Abstract
Wire arc additive manufacturing is a metal additive manufacturing technique that allows the fabrication of large size components at a high deposition rate. During wire arc additive manufacturing, multi-layer deposition results in heat accumulation, which raises the preheat temperature of the previously built layer. This causes process instabilities, resulting in deviations from the desired dimensions and variations in material properties. In the present study, a systematic investigation is carried out by varying the interlayer delay from 20 to 80 s during wire arc additive manufacturing deposition of the wall structure. The effect of the interlayer delay on the density, geometry, microstructure and mechanical properties is investigated. An improvement in density, reduction in wall width and wall height and grain refinement are observed with an increase in the interlayer delay. The grain refinement results in an improvement in the micro-hardness and compression strength of the wall structure. In order to understand the effect of interlayer delay on the temperature distribution, numerical simulation is carried out and it is observed that the preheat temperature reduced with an increase in interlayer delay resulting in variation in geometry, microstructure and mechanical properties. The study paves the direction for tailoring the properties of wire arc additive manufacturing-built wall structures by controlling the interlayer delay period.
Highlights
Metal Additive Manufacturing (MAM) is an advanced manufacturing technique for building complex three-dimensional components directly from 3D model data, which increases productivity and production flexibility over traditional manufacturing processes [1].Among the various MAM techniques, directed energy deposition (DED) is preferred over powder bed fusion (PBF) for producing large-size near-net-shaped components with a higher build rate [1,2]
It indicates the presence of humps and spatters during Wire arc additive manufacturing (WAAM) deposition
Density improvement is observed for higher delay sample and the wall width and height reduced with an increase in the interlayer delay due to reduction in the melt pool temperature; Grain refinement is observed with an increase in the interlayer delay due to a higher cooling rate and lower temperature gradient; 1
Summary
Metal Additive Manufacturing (MAM) is an advanced manufacturing technique for building complex three-dimensional components directly from 3D model data, which increases productivity and production flexibility over traditional manufacturing processes [1]. Discovered that the inter-layer dwell duration, which is directly connected to the thermal properties, has a substantial impact on the distortion and residual stresses in as-fabricated titanium and nickel alloy components Even though these modelling and experimental investigations have produced some valuable information, due to the complexity of the WAAM process, the underlying processes of arc characteristics and metal transfer behavior linked with heat accumulation remain poorly understood. One of the major challenges connected to the WAAM process is the dimensional deviations due to heat accumulation [13], as the thermal history largely impacts the geometry and microstructure, as seen in the literature. The heat accumulation rises with the number of layers and, the characteristics of WAAM structures can be controlled by varying the interlayer temperature during the process by utilizing specified dwell durations or forced cooling [17]. The present study seeks to examine the impact of various interlayer delays on the geometry, microstructure and mechanical characteristics
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