Research on Properties of RE-7075 Al Alloy′s Hot Rolled

Abstract

The RE-7075 Al alloy′s hot rolled sheet was studied in this experiment.The microstructure,over-burning temperature,fracture surface and phase were analyzed by modern materials analytical instruments which include OM(optical microscope),DSC(differential scanning calorimetry), SEM(scanning electron microscope) and XRD(X-ray diffraction),respectively. The results show that there are needle-like or rod-like grains in the SL direction and the fibrous or streamlined grains in the LT direction of hot rolled sheet′s microstructure;The microstructure takes place the phenomenon of over-burning when rolling temperature beyond 480°C; These sheets manifest mainly brittle fracture under the tensile stress; The primary phase of microstructure contain α(Al)、AlLa4、Al2Zn3、AlMgZnCuLa、LaMgZn、AlMg4Zn11 . In recent years,people continued to study the rare earth (RE) and add the RE to the conventional aluminum alloy.So the RE became a hot research because it can improve the properties of materials. The RE-7075 Al alloy is one of the categories and can be widely used as the structural materials of aerospace and weapons industry.With aerospace and the war industry enterprise rapid development in our country, the quantity demand is getting bigger and bigger[1-2].Therefore,it is urgent for us to study a high strength-toughness aluminum alloy material.The aim of RE-7075 Al alloy′s hot rolled sheet was researched in this experiment.The microstructure, over-burning temperature,the fracture mode and phase composition of the sheet were indepth analysised under the rolling process. So these can provide a theoretical basis of the hot rolling process development of science.