Details

Autor(en) / Beteiligte

• Hu, Y.N.
• Wu, S.C.
• Wu, Z.K.
• Zhong, X.L.
• Ahmed, S.
• Karabal, S.
• Xiao, X.H.
• Zhang, H.O.
• Withers, P.J.

Titel

A new approach to correlate the defect population with the fatigue life of selective laser melted Ti-6Al-4V alloy

Ist Teil von

• International journal of fatigue, 2020-07, Vol.136, p.105584, Article 105584

Ort / Verlag

Kidlington: Elsevier Ltd

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •The predominant failure is from near surface defects rather than the α′ phases.•The fatigue limit is predicted by the statistics of extreme and the Murakami model.•The Kitagawa-Takahashi diagram is extended to the finite life region.•The safe (infinite) life region is reformulated by the Chapetti model. Microstructural features and defects arising from selective laser melting (SLM) determine the in-service performance of additively manufactured near-net-shape components. Here the grain type, shape, size and distribution were characterized using electron backscattered diffraction (EBSD). High-resolution synchrotron radiation X-ray computed tomography (CT) was used to quantify the population, morphology and dimensions of porosity and lack of fusion defects. For SLM Ti-6Al-4V alloy, the larger-sized defects in comparison with the α grains are more important for crack initiation, typically leading to poor fatigue resistance and a pronounced variation in fatigue life. The fatigue strength was then evaluated in terms of the defect population using a combination of the statistics of extremes and the Murakami model. Finally, an extended Kitagawa-Takahashi fatigue diagram was established within the framework of defect-tolerant design, which includes a classical safe-life region and the defect-determined lifetime in the finite life region.