Analysis of Compression Creep Deformation of 7050 Aluminum Large Scale Open Die Forgings during the Solution Heat Treatment Process

Acknowledgments We would first like to acknowledge everyone who helped us complete our senior project. Professor Blair London, our senior project advisor, for giving us guidance throughout the year. Kyle Logan for meeting with us weekly to assist in our progress and guide us through problems and Mark Timko for offering advice with certain obstacles, both who were our sponsors from Weber Metals. Luka Dugandzic for helping us design and manufacture the fixture we used for testing. Professor Hans Mayer working with us weekly to test our samples using the profilometer. Finally, Professor Rod Hoadley for allowing us to use the lathes during his labs to prepare our samples. All of the before mentioned went out of their way to help us and we greatly appreciated it. ii Abstract A stress, ranging from 104.17 to 166.67 psi, was applied to 0.5 in diameter cylindrical samples of 7050 aluminum using a manufactured fixture that applies stress using an indenter with a diameter of 0.127 in. The stress range used replicates the stresses produced on large scale forgings weighing up to 4000 lbs. We chose a maximum, medium and low stress as our stress parameters. The samples were placed into the fixture for stability then placed in a furnace heated to 890°F which is the solution heat treatment temperature for 7050 aluminum. The heat treatment times varied between 4 and 24 hours. The creep deformation produced from the different parameters of time and stress was analyzed using a profilometer. The amount of deformation for each sample was in the range of 0.001 to 0.007 in. These results coincide with the large scale with a difference of about 1896 to 1. The amount of deformation and time was plotted to generate creep curves for the various stresses produced. The creep curves can then be used to develop the conditions when the large scale forgings would experience creep deformation and therefore be able to prevent the deformation in the future.