Fatigue property-performance relationship of additively manufactured Ti-6Al-4V bracket for aero-engine application: An experimental study

In this paper, the Low Cycle Fatigue (LCF) performance of a weight optimized SLM Ti-6Al-4V bracket has been investigated. The bracket, a ‘struts & connectors’ shape for an aero-engine application, was designed to operate within the material elastic limit. The tensile and LCF fatigue data obtained from the coupon tests are discussed first which was then used to establish the loading levels for the LCF tests on the bracket. Cyclic softening was observed in the LCF coupon tests at strain levels higher than the material elastic limit, which was attributed to the pile-up of dislocations and formation of sub-grains in the SLM Ti-6Al-4V material. The SLM Ti-6Al-4V bracket met the LCF target cycles when operated near the material elastic limit and also when cycled at displacement levels causing plastic strain in the bracket elements. The carefully designed, weight optimized bracket has shown promising results in terms of its LCF performance and this provides a good encouragement to practicing engineers to adopt SLM technology for load bearing applications.