Effect of crystallographic compatibility and grain size on the functional fatigue of sputtered TiNiCuCo thin films

被引：40

作者：

Chluba, C. ^{[1
]}

Ge, W. ^{[2
]}

Dankwort, T. ^{[1
]}

Bechtold, C. ^{[3
]}

de Miranda, R. Lima ^{[3
]}

Kienle, L. ^{[1
]}

Wuttig, M. ^{[2
]}

Quandt, E. ^{[1
]}

机构：

[1] Univ Kiel, Inst Mat Sci, Fac Engn, Kiel, Germany

[2] Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20742 USA

[3] Acquandas GmbH, Kiel, Germany

来源：

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES | 2016年 / 374卷 / 2074期

基金：

美国国家科学基金会;

关键词：

NiTi; shape memory alloys; fatigue; thin films; superelasticity; SHAPE-MEMORY ALLOYS; MARTENSITIC PHASE-TRANSFORMATIONS; PLASTIC-DEFORMATION; MECHANICAL-BEHAVIOR; CYCLIC DEFORMATION; NITI ALLOYS; MICROSTRUCTURE; HYSTERESIS; STABILITY; EVOLUTION;

D O I：

10.1098/rsta.2015.0311

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

The positive influence of crystallographic compatibility on the thermal transformation stability has been already investigated extensively in the literature. However, its influence on the stability of the shape memory effect or superelasticity used in actual applications is still unresolved. In this investigation sputtered films of a highly compatible TiNiCuCo composition with a transformation matrix middle eigenvalue of 1 +/- 0.01 are exposed to thermal as well as to superelastic cycling. In agreement with previous results the thermal transformation of this alloy is with a temperature shift of less than 0.1K for 40 cycles very stable; on the other hand, superelastic degradation behaviour was found to depend strongly on heat treatment parameters. To reveal the transformation dissimilarities between the differently heat-treated samples, the microstructure has been analysed by transmission electron microscopy, in situ stress polarization microscopy and synchrotron analysis. It is found that good crystallographic stability is not a sufficient criterion to avoid defect generation which guarantees high superelastic stability. For the investigated alloy, a small grain size was identified as the determining factor which increases the yield strength of the composition and decreases the functional degradation during superelastic cycling. This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

引用

页数：14

共 38 条

[21] In situ observation of stress-induced martensitic transformation and plastic deformation in TiNi alloy [J].