Microstructure and Mechanical Properties of Aluminum 7050 Alloy Sheet in Hot Stamping-Quenching Integrated Process with Cold Dies

In this study, cold dies were proposed to use in hot stamping-quenching integrated process which aimed to improve the formability and avoid thermal distortion for a heat-treatable Aluminum 7050 alloy during hot-stamping. During this hot stamping-quenching integrated process, influences of initial base metal temper and heat treatment schedule after hot stamping on the microstructure and mechanical properties were investigated systematically. Two initial base metal tempers were applied in AA7050 alloy, over-aged T7 and natural-aged T4. The temperature of hot stamping was 450 degrees C, meanwhile, the strain rate was 1x10(-1)s(-1). Both traditional and novel heat treatment schedules after hot-stamping were used in order to discuss the effects of heat treatment processing parameters on the microstructure and mechanical properties. The microstructure was analyzed by optical microscope (OM) and transmission electron microscope (TEM), and the mechanical properties were measured by Vickers hardness and tensile tests. The correlation between the schedules, microstructure and mechanical properties of the Al alloys were discussed as well.