Dear Colleagues,

This Special Issue aims to investigate the current state-of-the-art of metals additive manufacturing, particularly concerning the recent developments focused on increasing this technology’s global performance and scalability.

Over the last several decades, the additive manufacturing of metals has gained notoriety among researchers, and is now available as an alternative industrial solution to overcome some of the limitations of traditional manufacturing processes, showing significant advantages in particular cases. However, as is known by the scientific community, many factors limit the scope of AM, mostly used today for specific applications and materials, requiring intense pre-manufacturing work (e.g., processes parameters selection, path planning, part slicing, automation, and materials criteria definition) in nearly trial-and-error methodology to produce a certain component. In this sense, the development and optimization of AM processes that minimize defects (e.g., lack of fusion and distortion), reduce pre-manufacturing time, and ensure a comparable reproducibility of the components’ performance to conventional processes are the key points to remodel the manufacturing chain and enable the scalability of AM. In this regard, research focused on thermal management in order to control the cooling rate and part geometry, process parameter monitoring and nondestructive testing, interlayer plastic deformation to improve mechanical properties, filler metal development and the use of inoculants to induce grain refinement of the microstructure, the definition of deposition strategies and open-source software development that optimize the cooling cycle and reduce distortion, computational process simulation, new heat-treatment sequences, analysis of AM material behavior in operational condition, etc., has been developed to maximize the capabilities of AM.

Therefore, in order to make metal AM a ready-to-use technology (similar to polymer AM) and considering the main proposal of this Special Issue, we welcome papers addressing topics including but not limited to the following:

• Development of process variants (through thermal, chemical, mechanical, geometric control, etc.);
• Evaluation and improvements on deposition stability and repeatability;
• Improvements in the deposition rate of processes;
• Improvements in the microstructural and mechanical properties of the deposited material;
• Exploration of the deposition of unconventional materials;
• Deposition of materials with a functional gradient;
• Exploration of unconventional features in AM technology;
• Determination and evaluation of heat treatments performed on parts produced by AM;
• Process monitoring, surface characteristics, defects, non-destructive testing, etc.;
• Development of thermomechanical analytical models and/or simulation to evaluate the part residual stresses, temperature distribution, and distortion;
• Improvements in deposition strategies (production time optimization, interlayer temperature control, influence on part properties, etc.);
• Development of resources dedicated to AM technology (power sources, new raw materials, torches, movement equipment, etc.);
• Evaluation of the efficiency of using substrate as part of the final component;
• Studies of AM parts’ performance in operational conditions, such as corrosion environments, fatigue loads, creep, wear, combined effects, etc.;
• Development and analysis of hybrid processes (arc+laser, arc+electron beam, additive+subtractive, etc.);
• AM selection criteria concerning traditional processes;
• Industries suitable for AM applications include nuclear/energy, oil and gas, automotive, and naval (note that studies in aeronautical applications will also be accepted; however, there is a lack of studies focused on other industrial niches);
• Machine learning algorithms applied to AM processes to improve weld appearance, avoid defects, control temperatures, etc.

We invite authors from academia and industry to submit original research and/or review papers that support the further development and improvement of AM technology.

Dr. Valdemar Rebelo Duarte
Guest Editor

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