Effect of Heat Treatment Parameters on Properties of Al–4.8Si–1.2Cu–0.5Mg Alloy

Abstract

The effects of heat treatment parameters including solid solution temperature, transfer time, delay time, aging temperature and time on mechanical properties and electrical conductivity of Al–4.8Si–1.2Cu–0.5Mg alloy were studied by independently altering variables. The experimental results showed that with the increase of solid solution temperature, the tensile strength gradually increases, and the elongation and electrical conductivity monotonously decrease. There is a little effect on the mechanical properties and electrical conductivity when the transfer time is less than 40 s. As the delay time increases, the tensile strength decreases quickly and then increases continuously while the elongation and electrical conductivity increases rapidly and then decreases gradually. The effects of aging temperature and time on the tensile strength and elongation have the same tendency. The electrical conductivity always decreases with the aging temperature while it presents an upward-downward-upward change with the aging time. When the solid solution temperature is 525°C, the transfer time and delay time are below 20 s and 2 h, and aging temperature and time are 160°C and 3–5 h, the alloy can achieved satisfactory properties.

Fig. 1 Solid solution temperature dependence of tensile strength, elongation and electrical conductivity after experiment scheme No. 1 in Table 1.