This article presents a review on recent advances in the fatigue behavior of Ti alloys, especially the main commercial compositions for orthopedic applications. In the case of well-known Ti–6Al–4V alloy, the major concern is related to the effect of the surface modification necessary to improve the osseointegration. The introduction of surface discontinuities due to the growth of a porous oxide layer, or the roughness development, may severely affect the fatigue performance depending on the level of alteration. In the case of additive manufactured Ti–6Al–4V, the fatigue response is also influenced by inherent defects of as-built parts. Regarding the recently developed metastable β alloys, information about the fatigue properties is still scarce and mainly related to the effect of second phase precipitates, which are introduced to optimize the mechanical properties. The fatigue behavior of the Ti alloys is complex, as is their microstructure, and should not be neglected when the alloys are being developed or improved to be applied in medical devices.

Grain refinement has been applied to enhance the materials strength for miniaturization and lightweight design of nuclear equipment. It is critically important to investigate the low-cycle fatigue (LCF) properties of grain refined 316LN austenitic stainless steels for structural design and safety assessment. In the present work, a series of fine-grained (FG) 316LN steels were produced by thermo-mechanical processes. The LCF properties were studied under a fully reversed strain-controlled mode at room temperature. Results show that FG 316LN steels demonstrate good balance of high strength and high ductility. However, a slight loss of ductility in FG 316LN steel induces a significant deterioration of LCF life. The rapid energy dissipation in FG 316LN steels leads to the reduction of their LCF life. Dislocations develop rapidly in the first stage of cycles, which induces the initial cyclic hardening. The dislocations rearrange to form dislocations cell structure resulting in cyclic softening in the subsequent cyclic deformation. Strain-induced martensite transformation appears in FG 316LN stainless steels at high strain amplitude (Δε/2 = 0.8%), which leads to the secondary cyclic hardening. Moreover, a modified LCF life prediction model for grain refined metals predicts the LCF life of FG 316LN steels well.

The thickness effect has a significant influence on the fatigue life of micro–nanometer thin films. Due to the increasing application of micro–nanometer thin films in the field of microelectronics, a suitable fatigue prediction model is urgently needed. To reveal the impact of the thickness effect on the fatigue life of a copper wire film, cyclic tension fatigue test of four groups of copper wire films were carried out. Based on the theory of continuous damage mechanics and damage homogenization method, a fatigue damage accumulation model that considered the film thickness was proposed. Based on the proposed fatigue damage prediction model, the damage evolution law and fatigue life of copper wire films with different thickness and strain range were predicted. Furthermore, the size effect of the copper films was analyzed. The results showed that the fatigue life of copper wire films will decrease with the increase of thickness and strain amplitude; the thinner the film, the more significant the thickness effect on the fatigue life is; with the increase of the film thickness, the film thickness effect will gradually decrease.

The World Cancer Research Fund and American Institute for Cancer Research (WCRF/AICR) advise cancer survivors to follow their lifestyle recommendations for cancer prevention. Adhering to these recommendations may have beneficial effects on patient-reported outcomes after a cancer diagnosis, but evidence is scarce. We aimed to assess associations of the individual dietary WCRF/AICR recommendations regarding fruit and vegetables, fibre, fast foods, red and processed meat, sugar-sweetened drinks and alcohol consumption with patient-reported outcomes in colorectal cancer (CRC) survivors. Cross-sectional data of 150 stage I–III CRC survivors, 2–10 years post-diagnosis, were used. Dietary intake was measured by 7-d dietary records. Validated questionnaires were used to measure health-related quality of life (HRQoL), fatigue and neuropathy. Confounder-adjusted linear regression models were used to analyse associations of each WCRF/AICR dietary recommendation with patient-reported outcomes. Higher vegetable intake (per 50 g) was associated with better global QoL (β 2·6; 95 % CI 0·6, 4·7), better physical functioning (3·3; 1·2, 5·5) and lower levels of fatigue (−4·5; −7·6, −1·4). Higher fruit and vegetables intake (per 100 g) was associated with better physical functioning (3·2; 0·8, 5·5) and higher intake of energy-dense food (per 100 kJ/100 g) with worse physical functioning (−4·2; −7·1, −1·2). No associations of dietary recommendations with neuropathy were found. These findings suggest that adhering to specific dietary WCRF/AICR recommendations is associated with better HRQoL and less fatigue in CRC survivors. Although the recommendations regarding healthy dietary habits may be beneficial for the well-being of CRC survivors, longitudinal research is warranted to gain insight into the direction of associations.

