Article
Mechanics
R. G. Pettit, P. A. Wawrzynek, B. J. Carter, R. Singh, A. L. Pilchak, A. H. Rosenberger, M. Velez, T. W. Ward
Summary: The study introduces a new method for extracting a 3D anisotropic crack growth model from specific microstructural components in titanium alloys. By conducting fatigue crack growth tests and analyzing the results using novel techniques, the research confirms the potential of the method for evaluating local crack growth properties.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Chemistry, Physical
Tianle Li, Lixin Zhong, Huiping Wu, Dayong An, Xifeng Li, Jun Chen
Summary: The microstructure evolution and fatigue crack growth (FCG) behavior of diffusion bonded Ti-6Al-4V titanium alloy under synchronously changed temperature and pressure are systematically investigated. The study shows that outstanding FCG resistance and uncompromised tensile properties can be achieved by optimizing the process parameters.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Nanoscience & Nanotechnology
Abdul Khadar Syed, Xiang Zhang, Alec E. Davis, Jacob R. Kennedy, Filomeno Martina, Jialuo Ding, Stewart Williams, Philip B. Prangnell
Summary: The influence of three different deposition strategies on the fatigue crack growth behavior of WAAM Ti-6Al-4V was studied. The oscillation build exhibited the lowest crack growth rates and behaved more similarly to an annealed microstructure compared to the other two deposition strategies.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Mechanics
J. S. Jesus, L. P. Borrego, J. A. M. Ferreira, R. Branco, J. D. Costa, C. Capela
Summary: Mode I and mode I + II fatigue crack growth experiments were conducted using compaction tension shear specimens made of Ti-6Al-4V by additive manufacturing at various loading angles. The performance of different methodologies used to determine the equivalent stress intensity factor was studied. It was found that simpler methods achieved good results when considering the crack deflection angle in the algorithm. The crack growth speed was not significantly affected by the similar values of crack deflection angle, predominance of mode I loading, and similar crack closure effect.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Tao Gao, Xu Zhao, Hongqian Xue, Zhidan Sun
Summary: The fracture surface characteristics and micromechanisms of fish-eye crack initiation in a Ti-6Al-4V alloy under VHCF loading were investigated. The crack initiation area exhibited ragged-like mountains, dimples, and various irregular rods/particles, grooves, and microvoids. These characteristics were primarily attributed to the nucleation and coalescence of microvoids and grooves at the alpha(s)/beta(r) interface inside the beta(trans). The beta(trans) played a dominant role in the fish-eye crack initiation and early propagation process.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Engineering, Mechanical
Fumiyoshi Yoshinaka, Gaoge Xue, Nao Fujimura, Takashi Nakamura
Summary: The study on small crack propagation tests conducted on Ti-6Al-4V specimens under varying vacuum pressures showed that crack initiation life increased and crack propagation rate decreased with decreasing vacuum pressure. Fractographic features varied, with angular surfaces in air and under 10(0) Pa, and granular features below 10(-2) Pa. The window periods formed an oxidized surface coverage which influenced the crack propagation rate and fracture surface features. Surface cracks under 10(-4)-10(-6) Pa exhibited characteristics similar to internal cracks, suggesting a high vacuum environment around the internal cracks.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Nanoscience & Nanotechnology
Yongming Ren, Xin Lin, Zengyun Jian, Haoran Peng, Weidong Huang
Summary: The study investigated the fatigue crack growth behavior of Ti-6Al-4V alloy fabricated by high-power laser directed energy deposition, revealing parts under heat treated conditions exhibit superior FCG resistance. The research also calculated the plastic zone sizes ahead of the crack tip and proposed a method to determine the typical microstructural characteristic of additive manufactured Ti-6Al-4V parts.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Fumiyoshi Yoshinaka, Takashi Nakamura, Hiroyuki Oguma, Nao Fujimura, Akihisa Takeuchi, Masayuki Uesugi, Kentaro Uesugi
Summary: The initiation of internal fatigue cracks in very high cycle fatigue of Ti-6Al-4V alloy was investigated using synchrotron radiation X-ray computed tomography (SR-CT). Micro-CT detected 28 cracks that were distributed across the examined volume of CYRILLIC CAPITAL LETTER EF1.8 x L 2.5 mm. No apparent correlation was observed between the spatial distribution, initial lengths, and initiation lives of cracks. The crack growth rate of the facet-sized crack varied widely; some cracks propagated rapidly, whereas no crack growth was observed for other cracks over a specific period of time after detection. Using nano-CT, the several grain-sized internal cracks and their microstructures were clearly and nondestructively visualized. In the field of view, many primary alpha phases were detected; however, no other cracks were observed. The multiple facet initiation site, which is commonly observed for titanium alloys, might not be due to the concurrently initiated facets but may be caused by the small crack growth accompanied by facet formation.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Chemistry, Physical
Rhys Jones, Calvin Rans, Athanasios P. Iliopoulos, John G. Michopoulos, Nam Phan, Daren Peng
Summary: The study examines the variability in crack growth in AM Ti-6Al-4V specimens and highlights the ability of the Hartman-Schijve crack growth equation to capture this variability and anisotropic behavior. Despite the large variability in crack growth, the intrinsic crack growth equation remains unchanged, with changes in both the fatigue threshold and cyclic fracture toughness accounting for the variability and anisotropy observed in the test program.
