Warm compression tests of aluminum alloy

Compression tests of aluminum alloy were experimentally investigated at specified temperatures ranging from 30 ‡C (room temperature) to 250 ‡C under a constant strain rate of 0.2 X 10^-3/s using powdered graphite as a lubricant throughout the tests. The effective stress method is found to show a significant fall in stress values beyond the barreling point, indicating a serious shortcoming over the barrel correction factor method within the tested temperature range. The compression curves obtained using the barrel correction factor method and the Bridgman remachining technique (no barreling allowed during the test) are found to have close values, even at higher temperatures. The true-stress versus true-strain curves and the barrel sizes obtained follow empirical power laws, even at higher test temperatures.