BS in Materials Engineering
Materials Engineering Department
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.