Poliana Souza

State University of Paraiba-UEPB, Brazil, Administração, Graduate Student

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Miguel Angel Narvaez Ardila

Universidade Federal de Uberlândia

Antônio César Bozzi

Universidade Federal do Espirito Santo

Helio Goldenstein

Rodrigo Galo

Universidade de São Paulo

Wallisson Silva

Marcus Perez

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Papers by Poliana Souza

Análise do comportamento do par tribológico aço alto carbono e alto silício (HC-HSi) contra pinos com substrato de metal duro e cermet em ensaios de pino sobre disco

The Journal of Engineering and Exact Sciences, 2022

Durante as últimas décadas, estudos envolvendo a estrutura bainítica tem atraído pesquisadores po... more Durante as últimas décadas, estudos envolvendo a estrutura bainítica tem atraído pesquisadores por combinar elevada resistência e alta ductilidade. Aços bainiticos são potencialmente úteis em estruturas que sofrem fadiga de rolamento e/ou deslizamento, por exemplo trilhos ferroviários, componentes de mineração, rolamentos e eixos. Essas propriedades mecânicas têm sido obtidas, elaborando cuidadosamente o projeto da liga e adequado tratamento térmico de austêmpera. No entanto, o material com essas propriedades tende a prejudicar a usinabilidade nos processos de manufatura, fazendo-se necessário usinar o material no estado recozido. Este trabalho tem por objetivo contribuir com a análise tribológica do contato entre aço fundido no estado recozido contra metal duro e cermet (revestidos com Nitreto de Titânio (TiN)), que são materiais amplamente encontrados em ferramentas de corte. Para isso, foram realizados ensaios de pino sobre disco (PSD), de modo a analisar as evoluções do coeficie...

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Study on the surface integrity of AISI 4140 steel after turning

Machine components are usually subjected to cyclic loads, which may lead to failure, even when th... more Machine components are usually subjected to cyclic loads, which may lead to failure, even when the component is subjected to elastic deformations only. Manufacturing processes are capable of affecting roughness and inducing residual stresses of distinct levels and depths, being able to affect the component performance and lifespan. This work investigates the influence of turning parameters (cutting speed, feed and depth of cut) on surface roughness, residual stress and fatigue life of hardened AISI 4140 steel (40 HRC). Feed is the most influential parameter affecting surface roughness. It was noticed that the cutting parameters did affect the residual stress profile, i.e., tensile residual stresses of higher intensity were induced when higher cutting speeds were employed and reaching deeper layers when higher feed and lower depth of cut values were used. The fatigue life was evaluated under rotating bending tests, which indicated a combined influence of feed and depth of cut. At low...

Formation of White Etching Layers by Deep Rolling of AISI 4140 Steel

Journal of Materials Engineering and Performance, 2020

Deep rolling is an effective mechanical surface treatment method; however, the induced deformatio... more Deep rolling is an effective mechanical surface treatment method; however, the induced deformation may eventually lead to changes that result in a structure known as a white etching layer (WEL). The WEL possesses a distinct constitution and properties compared with the surrounding bulk material. The presence of the WEL drastically affects the surface integrity of the part and impairs the performance of the metallic components. However, the influence of deep rolling on WEL formation has not been fully clarified. Therefore, the goal of this study was to investigate WEL formation after deep rolling AISI 4140 steel with various microstructures (obtained through four heat treatment routes) and employing distinct rolling pressure and feed values. The results show that larger lattice distortion (resulting from refined martensitic structures) and higher deep rolling feed (increased work hardening) lead to the formation of a thicker WEL. Moreover, the increase in rolling pressure does not affect the WEL within the tested range. Finally, the mechanisms involved in WEL formation are discussed. It is suggested that the shear energy associated with deep rolling and applied along the surface grains leads to WEL formation by grain refinement.

