Navegando por Assunto "Mechanical propertiers"

Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Influência da adição de nanotubos de carbono nas propriedades mecânicas da liga AL-2%NI solidificadas direcionalmente
(Universidade Federal do Pará, 2015-11-27) NASCIMENTO, Luiz Gabriel da Silva; SÁ, Fernando Antônio de; http://lattes.cnpq.br/8275621144223544; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
In this work, we produced a hypoeutectic Al-2wt%Ni matrix, to which we added various concentrations of carbon nanotubes, in order to evaluate the evolution of the mechanical strength of the new material. The manufacturing process occurred by melting and ascending unidirectional abrupt cooling, with extraction of the heat transient and determination of the thermal variables involved in the solidification. Scanning Electron Microscopy images show how the nanotubes are settled in the matrix, and by means of Raman Spectroscopy, we were able to determine the “D” and “G” bands and analyze the action of the process over them. By means of metallographic and mechanical tests, we were able to characterize the macro and micro-structural behaviors and the mechanical properties. The addition of small quantities of nanotubes led to a significant raise in the mechanical strength of the matrix.
Acesso aberto (Open Access)
Reforço superficial em alumínio fundido por nanotubos de carbono via tratamento de solubilização
(Universidade Federal do Pará, 2021-10-14) BRITO, Paulo Roberto de Oliveira; REIS, Marcos Allan Leite dos; http://lattes.cnpq.br/8252507933374637
Carbon nanotubes (CNTs) are noteworthy, as they reinforce the metallic matrix, due to mechanical properties, such as the ~ 1.0 TPa Young module. To improve the maintenance of the commercially pure aluminum surface, multi-walled carbon nanotubes (MWCNTs) were incorporated into the aluminum surface with heat treatment by solid solubilization, in order to improve the surface properties of aluminum. The aluminum samples were subjected to chemically attacked with the Keller reagent, for a period of 30, 60 and 120 seconds, and soon after the roughness assessment was carried out, and then they were placed in a container containing NTCs, being subjected to a 640°C for one hour. Afterwards, the morphology was evaluated in the scanning electron microscope, where an aggregate of NTCs was observed, the DRX was performed to evaluate the addition of the NTCs in the matrix, and the Raman Spectrum that evaluated the charge transfer to the matrix. Microhardness was performed to evaluate the result of the incorporation of the NTCs in the matrix. The results obtained show that the incorporation of CNTs in the aluminum matrix increases the hardness in approximately 20% of the surface, in comparison with the control sample. The process of incorporating CNTs into the aluminum matrix by solubilization is a promising, simple and inexpensive alternative to improve the durability of the aluminum surface.