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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.

The study of creep has a major importance when materials are submitted to high stress and homologous temperature. Superalloys are designed to operate under high stress, temperature and corrosion environment. Those properties of superalloys are due to high temperature stable matrix, solid solution elements and precipitated particles. This study aims to determine the creep resistance of Inconel 718 aged superalloy obtained through the tests according to ASTM E139-06, at stress range of 510 to 700 MPa and temperature of 675°C. The parameters as the primary creep time (tp), steady-state creep rate (εs), time to rupture (tr) and strain to rupture (εr) are important to evaluate the creep resistance. It used a scanning electron microscope (SEM) to obtain images of the fracture surface of specimens. The images of the fracture surface were investigated in order to relate the temperature of test with the fracture mechanism.