Selective Laser Melting (SLM) of magnesium alloys is the technology undergoing dynamic development in many research centres. The results are promising and make it possible to manufacture defect-free material with better properties than those offered by the manufacturing technologies used to date. This review aims to evaluate present state as well as main challenges of using Laser Powder Bed Fusion (L-PBF) for processing magnesium alloys as an alternative way to conventional technologies to manufacture parts in the aerospace industry. This literature review is the first one to outline information concerning the potential to use magnesium alloys in the aerospace industry as well as to summarise the results of magnesium alloy processing using AM technologies, in particular L-PBF. The available literature was reviewed to gather information about: the use of magnesium alloys in the aerospace industry—the benefits and limitations of using magnesium and its alloys, examples of applications using new processing methods to manufacture aerospace parts, the benefits and potential of using L-PBF to process metallic materials, examples of the use of L-PBF to manufacture aerospace parts, and state-of-the-art research into L-PBF processing of magnesium and magnesium alloys.

Purpose: This paper aims to discuss the results of material tests conducted on specimens manufactured from AZ31 alloy powder by selective laser melting (SLM) technology. The manufactured specimens were then subjected to porosity assessment, microstructure analysis as well as to mechanical and corrosion tests. Design/methodology/approach: SLM process was optimized using the design of experiments tools. Experiments aimed at selecting optimum process parameters were carried out in accordance with a five-level rotatable central composite design. Findings: The porosity results showed very low values of <1 per cent, whereas mechanical properties were close to the values reported for the reference wrought AZ31 alloy in hot-rolled state. A fine-grained microstructure was observed with a large range of grain size, which enhanced the material’s mechanical properties. Corrosion characteristics of the SLM-manufactured material exceed those determined for the wrought material. Originality/value: The results presented in this paper drive interest in magnesium alloys used in additive manufacturing processes. Low porosity, good mechanical properties, form of the microstructure and, most importantly, improved corrosion characteristics suggest that SLM provides great potential for the manufacture of ultralight structures, including resorbable metallic implants.

Additive manufacturing (AM) is dynamically developing and finding applications in different industries. The quality of input material is a part of the process and of the final product quality. That is why understanding the influence of powder reuse on the properties of bulk specimens is crucial for ensuring the repeatable AM process chain. The presented study investigated the possibility of continuous reuse of AlSi7Mg0.6 powder in the laser powder bed fusion process (LPBF). To date, there is no study of AlSi7Mg0.6 powder reuse in the LPBF process to be found in the literature. This study aims to respond to this gap. The five batches of AlSi7Mg0.6 powder and five bulk LPBF samples series were characterised using different techniques. The following characteristics of powders were analysed: the powder size distribution (PSD), the morphology (scanning electron microscopy—SEM), the flowability (rotating drum analysis), and laser light absorption (spectrophotometry). Bulk samples were characterised for microstructure (SEM), chemical composition (X-ray fluorescence spectrometry—XRF), porosity (computed tomography—CT) and mechanical properties (tensile, hardness). The powder was reused in subsequent processes without adding (recycling/rejuvenation) virgin powder (collective ageing powder reuse strategy). All tested powders (powders P0–P4) and bulk samples (series S0–S3) show repeatable properties, with changes observed within error limits. Samples manufactured within the fifth reuse cycle (series S4) showed some mean value changes of measured characteristics indicating initial degradation. However, these changes also mostly fit within error limits. Therefore, the collective ageing powder reuse strategy is considered to give repeatable LPBF process results and is recommended for the AlSi7Mg0.6 alloy within at least five consecutive LPBF processes.

One of the main limitations of additive manufacturing (AM) technologies consists in the relatively low build rate. Low productivity discourages companies from investing in AM machines, thus limiting the market of additive technologies. Machine manufacturers have introduced new solutions to their designs to increase the build rate, some of them are described in this paper. However, design improvements are not the only method to accelerate the process. The paper specifies factors that influence the build rate in the laser powder bed fusion process and provides an analytical assessment and comparison of the significance of how they affect its productivity. The influence that a change in selected parameters has on the process and the influence of multi-laser systems on its productivity are analysed in terms of the melted material quality. The processes from which the data for analysis were obtained were carried out on an SLM 280 machine with single- and dual-laser versions as well as on an SLM 500 with four lasers. Two types of samples, solid and thin-walled, both of the same volume, were tested. The data under analysis were the process times for both geometries, manufactured with different sets of parameters from the adopted range. Processing times were analysed to determine the main effects and interaction effects for extreme values of a given parameter. The height of the melted powder layer had the greatest influence on the build rate, which turned out to be greater even than the application of a two-laser system.