Rui F. Martins , Ricardo Branco , José Camacho , Wojciech Macek , Zbigniew Marciniak , António Silva , Cândida Malça
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引用次数: 0
Abstract
The selective laser melting (SLM) process, a type of laser powder-bed fusion (LPBF) in additive manufacturing (AM), uses a high-power density laser to melt metallic powders. This study involved 3D printing Compact Tension (CT) specimens from titanium alloy Ti6Al4V, known for its rigidity, corrosion resistance, and biocompatibility, making it suitable for aerospace and medical applications.
To predict fatigue life, it is essential to assess fatigue crack growth rates (FCGR) in the presence of cracks. This investigation tested three printing strategies − transversal, longitudinal, and cross − under constant amplitude loading (R = 0.2) and compared the results with reference titanium alloys. Scanning electron microscopy (SEM) was used to analyze the fracture surfaces.
The results indicated that the as-built AM transversal CT specimens (R = 0.2) had superior FCGR compared to the longitudinal and cross specimens, closely matching those of SLM-produced Ti6Al4V heat-treated at 670 °C (R = 0.05). The transverse deposition mode yielded the best performance, with fracture surfaces exhibiting mainly transgranular propagation. In addition, fracture surface topography measurements showed a strong correlation with fatigue life, particularly the relationship between the mean depth of furrows and the number of cycles to failure.
期刊介绍:
Typical subjects discussed in International Journal of Fatigue address:
Novel fatigue testing and characterization methods (new kinds of fatigue tests, critical evaluation of existing methods, in situ measurement of fatigue degradation, non-contact field measurements)
Multiaxial fatigue and complex loading effects of materials and structures, exploring state-of-the-art concepts in degradation under cyclic loading
Fatigue in the very high cycle regime, including failure mode transitions from surface to subsurface, effects of surface treatment, processing, and loading conditions
Modeling (including degradation processes and related driving forces, multiscale/multi-resolution methods, computational hierarchical and concurrent methods for coupled component and material responses, novel methods for notch root analysis, fracture mechanics, damage mechanics, crack growth kinetics, life prediction and durability, and prediction of stochastic fatigue behavior reflecting microstructure and service conditions)
Models for early stages of fatigue crack formation and growth that explicitly consider microstructure and relevant materials science aspects
Understanding the influence or manufacturing and processing route on fatigue degradation, and embedding this understanding in more predictive schemes for mitigation and design against fatigue
Prognosis and damage state awareness (including sensors, monitoring, methodology, interactive control, accelerated methods, data interpretation)
Applications of technologies associated with fatigue and their implications for structural integrity and reliability. This includes issues related to design, operation and maintenance, i.e., life cycle engineering
Smart materials and structures that can sense and mitigate fatigue degradation
Fatigue of devices and structures at small scales, including effects of process route and surfaces/interfaces.