Effect of loading rate on absorbed energy and fracture surface area in wrought aluminum alloys

The effect of loading rate on absorbed energy and fracture surface area of three types of wrought aluminum alloys, namely high toughness 5083-O and 6061-T651 alloys and low toughness 7075-T6 alloy are studied. A laser displacement measuring equipment and a scanning laser microscope are used in order to measure three-dimensional geometry of the fracture surface. Shear lip and plastic hinge can be observed in 5083-O and 6061-T651 aluminum alloys. According to a measuring region, the calibration factor K is notably different. Moreover, the calibrated fracture surface area of each fracture geometry changes considerably with increasing loading rate. On the other hand, in 7075-T6 aluminum alloy, macroscopic fracture geometries are not clearly defined, and almost no difference appears in the calibration factor K within the same fracture surface. Moreover, calibrated whole surface area increases linearly with increasing loading rate. In any aluminum alloys, the tends in the loading rate change of calibrated whole fracture surface area, AW, and the total absorbed energy, Et , with loading rate are similar each other. Therefore, the change of fracture surface area is one of the main factors that affect the change of absorbed energy.