A detailed electron backscatter diffraction (EBSD) characterization was utilized to investigate abnormal grain growth behavior of nanocrystalline (NC) Au films constrained by a flexible substrate under cyclic loading. Abnormally grown grains (AGGs) in front of about 15 fatigue cracks were picked out to investigate the grain reorientation behavior during abnormal grain growth in the fatigue crack tip in the cyclically deformed thin films. It shows that the AGGs exhibited 〈001〉 orientation along the loading direction, whereas grains grown far away from fatigue cracks had no significant texture change. The cyclic cumulative shear strain was found to play a key role in grain reorientation. A lattice rotation model was proposed to elucidate the grain reorientation mechanism during abnormal grain growth. Such grain reorientation behavior of NC metals was found to provide an intrinsic resistance of the NC metals to fatigue damage.

Secrecy involves the active concealment of information from others, which can cause undesirable consequences for cognitive, perceptual and health psychology, but empirical research linking secrecy to charitable behaviors remains relatively scarce. This research examined whether secrecy weakens people’s desire to engage in charitable behaviors. Two experiments demonstrated that as a mental burden, secrets decreased people’s donation desire, including their intentions to volunteer and donate, and their tangible charitable behavior. In Experiment 1, recalling a personal secret increased the tendency to donate less money than recalling a neutral experience. Study 2 showed that this weakening effect of secrecy on charitable behaviors is mediated by fatigue (but not negative affect).

The fatigue behavior of a low-cost Zr52.1Ti5Cu17.9Ni14.6Al10Y0.4 (at%) (ZrCuNi-based) bulk-metallic glass (BMG) prepared by industrial-grade material was investigated under three-point bending loading modes. In order to obtain the fatigue stress-life (S-N) data, stress-controlled experiments were conducted using a computer-controlled material test system electrohydraulic testing machine at 60 Hz with a 0.1 R ratio in the air at room temperature. The fatigue limit (~174 MPa) in stress amplitude and fatigue ratio (~0.14) of this BMG is comparative to the similar BMG (Vit-105) prepared by high pure raw materials. The crack initiated from inclusions near the rectangular corners at the outer surface of the rectangular beam due to stress concentration. The striations and vein-like patterns were observed in the crack propagation region and fast fracture region, respectively.

Aircraft full-scale fatigue tests are expensive and time-consuming to conduct but are a critical item on the certification path of any aircraft design or modification. This paper outlines a proposal that trades cycling hours for increased detail in the teardown of a metallic test article. A method for determining the equivalent demonstrated crack size (and crack growth curve) at the mandated test life utilising the lead crack framework is demonstrated. It is considered that the test duration can be significantly reduced, whilst still achieving all the desired outcomes of a certification program.

In the scope of this work, a micromechanical model based on the crystal plasticity finite element method is proposed and applied to describe the nucleation and growth of microstructurally short fatigue cracks in polycrystalline materials under cyclic loads. The microstructure is generated in the form of a representative volume element of a polycrystalline material with equiaxed grains having columnar structure along thickness and random crystallographic texture. With this model, we investigate the influence of loading amplitude on the crack growth behavior. It is shown that for smaller strain amplitudes, a single crack nucleates and propagates, while for larger strain amplitudes several independent crack nucleation sites form, from which microcracks start propagating. It is also observed that the global plastic strain amplitude decreases from the initial to the final cycle, during total strain-controlled loading. However, this can even increase the crack growth rate because the crack advance is governed by the local plastic slip which accumulates at the crack tip over the number of cycles. With this work, it is shown that micromechanical modeling can strongly improve our understanding of the mechanisms of short-crack nucleation and growth under fatigue loading.

Fatigue of superelastic Nitinol in the mixed austenite–martensite state was examined in tension using center-tapered dog-bone specimens. A prestraining procedure, mimicking the load history of a medical device component, was applied prior to cycling: specimens were loaded to a fully martensitic state, unloaded partway into the lower plateau to a mixed-phase state, and then subjected to sinusoidal displacement cycles. Strain maps, obtained using digital image correlation, showed substantial variation in local mean and alternating strains across the gage section. In situ surface imaging using a high-speed camera confirmed crack initiation in a narrow transition zone between austenite and martensite that undergoes cyclic stress-induced martensitic transformation (SIMT). Fatigue life data showed an abrupt transition from high-cycle runouts to low-cycle fatigue failures at a stress amplitude level corresponding to the threshold for activating cyclic SIMT. The fatigue threshold can be estimated from the tensile loading–unloading curve.

