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Introdução de inoculantes em peças de Inconel 625 produzidas por fabrico aditivo por arco e fio
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Resumo(s)
O fabrico aditivo por arco e fio (WAAM) é um processo que apresenta taxas de
deposição elevadas, com maior liberdade nas dimensões das peças a fabricar e um considerável
aproveitamento do material. Apresenta como principais desvantagens a criação de tensões
residuais e anisotropia nas peças fabricadas.
Este trabalho teve como objetivo principal melhorar as propriedades mecânicas das
superligas de níquel e reduzir a anisotropia. Para materializar o objetivo proposto
desenvolveu-se um protótipo capaz de introduzir os inoculantes TiC, TiB2 e SiC nas peças
fabricadas por WAAM com base no GMAW, avaliando o seu desempenho em Inconel 625.
Este trabalho permitiu concluir que, face à amostra base, as amostras com inoculantes
apresentaram mais fases Laves e δ, verificando-se um refinamento da microestrutura e um
pequeno aumento da microdureza. Constatou-se ainda um aumento da σc na direção vertical
nas amostras com TiC e com TiB2, e um aumento na direção horizontal nas amostras com TiB2
e com SiC. A amostra com partículas de TiB2 revelou isotropia na σc. Verificou-se também
uma diminuição significativa da σ70%ε na direção horizontal em todas as amostras com
inoculantes e um aumento, embora reduzido, na direção vertical, nas amostras com partículas
de TiC e de SiC.
Este trabalho permitiu corroborar que o protótipo pode ser utilizado na introdução de
inoculantes no WAAM e que este processo pode ser utilizado para a produção de paredes de
Inconel 625, contudo, importa aferir o tamanho dos grãos e as tensões de rotura e de fratura.
WAAM is an additive manufacturing process that presents high deposition rates, with greater freedom in the dimensions of the parts to be manufactured and a better use of material. Its main disadvantages are the creation of residual stresses and anisotropy in the manufactured parts. The main objective of this work was to improve the mechanical properties of nickel superalloys and reduce anisotropy. To fulfill the proposed objective, a prototype capable of introducing TiC, TiB2 and SiC inoculants was developed and used to manufacture parts using GMAW based WAAM, evaluating their performance in Inconel 625. With this work it was concluded that, comparing to the base sample, the samples with inoculants had more Laves and δ phases, a more refined microstructure and a small increase in microhardness. There was also an increase in σy in the vertical direction in samples with TiC and TiB2, and an increase in the horizontal direction in samples with TiB2 and with SiC. The sample with TiB2 particles revealed isotropy in σy. There was also a significant decrease of σ70%ε in the horizontal direction in all samples with inoculants and a reduced increase in the vertical direction in samples with TiC and SiC particles. This work confirms that the prototype can be used in the introduction of inoculants in walls produced by WAAM and that this process can be used for the production of Inconel 625 walls, however, it is important to measure the size of the grains and the ultimate and fracture stresses.
WAAM is an additive manufacturing process that presents high deposition rates, with greater freedom in the dimensions of the parts to be manufactured and a better use of material. Its main disadvantages are the creation of residual stresses and anisotropy in the manufactured parts. The main objective of this work was to improve the mechanical properties of nickel superalloys and reduce anisotropy. To fulfill the proposed objective, a prototype capable of introducing TiC, TiB2 and SiC inoculants was developed and used to manufacture parts using GMAW based WAAM, evaluating their performance in Inconel 625. With this work it was concluded that, comparing to the base sample, the samples with inoculants had more Laves and δ phases, a more refined microstructure and a small increase in microhardness. There was also an increase in σy in the vertical direction in samples with TiC and TiB2, and an increase in the horizontal direction in samples with TiB2 and with SiC. The sample with TiB2 particles revealed isotropy in σy. There was also a significant decrease of σ70%ε in the horizontal direction in all samples with inoculants and a reduced increase in the vertical direction in samples with TiC and SiC particles. This work confirms that the prototype can be used in the introduction of inoculants in walls produced by WAAM and that this process can be used for the production of Inconel 625 walls, however, it is important to measure the size of the grains and the ultimate and fracture stresses.
Descrição
Palavras-chave
Fabrico aditivo WAAM Inconel 625 inoculação TiC TiB2