to in situ annealing in a transmission electron microscope (TEM) at 400 and 550 °C: an amorphous material state produced by high-pressure torsion (HPT) and a mostly martensitic partly amorphous alloy produced by wire drawing. In situ annealing experiments were performed to characterize the microstructural evolution from the initial nonequilibrium states toward energetically more favorable microstructures. In general, the formation and evolution of nanocrystalline microstructures are governed by the nucleation of new grains and their subsequent growth. Austenite nuclei which form in HPT and wire-drawn microstructures have sizes close to 10 nm. Grain coarsening occurs in a sporadic, nonuniform manner and depends on the physical and chemical features of the local environment. The mobility of grain boundaries in NiTi is governed by the local interaction of each grain with its microstructural environment. Nanograin growth in thin TEM foils seems to follow similar kinetic laws to those in bulk microstructures. The present study demonstrates the strength of in situ TEM analysis and also highlights aspects which need to be considered when interpreting the results. © 2017, ASM International.

引用

页码：347 / 360

页数：13

共 78 条

[1]

Otsuka K., Waymann C.M., Shape memory materials, (1998)

[2]

Funakubo H., Shape memory alloys, (1987)

[3]

Lagoudas D.C., Shape memory alloys: modeling and engineering applications, (2008)

[4]

Otsuka K., Ren X., Physical metallurgy of Ti-Ni-based shape memory alloys, Prog Mater Sci, 50, 5, pp. 511-678, (2005)

[5]

Rahim M., Frenzel J., Frotscher M., Pfetzing-Micklich J., Steegmuller R., Wohlschlogel M., Mughrabi H., Eggeler G., Impurity levels and fatigue lives of pseudoelastic NiTi shape memory alloys, Acta Mater, 61, 10, pp. 3667-3686, (2013)

[6]

Eggeler G., Hornbogen E., Yawny A., Heckmann A., Wagner M., Structural and functional fatigue of NiTi shape memory alloys, Mater Sci Eng A, 378, 1-2, pp. 24-33, (2004)

[7]

Robertson S.W., Pelton A.R., Ritchie R.O., Mechanical fatigue and fracture of Nitinol, Int Mater Rev, 57, 1, pp. 1-36, (2012)

[8]

Robertson S.W., Launey M., Shelley O., Ong I., Vien L., Senthilnathan K., Saffari P., Schlegel S., Pelton A.R., A statistical approach to understand the role of inclusions on the fatigue resistance of superelastic Nitinol wire and tubing, J Mech Behav Biomed, 51, pp. 119-131, (2015)

[9]

Miyazaki S., Igo Y., Otsuka K., Effect of thermal cycling on the transformation temperatures of Ti-Ni alloys, Acta Metall Mater, 34, 10, pp. 2045-2051, (1986)

[10]

Miyazaki S., Thermal and stress cycling effects and fatigue properties of Ni-Ti alloys, Engineering aspects of shape memory alloys, (1990)

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