Effect of gaseous erosion on a decrease of the fatigue strength of specimens of titanium alloy VT8

1975 ◽  
Vol 7 (8) ◽  
pp. 1036-1037 ◽  
Author(s):  
V. M. Pleskach ◽  
P. A. Averchenko
Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2107
Author(s):  
Zhangjianing Cheng ◽  
Xiaojian Cao ◽  
Xiaoli Xu ◽  
Qiangru Shen ◽  
Tianchong Yu ◽  
...  

The effect of nano grain surface layer generated by ultrasonic impact on the fatigue behaviors of a titanium alloy Ti3Zr2Sn3Mo25Nb (TLM) was investigated. Three vibration strike-numbers of 24,000 times, 36,000 times and 48,000 times per unit are chosen to treat the surface of TLM specimens. Nanocrystals with an average size of 30 nm are generated. The dislocation motion plays an important role in the transformation of nanograins. Ultrasonic surface impact improves the mechanical properties of TLM, such as hardness, surface residual stress, tensile strength and fatigue strength. More vibration strike numbers will cause a higher enhancement. With a vibration strike number of 48,000 times per square millimeter the rotating-bending fatigue strength of TLM at 107 cycles is improved by 23.7%. All the fatigue cracks initiate from the surface of untreated specimens, while inner cracks appear after the fatigue life of 106 cycles with the ultrasonic surface impact. The crystal slip in the crack initiation zone is the main way of growth for microcracks. Crack cores are usually formed at the junction of crystals. The stress intensity factor of TLM titanium alloy is approximately 7.0 MPa·m1/2.


Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2892 ◽  
Author(s):  
Nils Wegner ◽  
Daniel Kotzem ◽  
Yvonne Wessarges ◽  
Nicole Emminghaus ◽  
Christian Hoff ◽  
...  

Laser powder bed fusion (L-PBF) of metals enables the manufacturing of highly complex geometries which opens new application fields in the medical sector, especially with regard to personalized implants. In comparison to conventional manufacturing techniques, L-PBF causes different microstructures, and thus, new challenges arise. The main objective of this work is to investigate the influence of different manufacturing parameters of the L-PBF process on the microstructure, process-induced porosity, as well as corrosion fatigue properties of the magnesium alloy WE43 and as a reference on the titanium alloy Ti-6Al-4V. In particular, the investigated magnesium alloy WE43 showed a strong process parameter dependence in terms of porosity (size and distribution), microstructure, corrosion rates, and corrosion fatigue properties. Cyclic tests with increased test duration caused an especially high decrease in fatigue strength for magnesium alloy WE43. It can be demonstrated that, due to high process-induced surface roughness, which supports locally intensified corrosion, multiple crack initiation sites are present, which is one of the main reasons for the drastic decrease in fatigue strength.


2006 ◽  
Vol 38 (6) ◽  
pp. 651-658 ◽  
Author(s):  
O. N. Gerasimchuk ◽  
G. A. Sergienko ◽  
V. I. Bondarchuk ◽  
A. V. Terukov ◽  
Yu. S. Nalimov ◽  
...  

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 811 ◽  
Author(s):  
Chengqi Sun ◽  
Qingyuan Song

Specimen geometry and loading condition usually have a great influence on the fatigue strength of metallic materials, which is an important issue in evaluating the reliability of component parts. In this paper, a rotating bending fatigue test is performed at first on an hourglass specimen and a notch specimen of a high strength titanium alloy. Experimental results indicate that, in terms of local stress, the notch specimen endures higher fatigue strength in comparison with the hourglass specimen due to its relatively smaller control volume. Then, a probabilistic control volume method is proposed for correlating the effects of specimen geometry and loading condition on the fatigue strength based on Weibull distribution and the concept of control volume. A simple formula is obtained for the fatigue strength in relation to control volumes, in which the parameter is the shape parameter of Weibull distribution of fatigue strength. The predicted results are in good agreement with the present experimental data for high strength titanium alloy and the data for the high strength steel and the full scale EA4T axle in the literature.


2016 ◽  
Vol 43 (7) ◽  
pp. 0702006
Author(s):  
李东霖 Li Donglin ◽  
何卫锋 He Weifeng ◽  
游熙 You Xi ◽  
张金 Zhang Jin ◽  
罗思海 Luo Sihai ◽  
...  

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