Abstract
Additive manufacturing processes have gained prominence in recent years as they allow the fabrication of parts of complex geometries while reducing the number of operations required. Therefore, several applications have already been envisioned, among which we can mention the manufacture of molds and dies. Typically, hot working steels are used for these applications, such as the AISI H13 tool steel, which will be the subject of this study. Initially, a processing window will be determined from the variation of the most influential parameters: laser power and scanning speed. The densification, microstructure and properties of the deposited material will be evaluated, which will be related to the thermal history. Then, three routes of post-processing heat treatments will be evaluated: (i) direct tempering; (ii) quenching and tempering; and (iii) stress relief, quenching and tempering. The evaluation of these thermal treatments will be done by high-temperature in-situ x-ray diffraction tests, microstructural analysis and mechanical properties (tensile/compression tests, fracture toughness and wear). Thus, it will be possible to correlate the obtained microstructures with the phase transformations and the mechanical performance of the parts, besides optimizing the treatments as a function of the transformation kinetics. In the development of this project, advanced materials characterization techniques will be used, such as transmission electron microscopy and three-dimensional atom probe tomography to study the phenomena of destabilization of retained austenite, martensite tempering and precipitation of carbides. Thus, the data collected in this project will be of fundamental importance for the implementation of the additive manufacturing on an industrial scale, with information on the processing and post-processing conditions, as well as presenting a significant increase in the metallurgy of tool steels. In the future, the information gathered by this study may also be used in the development of specific commercial alloys for additive manufacturing, from an understanding of the microstructural phenomena that lead to an increase in the mechanical properties of these materials. (AU)
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