Fatigue behavior of pure titanium single crystals by bending method

Application of new materials, such as PMN-PT single crystals, requires a good understanding of basic material performance under both electrical and mechanical loading. Over the past 5 years the authors have used both computational and experimental techniques to examine the relationships between poling direction, crystal orientation, and electric field actuation. Experiments show mixed results indicating that the relationship between material orientation and loading is more complex than originally imagined. In some cases crack initiation and propagation perpendicular to the applied field was observed within a few thousand cycles but in other cases no failure was observed even after a few hundred thousand cycles despite crack growth in the presence of introduced defects. Computational effort quickly identified a gap between development of theoretical constitutive models that addressed domain switching based nonlinear behavior and what was available in workable form as part of commercial finite element codes. This led to the implementation of a macro-mechanical constitutive model which addresses domain switching, into a commercially available finite element code. The rate independent version has been used to investigate issues of electric field actuation and poling direction. Presented here are insights into the fracture and fatigue behavior of piezoelectric single crystals from both experimental and computational studies.

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The Role of Cross-Slip of Screw Dislocations in Fatigue Behavior of Copper Single Crystals

Basic Questions in Fatigue: Volume I ◽

10.1520/stp23207s ◽

2009 ◽

pp. 17-17-9 ◽

Cited By ~ 4

Author(s):

NY Jin ◽

AT Winter

Keyword(s):

Single Crystals ◽

Fatigue Behavior ◽

Cross Slip ◽

Screw Dislocations ◽

Copper Single Crystals

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Crack Orientation Dependence of Fatigue Behavior in Titanium Single Crystals by Thin Sheet Plain Bending

Experimental Mechanics in Nano and Biotechnology - Key Engineering Materials ◽

10.4028/0-87849-415-4.967 ◽

2006 ◽

pp. 967-970

Author(s):

Shinji Ando ◽

Takahiro Sakamoto ◽

Yukishige Ikejiri ◽

Masayuki Tsushida ◽

Hideki Tonda

Keyword(s):

Single Crystals ◽

Fatigue Behavior ◽

Thin Sheet ◽

Orientation Dependence ◽

Crack Orientation

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Fatigue behavior and magnetic property of Ni3(Al,Ti) single crystals deformed at high temperatures

Scripta Materialia ◽

10.1016/s1359-6462(00)00641-2 ◽

2001 ◽

Vol 44 (4) ◽

pp. 581-586 ◽

Cited By ~ 6

Author(s):

H.Y Yasuda ◽

A Sasaki ◽

Y Umakoshi ◽

S Takahashi

Keyword(s):

Magnetic Property ◽

Single Crystals ◽

High Temperatures ◽

Fatigue Behavior

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Crack Orientation Dependence for Fatigue Behavior of Titanium Single Crystals

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.345-346.351 ◽

2007 ◽

Vol 345-346 ◽

pp. 351-354 ◽

Cited By ~ 1

Author(s):

Takahiro Sakamoto ◽

Shinji Ando ◽

Hiromoto Kitahara ◽

Masayuki Tsushida ◽

Hideki Tonda

Keyword(s):

Single Crystals ◽

Fatigue Behavior ◽

Thin Sheet ◽

Orientation Dependence ◽

Test Method ◽

Prismatic Slip ◽

Bending Mode ◽

Bending Fatigue Test ◽

Fixed End ◽

Fatigue Fracture Behavior

In this present study, the fatigue behavior of titanium single crystals containing cracks growing in different crystallographic orientations has been investigated. To investigate fatigue fracture behavior of small single crystals, plain bending fatigue test method for thin sheet specimen was developed. One end of the sheet specimen is fixed at a voice coil of the loudspeaker and the other end is set free. A bending mode resonance occurs in the specimen due to forced vibration at the fixed end. In A-specimen, the notch plane and the direction are (11-20) and [1-100], respectively, the crack propagated parallel to {1-100} plane and striation-like markings were observed on the fatigue surfaces. In B-specimen with a notch of (1-100) and [11-20], the crack also propagated parallel to {1-100} plane as similar to A-specimen. These cracks are deduced to extend by alternating shear on two intersecting prismatic slip systems at the crack tip. In F-specimen with a notch of (0001) and [11-20], the crack propagated parallel to (0001) and twins were observed near the crack. As a result, S-N curves of each specimen showed strong orientation dependence and the fatigue strength of F-specimen was the highest in these specimens.

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