Design Properties of Aluminium Alloys at Elevated Temperatures: Semi‐Empirical Method of Data Presentation Taking Account of Realistic Temperature Conditions

WHEN aluminium alloys are subjected to elevated temperatures their mechanical properties arc affected not only by the temperatures but also by the time of exposure. In order to illustrate the effect of such exposure the most widely adopted practice is to describe the change in properties by means of heat factors representing the ratio of property level after exposure to that obtained in the unhcated condition. Typical carpet plots of such heat factors against temperature and time are shown in fig. 1, and represent strength reductions after exposure to constant temperatures for the indicated times. Stiffness data at elevated temperatures arc usually confined to plots of elastic modulus against temperature and time and occasionally a few stress‐strain curves or tangent modulus curves for specific thermal conditions.