Estudo sobre a integridade superficial do aço ABNT 4140 após a operação de torneamento

Matéria (Rio de Janeiro), 2020

RESUMO Os componentes de equipamentos estão muitas vezes sujeitos a esforços cíclicos, os quais s... more RESUMO Os componentes de equipamentos estão muitas vezes sujeitos a esforços cíclicos, os quais são capazes de provocar falhas, mesmo apenas quando deformações elásticas estão envolvidas. Os processos de fabricação são capazes de afetar a rugosidade e induzir tensões residuais de diferentes intensidades e profundidades, podendo influenciar o desempenho e a vida em serviço de peças manufaturadas. Neste trabalho, foi avaliada a influência dos parâmetros de torneamento (velocidade de corte, avanço e profundidade de usinagem) sobre a rugosidade, tensões residuais e vida em fadiga do aço ABNT 4140 temperado e revenido (40 HRC). A maior influência sobre a rugosidade foi devido à variação do avanço, que gerou maiores rugosidades para valores mais altos de avanço. Observou-se também que os parâmetros de usinagem foram capazes de alterar o perfil das tensões residuais, induzindo tensões de tração e de maior intensidade à medida que a velocidade de corte foi elevada e de tração em profundidad...

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Analysis of the surface energy interactions in the tribological behavior of ALCrN and TIAlN coatings

Tribology International, 2020

Abstract The performance of metal cutting tools is drastically affected by the presence of hard c... more Abstract The performance of metal cutting tools is drastically affected by the presence of hard coatings, which promote higher productivity and superior quality to the machined components. Nevertheless, the conventional properties are not capable to fully predict the behavior of the tool during the operation. The surface energy of solids is a characteristic which affects the contact interactions in sliding, i.e., adsorption, wetting and adhesion. However, one of the reasons why surface energy is often neglected in tribological studies is the lack of understanding concerned with the correlation between them, mainly for friction without lubricant. This work investigates the applicability of the surface energy as a property which can be associated with the performance of AlCrN and TiAlN coated materials.

Characterization of DLC coating in drilling tools

Procceedings of the 24th ABCM International Congress of Mechanical Engineering, 2017

Methods of data analysis for the ball cratering test on TiN and DLC coated steel

Materials Research, 2016

Titanium nitride (TiN) coatings are widely used in machining because of its mechanical characteri... more Titanium nitride (TiN) coatings are widely used in machining because of its mechanical characteristics which modify the surface of the substrate increasing the capacity of load support and reduction of friction, while a coating as diamond-like carbon (DLC), which also has interesting mechanical properties, needs better attention. In this sense, the development of new coatings such as DLC is as important as wear analysis techniques. This work discusses the methods available to assess abrasive wear of coatings. For this, it has been used the data of the crater volume formed in ball cratering test and compared the difference between the specific wear coefficients of substrate and coating (ks and kc). These coefficients depend of the methods used for data analyses, thus, it has been used four equations to calculate ks and kc. Moreover, profilometry (pf) has been used to calculate the volumes, and thus ks and kc. Also, the roughness of the coatings, the thickness, the images corresponding to the crater formed, the coefficient of friction, the data obtained in wear tests due to the volume removed and, in the end, a comparison between ks and kc by different methods of data analyzes are presented.

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Performance of carbide tools coated with DLC in the drilling of SAE 323 aluminum alloy

Surface and Coatings Technology, 2015

The development of new coatings in the last years contributed to the improvements of machining in... more The development of new coatings in the last years contributed to the improvements of machining industry. In general, it is known that the performance of drilling tools increases with the application of a proper coating, and it is worth remembering that the adhesion is an important condition for the success of any coating. This work presents a performance of cemented carbide cutting tool coated with diamond-like carbon (DLC). The deposition of the coating used in this study has been done using plasma enhanced chemical vapor deposition system. Suitable adhesion between film and the substrate did not occur in the initial deposition parameters tested. To enhance adhesion of the film, an intermediate silicon layer has been added. To evaluate this adhesion, VDI 3198 standard adhesion test was used. Spectra analyses collected using Raman backscattering spectroscopy have been used to characterize the composition and structural information of the film. The silicon layer was evaluated using atomic force microscopy. Drilling tests were performed using workpieces casting in aluminum alloy (SA-323) and roundness, radial deviation, deviation of diameter and roughness of geometries changes were measured as a function of the number of holes produced. The results showed that the DLC coating improves the tool performance, which subsequently improves the drilling quality.