Modelling Creep and Creep Crack Growth of LPBF alloy 718

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Components manufactured by laser powder bed fabrication (LPBF) are fundamentally limited by their performance for use in critical applications. With respect to high temperature materials produced via LPBF, microstructural defects - such as unfavourable precipitate formation, suboptimal grain size and distribution - and macroscale anomalies - like lack of fusion, intra/inter layer defects - often result in LPBF components performing well below their wrought counterparts.In this work, alloy 718 parts, fabricated using a quad-laser Renishaw machine with different scanning strategies, build orientations and number of lasers, were creep tested at 650 under a 600 MPa load. For a given strategy, a 24% increase in creep life compared to wrought alloy 718 was observed. The build 0rientation was also shown to be a determining factor in the creep failure mechanism.Modelling of creep and Creep crack growth work is underway. It is therefore possible, as a result of this work, to propose build strategies for high temperature creep applications and be able to accurately predict LPBF alloys creeep performance.