17 documents found, page 1 of 2
Mechanical Properties and Microstructural Characterization of Aged Nickel-based...
Silva, Cleiton Carvalho; Albuquerque, Victor Hugo Costa de; Miná, Émerson Mendonça; Moura, Elineudo Pinho de; Tavares, João Manuel R.S.The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy, as well as the influence of microstructural changes on the mechanical properties. The experiments addressed aging temperatures of 650 and 950 C for 10, 100, and 200 hours. The samples were analyzed by electron microscopy, microanalysis, and X-ray diffraction in ...
Thermal aging effects on the microstructure of Nb-bearing nickel based superall...
Albuquerque, Victor Hugo Costa de; Silva, Cleiton Carvalho; Normando, Paulo Garcia; Moura, Elineudo Pinho de; Tavares, João Manuel R.S.Secondary phases such as Laves and carbides are formed during the final stages of solidification of the nickel based superalloy Inconel 625 coatings deposited during the gas tungsten arc welding (GTAW) cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the c00 and d phases. The aim of this work was to evaluate the different phases formed during t...
Automatic microstructural characterization and classification using artificial ...
Nunes, Thiago M.; Albuquerque, Victor Hugo Costa de; Papa, João Paulo; Silva, Cleiton C.; Normando, Paulo Garcia; Moura, Elineudo Pinho deSecondary phases such as Laves and carbides are formed during the final solidification stages of nickel based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the c00 and d phases. This work presents a new application and evaluation of artificial intelligent techniques to classif...
Sistema computacional para determinação da taxa de diluição em soldadura
Rebouças Filho, Pedro Pedrosa; Cavalcante, Tarique da Silveira; Albuquerque, Victor Hugo Costa de; Silva, Cleiton Carvalho daDiluição da solda é a modificação da composição química do metal de adição, causada pela parcela do metal de base que sofreu fusão e passou a compor a zona fundida. Sendo dada pela percentagem do metal de base que participa na formação do cordão de solda. A sua medição, em geral, é obtida manualmente utilizando-se softwares genéricos de desenho ou de processamento e análise de imagem. Neste sentido, o presente ...
Effect of nonmetallic inclusion and banding on the success of the two-layer tem...
Albuquerque, Victor Hugo Costa de; Silva, Cleiton C.; Moura, Cícero R.O.; Aguiar, Willys Machado; Farias, Jesualdo PereiraThis work evaluated the effect of banding and nonmetallic inclusions in AISI 4140 steel on the HAZ toughness using the two-layer temper bead technique. The results showed that the amount and the length of the nonmetallic inclusions can negatively influence the toughness. There was a significant difference between the toughness of the materials with banding in the as-welded state and the heat treated. In conclus...
Spinodal decomposition mechanism study on the duplex stainless steel UNS S31803...
Albuquerque, Victor Hugo Costa de; Silva, Edgard de Macedo; Leite, Josinaldo Pereira; Moura, Elineudo Pinho de; Freita, Vera Lúcia de AraújoThis work, focuses on the spinodal decomposition mechanism study on the duplex stainless steel duplex UNS S31803, composed by austenite (c) and ferrite (a) phases, at 425 C and 475 C temperatures by ultrasonic speed measurements. This temperature range is responsible for the transformation mechanism of ainitial phase to a phases (poor in chromium) and a0 (rich in chromium) by spinodal decomposition. The techniq...
Phase transformations evaluation on a UNS S31803 duplex stainless steel based o...
Silva, Edgard de Macedo; Albuquerque, Victor Hugo Costa de; Leite, Josinaldo Pereira; Varela, Antonio Carlos Gomes; Moura, Elineudo Pinho deDuplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 ◦C, with the precipitation of the phase occurring over the ferritic microstructure. Aiming to character...
Ferramenta computacional para análise de imagens de ensaios mecânicos de dureza
Rebouças Filho, Pedro Pedrosa; Albuquerque, Victor Hugo Costa de; Cavalcante, Tarique da Silveira; Tavares, João Manuel Ribeiro da SilvaThis paper presents a computational tool capable of determining the Brinell and Vickers hardnesses from identation images. The tool integrates algorithms of image processing and analysis such as region growing and snakes. For validation purpose, the results obtained by the developed tool were compared with those obtained by the conventional process from identations made in ABNT 1020 steel. The comparison confir...
Biblioteca para implementação de controladores utilizando lógica fuzzy
Barros, Antonio Carlos da Silva; Albuquerque, Victor Hugo Costa de; Alexandria, Auzuir Ripardo deThe present work searchs to develop a library of Fuzzy Logic to implement the control in nonlinear systems, where, latery, it will be used in microcontrollers/microprocessors to execute several forms of control. The Fuzzy Logic is used, therefore it offers an easiness of work with control systems, and where nor always it is possible to make a simple mathematical modeling of the process. The used platform of dev...
Aplicação do método de contornos ativos radial para medição de dureza Brinell u...
Alexandria, Auzuir Ripardo de; Cortez, Paulo César; Almeida, Thomaz Maia de; Bessa, Jéssyca Almeida; Cavalcante, Tarique da SilveiraThe active contour methods have obtained good results in image segmentation when low signal/noise relationship is found. These techniques consist in the minimization of the total energy of the contours, calculated by the sum of the internal energy (function of the curve’s geometry) and the external energy (which depends on the characteristics of the image that is going to be segmented). Traditionally, the exter...