Made available in DSpace on 2014-12-17T14:58:03Z (GMT). No. of bitstreams: 1 ErikaCCL_DISSERT_1-65.pdf: 4712655 bytes, checksum: a7d827be13ca2b8a6228ba742c487da6 (MD5) Previous issue date: 2010-12-21 / We developed an assay methodology that considered the temperature variation and the scanning electron microscopy as a method to quantify and characterize respectively the consumption evolution in three 46 LA machines, with internal combustion and two-stroke engines, 7.64 cm3 cylinder capacity, 23.0 millimeters diameter and 18.4 millimeters course, RPM service from 2.000 to 16.000 rpm, 1.2 HP power, and 272 grams weight. The investigated engines components were: (1) head of the engine (Al-Si alloy), (2) piston (Al-Si alloy) and (3) piston pin (AISI 52100 steel). The assays were carried out on a desktop; engines 1 and 2 were assayed with no load, whereas in two assays of engine 3 we added a fan with wind speed that varied from 8.10 m/s to 11.92 m/s, in order to identify and compare the engine dynamic behavior as related to the engines assayed with no load. The temperatures of the engine s surface and surroundings were measured by two type K thermopairs connected to the assay device and registered in a microcomputer with data recording and parameters control and monitoring software, throughout the assays. The consumed surface of the components was analyzed by scanning electron microscopy (SEM) and microanalysis-EDS. The study was complemented with shape deformation and mass measurement assays. The temperature variation was associated with the oxides morphology and the consumption mechanisms were discussed based on the relation between the thermal mechanical effects and the responses of the materials characterization / Foi desenvolvida uma metodologia de ensaio que considerou a varia??o da temperatura e a microscopia eletr?nica de varredura um m?todo de quantificar e qualificar respectivamente a evolu??o do desgaste em tr?s m?quinas 46 LA de motor de combust?o interna de dois cursos, com uma capacidade de cilindro de 7,64 cm3, de 23,0 mil?metros de di?metro e de curso de 18.4 mil?metros, RPM de servi?o de 2.000 a 16.000 rpm, pot?ncia de 1,2 HP, peso de 272 gramas. Os componentes do motor investigados foram: (1) cabe?a do motor (liga Al-Si), (2) pist?o (liga Al-Si) e (3) pino do pist?o (A?o AISI 52100). Os ensaios foram realizados em uma bancada, os motores 1 e 2 foram ensaiados sem carga, e o motor 3 foi adicionado a dois ensaios um ventilador com velocidade do vento que variava entre 8,10 m/s a 11,92 m/s, com a finalidade de identificar e comparar o comportamento din?mico do motor com os motores ensaiados sem carregamento. As temperaturas pr?xima ao contato e ambiente foram medidas atrav?s de dois termopares tipo K conectados ao dispositivo de ensaio e registradas por um microcomputador com software de aquisi??o de dados, controle e monitoramento dos par?metros durante os ensaios. A superf?cie desgastada dos componentes foi analisada por microscopia eletr?nica de varredura (MEV) e microan?lise-EDS. O estudo foi complementado por ensaios de desvio de forma e medi??o de massa. A varia??o de temperatura associou-se ? morfologia dos ?xidos e os mecanismos de desgastes evidenciados foram discutidos correlacionando-se a solicita??o termomec?nica ?s respostas da caracteriza??o dos materiais