Effect of Quench Process on Mechanical Properties and Conductivity of 7475 Alloy

By using the mechanical property tester, conductivity tester, DSC and optical microscope, the effects of the solid solution temperature, water temperature, transfer time and delay time of quenching on the mechanical properties and conductivity of 7475 alloy were investigated, respectively. The results showed that all properties are satisfied at the solid solution temperature of 460 degrees C-480 degrees C while the over-burning may occur above 490 degrees C. The tensile strength, yield strength and elongation are changed about -6.5 MPa, -6.2 MPa and 0.17% when the water temperature is increased by 10 degrees C, but the conductivity always remains about 37.6%IACS from 30 degrees C to 60 degrees C. The strengths and conductivity will drop while the elongation will gradually rise against the transfer time. With the extension of delay time, the strengths decrease and then increase while the elongation and conductivity has a reverse change. When the delay time is 8 h, the tensile strength and yield strength achieve the minimum of 512 MPa and 450 MPa, and the elongation and conductivity reaches the maximum of 17.8% and 37.4%IACS. The optimal quench parameters are that the solid solution is 470 degrees C, water temperature is below 60 degrees C, transfer time is below 30 s, and delay time is below 4 h or above 24 h.