Details

Autor(en) / Beteiligte

• Poyraz, Ozgur
• Kushan, Melih Cemal

Titel

Residual Stress-induced Distortions in Laser Powder Bed Additive Manufacturing of Nickel-based Superalloys

Ist Teil von

• Strojniski Vestnik - Journal of Mechanical Engineering, 2019-01, Vol.65 (6), p.343-350

Ort / Verlag

University of Ljubljana, Faculty of Mechanical Engineering

Erscheinungsjahr

2019

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• One of the significant process limits of laser powder bed additive manufacturing technologies is residual stresses and distortions induced by heating the fine metal powder to the melting point and sudden cooling to the initial temperature. While this phenomenon applies to most types of metal alloys, it becomes more important in nickel-based superalloys, which have low thermal conductivity and high-quality requirements for aerospace utilization. Together with the mechanical integrity and geometric problems in the final product, residual stress-induced distortions carry the potential risk of interrupting the job process above a certain distortion limit as a result of part-to-re-coater rubbing. Process simulations performed in a computer environment are of critical importance to predict and to prevent this risk. However, simulation models need to be verified through experiments, and they need to be cost-effective in terms of simulation times. This paper presents a comprehensive study to introduce a fast thermo-mechanical simulation model, together with experiments on nickel-based superalloy demonstrators. It also contributes to the scientific knowledge base with novel coupon design, manufacturing and evaluation methodology for distortion studies. Keywords: additive manufacturing, finite element analysis, laser powder bed fusion, thermo-mechanical simulations Highlights * A fast thermo-mechanical finite element model was introduced for the analysis of distortions and residual stresses in laser powder bed additive manufacturing. * Novel benchmark coupons were designed for the benchmarking of residual stress-induced distortions considering circumferential effects. * The thermo-mechanical finite element model was employed for the simulation of benchmark coupons. * Experiments were conducted for an Inconel 718 nickel-based superalloy using a laser powder bed fusion additive manufacturing system * Results were evaluated via a coordinate measuring machine equipped with a laser scanner head. * Successful convergence was achieved with the experimental results.