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Master's Dissertation
DOI
10.11606/D.85.2018.tde-09082018-092107
Document
Author
Full name
Alexandre Vieira
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2018
Supervisor
Committee
Rossi, Wagner de (President)
Batalha, Gilmar Ferreira
Gonçalves, Marcelo
Title in Portuguese
Análise e estudo de parâmetros para texturização a laser com pulsos ultracurtos para melhoria das propriedades tribológicas de componentes de motor
Keywords in Portuguese
aço SAE 5115
laser de pulsos ultracurtos
texturização a laser
tribologia
usinagem a laser
Abstract in Portuguese
Neste trabalho foram realizadas otimizações no processo de fabricação de micro cavidades na superfície do aço DIN 16MnCr5, com o objetivo de reduzir o coeficiente de atrito dinâmico entre duas superfícies. Para a confecção das micro cavidades (dimples) foi utilizado um laser com pulsos ultracurtos, de largura temporal de algumas dezenas de femtossegundos. Além de estudos de variação de fluência do laser, também foi analisado o resultado da utilização de diferentes perfis de energia do feixe. Para a caracterização das micro cavidades, foram utilizadas técnicas como a microscopia eletrônica de varredura, para análise morfológica, interferometria de luz branca e microscopia confocal para análise topográfica, dimensional e perfilométrica. Foram realizados ensaios de desgaste, em tribômetro para análise da variação do coeficiente de atrito após a texturização. Após os ensaios, percebeu-se que a texturização com pulsos ultracurtos apresenta grande vantagem na confecção de micro cavidades devido a precisão e ausência de interação térmica entre o laser e o material. Em relação ao atrito, as amostras texturizadas apresentaram redução da força e do coeficiente de atrito, porém, foram observados sinais de aumento da pressão de contato entre as superfícies.
Title in English
Analysis and study of parameters for laser surface texturing with ultrashort pulses to improve of tribological properties of engine components
Keywords in English
laser machining
laser surface texturing
SAE 5115 steel
tribology
ultrashort laser pulses
Abstract in English
In this work, optimizations were realized in the dimples manufacturing process on DIN 16MnCr5 steel surface, the target were to reduce the coefficient of dynamic friction between two surfaces. A laser with ultrashort pulses, temporal width of a few tens of femtoseconds, was used to manufacture dimples. In addition to studies of variation of laser beam fluency, the results of the use of different beam energy profiles were also analyzed. For analysis of dimples, techniques such as scanning electron microscopy (SEM), for morphological analysis, white light interferometry and confocal surface microscopy were used for topographic, dimensional and perfilometry. Wear tests were performed to analyze the variation of the friction coefficient in texturing surface. After the tests, it was observed that the texturing with ultrashort pulses presents a great advantage in manufacturing of dimples, due to the precision and absence of thermal interaction between the laser beam and the material. In relation to the friction coefficient, the textured samples presented a reduction of the friction force and consequently of the friction coefficient, but an increase in the contact pressure between the studied surfaces was observed.
 
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2018VieiraAnalise.pdf (3.77 Mbytes)
Publishing Date
2018-09-19
 
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