This research presents the results of different periods of T6 heat treatment (homogenization and artificial aging) for A356 aluminum alloy used in the fabrication of motorcycles. The samples were cast using gravity die casting, and industrial furnaces for T6 were used in the experiment. Two heat treatment conditions were used, with a total time of 7 h and 12 h, and the results were compared with the alloy without heat treatment. The effects of the reduction of treatment time on mechanical behavior were evaluated in terms of hardness, Charpy and tensile tests, as well as morphological analysis of fractures and microstructural behavior via optical microscopy, SEM-EDS, measurement of eutectic Si evolution, and XRD. Excellent mechanical properties were achieved with a treatment period of 7 h, which achieved a yield strength of 226.58 (±3.76) MPa, tensile strength limit of 264.78 (±4.27) MPa and elongation of 3.41 (±0.47) %. This is competitive with other cast alloys subjected to T6 heat treatment in longer treatment cycles. The peak of hardness and highest impact resistance was recorded for the sample treated for 12 h; however, in the impact test, there was no significant difference between the two experiments.

O alumínio é o terceiro metal mais abundante no planeta, sendo amplamente utilizado em indústrias desde pequenos componentes a grandes materiais, sendo utilizados nas indústrias automobilísticas e aeroespaciais, bem como em pesquisas científicas e tecnológicas. Neste trabalho o objetivo foi de realizar uma análise comparativa de amostras, após processo de tratamento térmico de envelhecimento artificial (T6), nas microestruturas das ligas de A356 e AC2B. Os métodos utilizados foram de caracterização dos materiais, como ensaios de metalografia, macroestrutura, microestrutura, microdureza e técnica de microscopia óptica. As amostras de A356 e AC2B foram submetidas ao processo de solubilização à 400 ± 5 °C, durante 6h e ao processo de envelhecimento artificial (T6) à 140 e 160 ± 5 °C, em diferentes tempos. Em ambos os processos as peças foram resfriadas à temperatura ambiente. Conforme observações gráficas e dados apresentados, a variação de tempo e temperatura no envelhecimento artificial das ligas A356 e AC2B, apresentaram respectivamente, resultados com alterações diretamente proporcionais na microdureza das ligas, atingindo o envelhecimento na evolução das propriedades mecânicas das ligas analisadas.

Aluminum is the third most abundant metal in the earth's crust and is widely used in the automotive, aerospace and scientific research industries due to its properties such as lightness, mechanical and corrosion resistance. The aim of this work was to comparatively analyze the microstructures of aluminum alloys A356 and AC2B after T6 artificial aging heat treatment. The samples were solubilized at 400 ± 5 °C for 6 hours, followed by aging at 140 °C and 160 ± 5 °C, with time variations. The samples were cooled to room temperature. Characterization methods such as metallography, macro and microstructural analysis, microhardness testing and optical microscopy were used. The results showed that the variation in ageing time and temperature directly influenced the microhardness of the alloys, improving their mechanical properties. It is concluded that the T6 treatment contributes to improving the structural performance of the alloys and is effective for applications requiring greater strength and reliability

With the collapse of the COVID-19 pandemic, it was necessary to explore new materials with resistance to SARS- CoV-2 of lower cost and effective and easy production methods, such as 3D printing. The objective was to produce and characterize filaments for 3D printing using PETG and copper nanoparticles (NCu) aiming at obtaining a virucidal surface. Nanocomposites were made with the addition of 0.75% and 1% of NCu and pure PETG. After printing, mechanical tests of nanoindentation, thermogravimetric analyses (TGA), digital optical microscopies and Fourier transform infrared spectroscopies (FTIR) were performed. The results showed a 48% increase in the elastic modulus for the 0.75% and 1% nanocomposites compared to pure PETG. In the TGA, the results were significant for the nanocomposites with the addition of 1% of NCu compared to pure PETG. In the chemical composition by FTIR spectrum, there were no significant changes.

Welding is a manufacturing process that aims to create a permanent joint between two components using parameters such as heat, pressure, or energy. It is currently one of the most widely used processes in industry and there are no concerns about the safety of the products produced. Welding gases are responsible for the protection of the weld pool and the stability of the electric arc, which directly affects the quality and final properties of the weld. The aim of this study was to evaluate the current conditions of the welding process in a large company in the Manaus Industrial Pole (PIM), Amazonas-Brazil, in order to find the best ratio of shielding gases for MIG/MAG welding, with the aim of and optimizing the processes. Mechanical tensile and microhardness tests were carried out, based on JIS, ASTM and internal company standards, to evaluate the conditions and properties of the samples with the current shielding gas ratios used in the company, in order to find those that best match the reality of the processes. Keywords: Shielding gases; MIG/MAG welding; Mechanical properties of the weld.

The COVID-19 pandemic has highlighted the need to develop new materials with antiviral properties that are low cost and easy to manufacture, such as those obtained through 3D printing. This work aimed to produce and characterize PETG filaments with added copper nanoparticles (NCu), looking for virucidal properties. Filaments were prepared with 0%, 0.75% and 1% NCu and samples were then printed in 3D. The samples were subjected to nanoindentation tests, thermogravimetric analysis (TGA) and digital optical microscopy. The results indicated an increase of approximately 48% in the modulus of elasticity of the nanocomposites with 0.75% and 1% NCu compared to pure PETG. TGA analysis showed that the nanocomposite with 1% NCu had greater thermal stability, with degradation starting at 402 °C, 19 °C higher than pure PETG. In addition, this material showed a second degradation peak and a mass loss of up to 90%, compared to 15% observed in pure PETG. The data obtained shows that the addition of NCu to PETG can significantly improve its mechanical and thermal properties, making it promising for applications requiring resistance and virucidal action.