Phase transformation and microstructure evolution of the deformed Ti-30Zr-5Nb shape memory alloy

Journal Article · Sat Apr 15 00:00:00 EDT 2017 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2017.02.015· OSTI ID:22689737

Qu, Wentao ^[1]; Sun, Xuguang; Yuan, Bifei ^[1]; Xiong, Chengyang ^[2]; Li, Yan ^[2]; Nie, Yongsheng ^[3]

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1. School of Mechanical Engineering, Xi'an Shiyou University, Xi'an 710065 (China)
2. School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)
3. Lanzhou Seemine SMA Co. Ltd., Lanzhou 730010 (China)

The phase transformation and microstructures of the deformed Ti-30Zr-5Nb shape memory alloy were investigated. The X-ray diffraction measurements indicated that the Ti-30Zr-5Nb alloy was composed of a single orthorhombic α″-martensite phase. The alloy exhibited one yielding behavior in the tensile test, with a critical stress of ~ 600 MPa and a tensile strain of approximately 15%. A shape memory recovery accompanied by a permanent strain was exhibited in the deformed alloys when heated at 873 K. The permanent strain increased with increasing pre-strain. The microstructure evolution of the deformed alloy was investigated by transmission electron microscopy. The results showed that the martensite reorientation occurred and the dislocations were generated during deformation. The alloy displayed a reversible martensite transformation start temperature as high as 763 K. However, no strain-induced martensite stabilization was found in the deformed alloy with different pre-strain levels, potentially because the large chemical energy of the Ti-30Zr-5Nb alloy depressed the effects of the elastic energy and the dissipative energy. - Highlights: • Ti-30Zr-5Nb alloy is composed of single orthorhombic α″-martensite phase with M{sub s} of 721 K. • No martensite stabilization has been found in Ti-30Zr-5Nb alloy with different pre-strain. • Ti-30Zr-5Nb shows the maximum shape memory effect of 2.75% with a pre-strain of 8%.

• OSTI ID: 22689737
• Journal Information: Materials Characterization, Vol. 126; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DISLOCATIONS
MARTENSITE
MARTENSITIC STEELS
MICROSTRUCTURE
NIOBIUM ALLOYS
ORTHORHOMBIC LATTICES
PHASE TRANSFORMATIONS
SHAPE MEMORY EFFECT
STABILIZATION
STRAINS
TEMPERATURE RANGE 0400-1000 K
TITANIUM ALLOYS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
YIELDS
ZIRCONIUM ALLOYS