Article
Chemistry, Physical
Junqiang Ren, Qi Wang, Binbin Zhang, Dan Yang, Xuefeng Lu, Xiaobo Zhang, Xudong Zhang, Jingyu Hu
Summary: The study found that the microstructure (bimodal and lamellar structure) of the Ti-6Al-3Nb-2Zr-1Mo alloy has an impact on the fatigue crack growth rate, with the lamellar structure exhibiting slower crack growth rate and more tortuous paths. The frequency of crack deflection and bifurcation is higher in lamellar structure compared to bimodal structure.
Article
Nanoscience & Nanotechnology
Hang Lv, Zhenlin Zhang, Yarong Chen, Yan Liu, Hui Chen, Yong Chen, Jing Cheng, Jian She, Huabing He, Jintao Chen
Summary: In this study, several large Ti-6Al-4V blocks were fabricated successfully using high-power laser metal deposition (HP-LMD). The high cycle fatigue (HCF) property and fatigue crack growth (FCG) behavior of the as-built Ti-6Al-4V alloy were investigated in horizontal and vertical directions. The results showed that the HCF performance of the vertical specimens was superior to the horizontal specimens, but inferior to the wrought Ti-6Al-4V. Additionally, the fatigue crack growth rate of the vertical specimens was lower than that of the horizontal specimens.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Jinta Arakawa, Hiroki Sato, Ryosuke Handa, Yukihiko Kimura, Shotaro Hashimoto, Hiroyuki Akebono, Atsushi Sugeta
Summary: A plane bending fatigue test was conducted on Ti-6Al-4V to identify the crystal grains and slip system responsible for fatigue crack initiation. The study found that fatigue cracks were caused by basal slip. The results showed that the number of crystal grains where fatigue crack may initiate can be limited by considering the grain size and the out-of-plane component of the Schmid factor.
MATERIALS SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Keke Tang, Kunrong Chen, Paolo Ferro, Filippo Berto
Summary: The effects of lamellar microstructure and microdefects on the fatigue performance of bimodal Ti-6Al-4V have been studied in this paper. A new intragrain weight integration approach was proposed to consider intragranular accumulative deformation, and a parametric accumulative difference indicator was defined to quantify the lamellar microstructural effect. The results have significant implications for the material design and manufacturing of advanced metal alloys.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Nanoscience & Nanotechnology
Yong Xie, Mengcheng Gong, Qingjun Zhou, Quan Li, Fude Wang, Xiaoyan Zeng, Ming Gao
Summary: This study investigates the effect of microstructure on fatigue crack growth (FCG) behavior in WAAM Ti-6Al-4V material. It was found that Delta KT plays a significant role in influencing the FCGR. Samples with different grain boundary alpha structures exhibit different FCG behaviors, with continuous alpha GB structures showing anisotropy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Tao Gao, Hongqian Xue, Zhidan Sun
Summary: The VHCF properties and damage mechanisms of a Ti-6Al-4V alloy with needle-like beta phase were investigated, revealing that fatigue damage is primarily caused by interior crack initiation with a fish-eye pattern. The formation of this particular appearance is attributed to the nucleation and coalescence of microvoids and grooves occurring in the transformed beta phase (beta(t)), which plays a dominant role in the crack initiation process of Ti-6Al-4V in the VHCF regime.