DETERMINATION OF CONSTANTS OF CONSTITUTIVE HOT WORKING EQUATIONS AND PRODUCTION OF ISOTHERMAL σXε CURVES FOR Al-Li ALLOYS

摘要

In the present paper a method for determining the constants of constitutive hot working equations is described. The experimental data used were obtained by plane strain compression tests for several different conditions of temperature and strain rate during testing, for both 8090 and 8091 alloys. After determination of the constants by means of a simple and straightforward method it became possible to convert non-isothermal data to isothermal stress values as a function of strain for all tests done. Such procedure allows for the production of true stress versus true strain curves (σxε curves), which are valid for iso-Z conditions, i.e., conditions of constant temperature and strain rate. The results obtained are very important due to their applicability in predicting stress, as well as microstructural features, developed during hot working of both alloys.