Mechanical Spectra of an Al-12.7Si-0.7Mg Alloy under Extrusion and T6 States

Mechanical spectra of an Al-12.7Si-0.7Mg alloy under extrusion and the solid solution treatment followed artificial aging (T6) states were measured at different frequencies. It has been found that their spectra present differences. There was an obvious internal friction peak near to 200°C with increasing the temperature. The value of internal friction presented increase started from 300°Cand height of the peak was low, there existed a peak near to 270°C during the cooling processes in the spectrum for the extrusion state. For the T6 state alloy, no peaks could be observed during the heating processes. With decreasing the temperature, the internal friction peaks were again observed near 200°C and 270°C.