Improving the fatigue behaviour of a selectively laser melted aluminium alloy: Influence of heat treatment and surface quality

Aboulkhair, Nesma T.; Maskery, Ian; Tuck, Christopher; Ashcroft, Ian; Everitt, Nicola M.

Abstract

Selective laser melting (SLM) is being widely utilised to fabricate intricate structures used in various industries. Widening the range of applications that can benefit from such promising technology requires validating SLM parts in load bearing applications. Recent studies have mainly focussed on static loading, with minor attention to cyclic loading despite its vital importance in many applications. In this work, the fatigue performance of SLM AlSi10Mg was investigated considering the effects of surface quality and heat treatment. Compared to heat treatment, machining the samples played a minor role in improving the fatigue behaviour. This is potentially attractive to industries interested in latticed structures and topology-optimised parts where post-processing machining is not feasible. The characteristically fine microstructure in the as-built samples provided good fatigue crack propagation resistance but none of them survived nominal fatigue life of 3 × 107 cycles within the maximum stress range of 63–220 MPa. A specially-tailored heat treatment increased the material's ductility, significantly improving its fatigue performance. At 94 MPa, the heat-treated samples survived beyond the nominal fatigue life, outperforming the reference cast material. The combined effect of machining and heat treatment yielded parts with far superior fatigue properties, promoting the material for a wider range of applications.

Citation

Aboulkhair, N. T., Maskery, I., Tuck, C., Ashcroft, I., & Everitt, N. M. (2016). Improving the fatigue behaviour of a selectively laser melted aluminium alloy: Influence of heat treatment and surface quality. Materials and Design, 104, 174-182. https://doi.org/10.1016/j.matdes.2016.05.041

• Journal Article Type: Article
• Acceptance Date: May 12, 2016
• Online Publication Date: May 13, 2016
• Publication Date: Aug 15, 2016
• Deposit Date: May 20, 2016
• Publicly Available Date: May 20, 2016
• Journal: Materials & Design
• Print ISSN: 0261-3069
• Electronic ISSN: 0264-1275
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 104
• Pages: 174-182
• DOI: https://doi.org/10.1016/j.matdes.2016.05.041
• Keywords: Additive manufacture; selective laser melting; aluminium alloys; microstructure; fatigue; heat treatment
• Public URL: https://nottingham-repository.worktribe.com/output/805491
• Publisher URL: http://dx.doi.org/10.1016/j.matdes.2016.05.041
• Contract Date: May 20, 2016