An investigation of fatigue of additively manufactured commercially pure Alpha–Ti alloy at 350 °C

Balakumar, T.; Riahi, R.; Edrisy, A.

doi:10.1016/j.jmrt.2023.09.055

Cited by 5 publications

(6 citation statements)

References 29 publications

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“…The main components of the RBF tester, including the specimen-collet assembly, heating unit, temperature controller, poise weight, and cycle counter, are labeled in Figure 1b. The current experimental fatigue data for AM Ti-TiB MMCs at 350 °C in the 45° and 90° AM build directions along with fatigue data from the literature [31] in the 0° AM build direction at 350 °C are presented in Figure 2 as a plot of stress amplitude (σ) against the number of cycles to failure ( ). The electron microscopy images collected from the fractured fatigue specimens as well as from polished and etched specimens with 0°, 45°, and 90° AM build directions are given in Figures 3-6.…”

Section: Specimen Orientations and Experimental Resultsmentioning

confidence: 99%

“…The electron microscopy images collected from the fractured fatigue specimens as well as from polished and etched specimens with 0°, 45°, and 90° AM build directions are given in Figures 3-6. The specimens that were polished and etched were cut in such a manner that representative cross sections of the fatigue specimens with 0°, 45°, and 90° The current experimental fatigue data for AM Ti-TiB MMCs at 350 °C in the 45° and 90° AM build directions along with fatigue data from the literature [31] in the 0° AM build direction at 350 °C are presented in Figure 2 as a plot of stress amplitude (σ) against the number of cycles to failure ( ). The electron microscopy images collected from the fractured fatigue specimens as well as from polished and etched specimens with 0°, 45°, and 90° AM build directions are given in Figures 3-6.…”

Section: Specimen Orientations and Experimental Resultsmentioning

confidence: 99%

“…Among these three AM directions, experimental data on the 45 • and 90 • AM build directions were collected in the present study. Data on the 0 • AM build direction at 350 • C were extracted from the current authors' previous experimental work reported in [31]. Further, the fatigue data for the current work were collected using a rotating beam fatigue (RBF) tester following the experimental setup described in [31].…”

Section: Introductionmentioning

confidence: 99%

“…Data on the 0 • AM build direction at 350 • C were extracted from the current authors' previous experimental work reported in [31]. Further, the fatigue data for the current work were collected using a rotating beam fatigue (RBF) tester following the experimental setup described in [31]. Moreover, to investigate the influence of TiB on crack initiations, propagations, and the overall directional fatigue strength of Ti-TiB MMCs, electron microscopy images were collected from polished as well as fatigue fractured specimens.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, to investigate the influence of TiB on crack initiations, propagations, and the overall directional fatigue strength of Ti-TiB MMCs, electron microscopy images were collected from polished as well as fatigue fractured specimens. In addition to the current fatigue and electron microscopy experimental work, an analytical investigation on the fatigue life predictability of the modified Paris equation described in [31] was tested against the general Paris equation using current and literature [31] experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Analytical Study of Directional Isothermal Fatigue in Additively Manufactured Ti-TiB Metal Matrix Composites

Balakumar,

Riahi,

Edrisy

2024

Metals

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Additive manufacturing (AM) techniques are widely investigated for the cost-effective use of titanium (Ti) alloys in various aerospace applications. One of the AM techniques developed for such applications is plasma transferred arc solid free-form fabrication (PTA-SFFF). Materials manufactured through AM techniques often exhibit anisotropies in mechanical properties due to the layer-by-layer material build. In this regard, the present study investigates the isothermal directional fatigue of a Ti-TiB metal matrix composite (MMC) manufactured by PTA-SFFF. This investigation includes a rotating beam fatigue test in the fully reversed condition (stress ratio, R = −1), electron microscopy, and calculations for fatigue life predictions using Paris’ and modified Paris’ equations. The fatigue experiments were performed at 350 °C using specimen with the test axis oriented diagonally (45°) and parallel (90°) to the AM builds directions. The fatigue values from the current experiments along with literature data find that the Ti MMC manufactured via PTA-SFFF exhibit fatigue anisotropy reporting highest strength in 90° and lowest in perpendicular (0°) AM build directions. Furthermore, calculations were performed to evaluate the optimum values of the stress intensity modification factor (λ) for fatigue life prediction in 0°, 45°, and 90° AM build directions. It was found that for the specimens with 45°, and 90° AM build directions, the computed intensity modification factors were very similar. This suggests that the initial fatigue crack characteristics such as location, shape, and size were similar in both 45°, and 90° AM build directions. However, in 0° AM build direction, the computed stress intensity modification factor was different from that of the 45°, and 90° AM build directions. This indicates that the fatigue crack initiation at 0° AM build direction is different compared to the other two directions considered in this study. Moreover, the quality of fatigue life prediction was assessed by calculating R2 values for both Paris and modified Paris predictions. Using the R2 values, it was found that the fatigue life predictions made by the modified Paris equation resulted in improved prediction accuracy for all three builds, and the percentage improvement ranged from 30% to 60%. Additionally, electron microscopy investigations of 0°, 45°, and 90° AM build specimens revealed extensive damage to the TiB particle compared to the Ti matrix as well as frequent TiB clusters in all three AM build directions. These observations suggest that the spread of these TiB clusters plays a role in the fatigue anisotropy of Ti-TiB MMCs.

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Section: Specimen Orientations and Experimental Resultsmentioning

confidence: 99%

Section: Specimen Orientations and Experimental Resultsmentioning

confidence: 99%