Characterization of fatigue crack growth behavior in LENS fabricated Ti-6Al-4V using high-energy synchrotron x-ray microtomography

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• 作者：Hayley R. Sandgren^a ; Yuwei Zhai^b ; ^{yzhai@wpi.edu" class="auth_mail" title="E-mail the corresponding author} ; Diana A. Lados^b ; Paul A. Shade^c ; Jay C. Schuren^d ; Michael A. Groeber^c ; Peter Kenesei^e ; Anastasios G. Gavras^f
• 关键词：LENS fabricated Ti-6Al-4V ; High-energy synchrotron x-ray microtomography ; 3D characterization of fatigue crack growth
• 刊名：Additive Manufacturing
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：12
• 期：part_PA
• 页码：132-141
• 全文大小：5824 K

文摘

Laser Engineered Net Shaping (LENS) is an additive manufacturing technique that belongs to the ASTM standardized directed energy deposition category. To date, very limited work has been conducted towards understanding the fatigue crack growth behavior of LENS fabricated materials, which hinders the widespread adoption of this technology for high-integrity structural applications. In this study, the propagation of a 20 μm initial crack in LENS fabricated Ti-6Al-4V was captured in-situ, using high-energy synchrotron x-ray microtomography. Fatigue crack growth (FCG) data were then determined from 2D and 3D tomography reconstructions, as well as from fracture surface striation measurements using SEM. The generated data were compared to those obtained from conventional FCG tests that used compliance and direct current potential drop (DCPD) techniques to measure long and small crack growth. The observed agreement demonstrates that x-ray microtomography and fractographic analysis using SEM can be successfully combined to study the propagation behavior of fatigue cracks.