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
Bohan Wang, Li Cheng, Wenbin Cui, Xuan Chen, Changkai Wang, Dongchun Li
Summary: Ultrasonic fatigue tests were conducted on TC4 specimens with different microstructures, revealing varying crack initiation mechanisms. Additionally, it was found that axial tension influences the distribution of stress on the specimen cross section, leading to migration of the crack origin to the interior.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2021)
Article
Engineering, Mechanical
Yujia Liu, Bo Xu, Sen Tang, Lang Li, Chao He, Chong Wang, Qingyuan Wang
Summary: This paper presents a thermodynamic characterization method for estimating the internal crack growth rate in very high cycle fatigue research. It discusses a theoretical approach for surface temperature considering crack size, initiation site, and time for thin sheet material. Infrared thermography is used to study the inner crack behavior and heat dissipation phenomenon on high-strength stainless steel under 20 kHz vibration loading. A numerical simulation reveals the temperature elevation on surfaces caused by heat generation at the crack tip and heat conduction. Ultimately, the internal crack growth rate and final fatigue failure prediction are obtained by combining the calculation of heat dissipation and the observed evolution of the surface temperature field.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
Yi-Fan Yang, Hua-Yan Hu, Lin Min, Qian-Tao Sun, Miao Song, Ming-Liang Zhu, Jian-Feng Wen, Shan-Tung Tu
Summary: The HCF and VHCF behaviors and failure mechanism of Inconel 718 were investigated through ultrasonic fatigue tests and microscopic characterization techniques. It was found that the S-N curve continuously decreases in the HCF regime, while forming a plateau for VHCF. Cracks initiate from a single site on the surface or subsurface. Site-specific focused ion beam sampling and transmission electron microscopy characterization revealed that the crack initiation is governed by slip-induced localized plastic deformation. Microcracks initiate near non-metallic inclusions or slip band-grain boundary sites. Furthermore, a life correlation model considering the size of micro-defect was proposed to better correlate the fatigue life.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Review
Materials Science, Multidisciplinary
Peyman Shabani, Fathollah Taheri-Behrooz, Seyed Sina Samareh-Mousavi, Mahmood M. Shokrieh
Summary: This comprehensive review focuses on the high cycle and gigacycle fatigue of fiber-reinforced composite materials, categorizing different test methods and fatigue behavior, as well as presenting models for predicting fatigue behavior in VHC and GC regimes. The study also highlights the need for further investigation in certain areas to deepen understanding in the field.
PROGRESS IN MATERIALS SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
P. Zhao, Z. Xu, M. Wang, R. D. K. Misra, G. Xie, F. Du, L. Xia
Summary: The rail steel with multiphase structure processed by quenching and tempering heat treatment exhibited excellent high cycle fatigue behavior, with a fatigue limit as high as -790 MPa. The comparison with other high-strength steels suggested that the multiphase structure of steel has both good strength and high fatigue limit, indicating broad prospects in engineering applications.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Gen Li, Lei Ke, Xuechong Ren, Chengqi Sun
Summary: The fracture surface of TC17 alloy varies in morphology depending on the stress ratio, with facet characteristic at high stress ratio and rough area morphology at low stress ratio. Walker's equation is found to be more accurate than Goodman's equation and Smith-Watson-Topper's equation for predicting the effect of stress ratio on high cycle and very high cycle fatigue strength.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Nanoscience & Nanotechnology
Xiaolu Gui, Guhui Gao, Baifeng An, R. D. K. Misra, Bingzhe Bai
Summary: The study investigated the effects of inclusion size and microstructural features on HCF/VHCF in a B/M steel. It was found that fatigue crack initiation was mainly influenced by inclusions, with the majority of fatigue life consumed by the crack initiation process regardless of the source of the crack. The ratio of fatigue crack initiation life to total fatigue life exhibited a wide scatter due to variations in the B/M hierarchical structure within individual prior austenite grains when cracks initiated from sub-surface microstructure.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Stephanie Saalfeld, Marcel Krochmal, Thomas Wegener, Berthold Scholtes, Thomas Niendorf
Summary: VCHF tests on SAE 1045 steel under different deep rolled conditions revealed that the dominant failure mode is related to internal material defects causing fisheye fracture appearance. The stable tensile residual stresses in the core of high-temperature deep rolled specimens promoted crack initiation and advance, ultimately resulting in inferior fatigue strength.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Shawn L. Kiser, Marc Rebillat, Mikhail Guskov, Nicolas Ranc
Summary: Ultrasonic fatigue tests are used to study the fatigue life behavior of metallic components undergoing a high number of cycles under low mechanical loads. This paper introduces a spectral estimation method for extracting vibration signal parameters and recommends suitable algorithms for processing experimental data obtained from ultrasonic fatigue tests.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Engineering, Mechanical
Zhen Zhang, Zhenjie Teng, Jingyu Wang, Zhiyong Huang, Sebastian Muenstermann
Summary: The fatigue behavior of a Ni-based superalloy of grade GH4169 was investigated at room temperature and high temperature using ultrasonic and electromagnetic fatigue systems. The experiments revealed mixed-mode cracking at high temperature and pod-like structures at room temperature. Transmission electron microscopy investigations suggested that shear bands indicate the dominance of sliding movement in the microstructure variation of the high-temperature alloy.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Nanoscience & Nanotechnology
Alice Cervellon, Chris J. Torbet, Tresa M. Pollock
Summary: The anisotropic fatigue properties of three Ni-based SX superalloys were investigated in the very high cycle fatigue regime. The [111] orientation showed higher fatigue lives at high stresses but lower fatigue lives at very low stresses. The resolved shear stress on the octahedral slip systems and the pseudo-cube slip in the matrix were identified as the main reasons for the anisotropy effect.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Yury Matvienko, Vladimir Pisarev, Svyatoslav Eleonsky
Summary: An unconventional destructive method for quantitative assessment of fatigue damage accumulation in the stress concentration zone is proposed and verified. It is shown that normalized values of the notch mouth open displacement (NMOD), the stress intensity factor (SIF) and the T-stress can reliably be used as current damage parameter. The numerical integration of curves describing an evolution of fracture mechanics parameters produces the damage accumulation function in an explicit form.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Mechanics
Han Wu, Chengqi Sun, Wei Xu, Xin Chen, Xiaolei Wu
Summary: In this paper, a continuous runout method (CRM) is proposed to evaluate the fatigue strength in high cycle and very high cycle fatigue regimes based on the probability and statistics theory. The CRM features the simultaneous testing of multiple samples, which reduces the testing period to 1/5-1/3 of that by the common up-and-down method for 16 samples. Experimental data for G20Mn5QT steel, 40 Cr steel, and Ti-6Al-4V alloy validate the CRM's predicted lower limits of fatigue strength, which are slightly more conservative than those obtained by the up-and-down method.
ENGINEERING FRACTURE MECHANICS
(2023)
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.
