Temperature dependence of the elastic modulus of commercial aluminum cast alloys

The modulns of longitudinal elasticity and their temperature dependence in commercial aluminum cast alloys were measured in the temperature range from room temperature (20°C) to 250°C by the resonant frequency method. The results obtained are as follows: The modulus of longitudinal elasticity tended to decrease weakly and linearly (the tangent of its decrease, m = (-2.4--3.3) × 102kg/cm2/°C) with the rise of temperature. Within the range of the experiments, aluminum cast alloys were divided into 3 groups, the lst group materials having large moduli of elasticity E0 at room temperature (i. e., E0 = (7.15-7.25) × 105kg/cm2) were AC2A-T6, AC3A-F, AC4A-F, AC4A-T4, AC4B-F, AC4B-T4, AC8A-F, AC8A-T4, etc., the 2nd group materials having intermediate moduli (i. e., E0 = (6.85-6.98) × 105kg/cm2) were AC4C-F, AC4C-T5, AC4C-T6, AC4D-F, AC4D-T6, AC7A-F, etc. and the 3rd group materials showing considerably smaller moduli (i. e., E0 = (6.58-6.65) × 105kg/cm2) were AC1A-F, AC1A-T6, AC2A-F, etc. However, there were some differences between the moduli in this experiments and the moduli in the other data books, and these were considered due to the difference of the measurement principles and of hypotheses or assumptions involved in these principles, so it is suggested that the moduli of elasticity should be reported with indication of the measuring method.