Tensile and plane bending fatigue properties of pure iron and iron-phosphorus alloys at room temperature in the air

2011 ◽  
Vol 64 (3) ◽  
pp. 315-320 ◽  
Author(s):  
M. A. Islam ◽  
N. Sato ◽  
Y. Tomota
2011 ◽  
Vol 674 ◽  
pp. 213-218 ◽  
Author(s):  
Hisaaki Tobushi ◽  
K. Kitamura ◽  
Yukiharu Yoshimi ◽  
K. Miyamoto ◽  
K. Mitsui

In order to develop a brain spatula or a brain retractor made of a shape memory alloy (SMA), the bending characteristics of the brain spatula of TiNi SMA made by the precision casting were discussed based on the tensile deformation properties of the existing copper and the TiNi rolled-SMA. The fatigue properties of both materials were also investigated by the plane-bending fatigue test. The results obtained can be summarized as follows. (1) The modulus of elasticity and the yield stress for the cast and rolled SMAs are lower than those for the copper. Therefore, the conventional rolled-SMA spatula and the new cast-SMA spatula can be bent easily compared to the existing copper-brain spatula. (2) With respect to the alternating- and pulsating-plane bending fatigue, the fatigue life of both the copper and the SMAs in the region of low-cycle fatigue is expressed by a power function of the maximum bending strain. The fatigue life of the conventional rolled SMA and the new cast SMA is longer than that of the existing copper. The fatigue life of the new cast and rolled SMAs in the pulsating-plane bending is longer than that in the alternating-plane bending. (3) The fatigue life of the rolled-SMA and the cast SMA for alternating- and pulsating-plane bendings can be expressed by the unified relationship with a power function of the dissipated work.


2016 ◽  
Vol 849 ◽  
pp. 347-352
Author(s):  
Xu Wang ◽  
Si Qing Li ◽  
Jing Nan Liu

The rotating bending fatigue properties of Ti65 titanium alloy blisk forging was studied in the present investigation. The smooth and notched specimens were prepared to test the fatigue properties at room temperature and 650°C. Meanwhile, the influences on rotating bending fatigue of temperature and type were analyzed. Furthermore, the fractural morphology was observed through scanning electron microscopy. The results showed that the medium fatigue strength of Ti65 titanium alloy decreased at 650°C compared with that at room temperature, and the fatigue strength of notched specimens indicated the same significant declination at different temperatures compared with smooth specimens. At room temperature the medium fatigue strength of smooth and notched are 473MPa and 173MPa, respectively, and the fatigue notch sensitive coefficient was 0.87. At 650°C the medium fatigue strength of smooth and notched specimens are 427MPa and 168MPa, where the fatigue notch sensitive coefficient was 0.78.


2011 ◽  
Vol 138-139 ◽  
pp. 832-835
Author(s):  
Yong Jie Liu ◽  
Qing Yuan Wang ◽  
Ren Hui Tian ◽  
Xiao Zhao

In this paper, tensile fatigue properties of 316L stainless steel thin sheets with a thickness of 0.1 mm are studied. The tests are implemented by using micro mechanical fatigue testing sysytem (MMT-250N) at room temperature under tension-tension cyclic loading. The S-N curve of the thin sheets descends continuously at low cycle region. Cyclic σ-N curve and ε-N curve are obtained according to the classical macroscopical fatigue theory. The results agree well with the experimental fatigue data, showing that the traditional fatigue research methods are also suitable for description of MEMS fatigue in a certain extent. The effect factor of frequency was considered in this study and the results show that the fatiuge life and the fatigue strength are increased as loading frequency increasing.


Author(s):  
Ming-Liang Zhu ◽  
Fu-Zhen Xuan ◽  
Zhengdong Wang

The fatigue properties of a low strength weld metal in a dissimilar welding joint in high cycle and very high cycle regimes were investigated by fully reversed axial tests in air at room temperature and 370°C. A clear duplex S-N curve existed as a result of the transition of fatigue failure mode from surface-induced failure to internal-induced failure at 370°C, while the S-N curve was continuously decreased at room temperature. A new model was successfully proposed to predict fatigue life, and interpret the crack initiation modes transition from surface inclusion to interior inclusion. It was concluded that cracks were initiated by competition among non-metallic inclusions, welding pores and discontinuous microstructures in high cycle regime. While in the very high cycle regime, non-metallic inclusions were the dominant crack initiation mechanism which depended on stress level, inclusion size as well as inclusion depth.


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