Study on microstructure and mechanical properties of 7075 aluminum alloys by ultrasonic hot-pressing sintering

To solve the problems of coarse grains, pores, low relative density, and poor mechanical properties of traditional hot-pressed sintered 7075 aluminum alloys, the 7075 aluminum alloys were prepared by ultrasonic hot-pressing sintering technology, and the influence of sintering temperature (450, 475, 500, 525 ℃) on the microstructure and mechanical properties of aluminum alloys was studied. The results show that with the increase of sintering temperature, the relative density, yield strength, tensile strength, and elongation of the aluminum alloys all increase first and then decrease. When the sintering temperature is 500 ℃, the aluminum alloys have the large and deep dimples, small grain size, and the best mechanical properties, the relative density is (99.99±0.01)%, the yield strength is (153±5) MPa, the tensile strength is (245±10) MPa, and the elongation is (6.78±0.29)%, which is increased by 1.09%, 15.90%, 10.86%, and 60.28%, respectively, compared with the non-ultrasonic hot-pressing sintering.