Digitisation of metal AM for part microstructure and property control

Abstract

Metal additive manufacturing, which uses a layer-by-layer approach to fabricate parts, has many potential advantages over conventional techniques, including the ability to produced complex geometries, fast new design part production, personalised production, have lower cost and produce less material waste. While these advantages make AM an attractive option for industry, determining process parameters which result in specific properties, such as the level of porosity and tensile strength, can be a long and costly endeavour. In this review, the state-of-the-art in the control of part properties in AM is examined, including the effect of microstructure on part properties. The simulation of microstructure formation via numerical simulation and machine learning is examined which can provide process quality control and has the potential to aid in rapid process optimisation via closed loop control. In-situ monitoring of the AM process, is also discussed as a route to enable first time right production in the AM process, along with the hybrid approach of AM fabrication with post-processing steps such as shock peening, heat treatment and rolling. At the end of the paper, an outlook is presented with a view towards potential avenues for further research required in the field of metal AM.

Optimization of laser irradiation process parameters for 40Cr steel based on back propagation neural network and genetic algorithm

“…When the yield limit of the material is reached, plastic deformation occurs. When the deformation is unobvious, the stress can be expressed as a linear combination with the strain, the elastic deformation is described by Hooke's law 24 σ = E:ε el (13) where σ is the elastic stress and E is the modulus of elasticity.…”

“…Numerical simulation can effectively compensate for the shortcomings of experimental methods and avoid the waste of energy and materials caused by repeated experiments and attempts. 13 Therefore, it is significant to construct a multi-field coupling model that interconnects the temperature, phase transition, and stress during the laser quenching, as it holds significant implications in optimizing the laser irradiation process parameters of 40Cr steel.…”

Effect of Solution Heat Treatment on the Microstructure and Crystallographic Texture of In939 Fabricated by Powder Bed Fusion-Laser Beam

“…The grain morphology (i.e., planar, cellular structure and columnar dendrites) of the samples fabricated with additive manufacturing methods is mainly dependent on the ratio of the thermal gradient (G) to the solidification rate (R) which is described as the G/R ratio [26,27]. It can be said that the G/R ratio for the PBF-LB processing is relatively low due to the rapid solidification rate ((10 3 e10 8 K/s) [28].…”