Mechanical properties and micro-structural of Al-Zn-Mg-Cu alloy by semi-solid SIMA processed

This paper investigates the microstructure and mechanical behavior of 7050 aluminum alloy during semi-solid process. The semi-solid process involves multi-directional forging at 300℃, and followed by semi-solid treatment at 590℃-630℃ for 10-30 min. The microstructure was characterized by scanning electron microscopy, X-ray diffraction, electron back scattered diffraction and transmission electron microscopy. There are many copper enriched at grain boundaries during isothermal treatment. It also can be seen that the reduce of Mg, Zn and Cu are inside the grain clearly. The mechanical properties of different treated samples in semi-solid state were studied by tensile test. The results show that the tensile strength and yield strength of the material decrease with the increase of holding time and due to its internal solid-liquid changes.