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This study aimed to evaluate the resistance of a Ti-6Al-4V alloy in creep after heat treatments. It was used a Ti-6Al-4V alloy in cylindrical bars forms, forged condition and annealing at 190 °C for 6 hours and cooled in air. The microstructure Ti-6Al-4V alloy was evaluated after heat treatment and was submitted to creep tests at 600 °C and stress conditions from 125 to 319 MPa at constant load. Samples preparation for optical microscopy and scanning electron microscopy followed the usual methods of metallography. Three different conditions of heat treatments were utilized to obtain the following microstructures: Widmanstätten, Martensite and Bimodal. The alloy with Widmanstätten structure shows greater resistance to creep with a longer life time in creep.

This work intends to analyze the influence of the stress and temperatures used in creep mechanical tests in the types of fractures that occurred in the superalloy Inconel 718. For this, the superalloy was subjected to creep tests under the conditions 625 to 814 MPa at temperatures of 650, 675 and 700°C. After the tests, the fractured samples were cleaned on an ultrasound and subjected to microstructural analysis using the technique of scanning electron microscopy. Images were performed with different increases in order to analyze the type of fracture that occurred in the material. The elongated sample and its reduction in area were also measured in order to study the effects of different conditions used in the creep tests under material's fracture.