Sintered nanoparticle structures are macroscopically brittle but quite robust if deposited on a flexible substrate. The effects of a polymer substrate on the stretchability of both brittle and ductile coatings and traces are well established. Systematic effects of substrate properties on the fatigue resistance of aerosol printed nano-Ag are slightly more complex. The present work is focused on the early stages of fatigue, where the resistance increases significantly but cracks are not yet visible. Overall, the fatigue behavior is seen to vary with the combination of substrate modulus and viscoelastic deformation properties. Comparing two common polyimides, the rate of damage was seen to increase faster with increasing amplitude on the less compliant one. Consistently with this increasing the minimum strain in the cycle led to a significantly stronger reduction in damage rates. However, the damage rate remained lower on the less compliant substrate at all amplitudes and strain ranges of practical concern.

The field of in situ nanomechanics is greatly benefiting from microelectromechanical systems (MEMS) technology and integrated microscale testing machines that can measure a wide range of mechanical properties at nanometer scales, while characterizing the damage or microstructure evolution in electron microscopes. This article focuses on the latest advances in MEMS-based nanomechanical testing techniques that go beyond stress and strain measurements under typical monotonic loadings. Specifically, recent advances in MEMS testing machines now enable probing key mechanical properties of nanomaterials related to fracture, fatigue, and wear. Tensile properties can be measured without instabilities or at high strain rates, and signature parameters such as activation volume can be obtained. Opportunities for environmental in situ nanomechanics enabled by MEMS technology are also discussed.

We aimed to examine the association between pain, stiffness and fatigue in newly diagnosed polymyalgia rheumatica (PMR) patients using baseline data from a prospective cohort study. Fatigue is a known, but often ignored symptom of PMR. Newly diagnosed PMR patients were recruited from general practice and mailed a baseline questionnaire. This included a numerical rating scale for pain and stiffness severity, manikins identifying locations of pain and stiffness and the FACIT-Fatigue questionnaire. A total of 652 PMR patients responded (88.5%). The mean age of responders was 72.6 years (SD 9.0) and the majority were female (62.0%). Manikin data demonstrated that bilateral shoulder and hip pain and stiffness were common. The mean fatigue score (FACIT) was 33.9 (SD 12.4). Adjusted regression analysis demonstrated that a higher number of pain sites (23–44 sites) and higher pain and stiffness severity were associated with greater levels of fatigue. In newly diagnosed PMR patients, fatigue was associated with PMR symptom severity.

Linear elastic moduli of solids with similar chemical compositions usually vary fairly insignificantly. However, for a broad class of apparently similar materials, their higher-order (nonlinear) moduli may differ by many times or even by orders of magnitude. Besides their large magnitude, nonlinear effects often demonstrate qualitative/functional features inconsistent with predictions of the classical theory of nonlinear elasticity based on consideration of weak lattice (atomic) nonlinearity. The latter is mostly applicable to ideal crystals and flawless amorphous solids, whereas the presence of structural heterogeneities can drastically modify the acoustic nonlinearity of materials without appreciable variation in the linear elastic properties. Despite often rather nontrivial/nonstraightforward relationships between microstructural features of the material and the resultant “nonclassical” acoustic nonlinearity, the extremely high structural sensitivity makes utilization of nonlinear acoustic effects attractive for a broad range of diagnostic applications that have been emerging in recent years in various areas—from seismic sounding and nondestructive testing to materials characterization down to the nanoscale.

Fatigue performance of metallic nanolayered composites (NLCs) has been gaining more and more attention due to the rapid development in the field of both micro-electro-mechanical systems and high-performance engineering structure materials and the increasing demand for long-term fatigue reliability. Metallic NLCs have exhibited different damage behaviors due to the effect of high-density heterogeneous interface compared with bulk materials and thin metal films. In this review paper, the cyclic deformation damage behavior, fatigue cracking feature, and fatigue properties of some metallic NLCs are reviewed. Effects of length scales, including layer thickness and grain size, on fatigue damage behaviors of the NLCs are revealed, and the transition of the fatigue cracking behavior and the corresponding damage mechanism are discussed. Then, the fatigue properties of some typical metallic NLCs are presented and compared with that of bulk materials and metal thin films. The effect of interface type and grain boundary alignment is also discussed to correlate with fatigue cracking resistance of the NLCs. Finally, some prospective research topics on fatigue performance of metallic NLCs are addressed.