.7055 High-strength Aluminum Alloy Thermal Processing Of Basic Research

High strength 7055 aluminum alloy is a structure material of light weight used in the area of aviation and spaceflight. The homogenization process and hot machining process of the ingot is the key technology of this alloy, the property of the hot rolling plate is also the center of people' attention. In this work, the laws of microstructure and property evolution of 7055 alloy on the as-cast, different homogenization treatment and hot rolling conditions have been studied using the analysis method of room temperature tensile test, hardness and conductivity test, OM observation, SEM, TEM and XRD. The relation between stress and strain of the alloy on the different hot machining parameter conditions has been investigated by thermol-simulation technology, the purpose is to provide conferences for stipulating for the hot machining process. The conclusions can be summarized as follows:1.The ingot of 7055 alloy shows apparently dendrite segregation phenomena. During the course of homogenization, the variety of microstructure shows in two sides: on the one side, the dendrite structure and coarse equilibrium phases between dendrites of super saturation solution disappear gradually as the homogenization temperature increase and the homogenization time prolong; on the other hand, when the alloy was homogenized under the temperature of 400 ℃, the super saturation solution decompounded and separated out equilibrium n (MgZn2) and S(Al2CuMg) phases, when the alloy was homogenized on the temperature of high than 400癈, the equilibrium phases re-dissolved into the solution matrix. The suitable homogenization treatment process is 450℃/24h.2. The flow stress of 7055 alloy under high temperature compress deformation is controlled by both deforming temperature and strain rate, the flow stress decreases with the increase of deforming temperature, while increase with the increase of strain rate. Under the deformation condition, the relation of the flow stress, strain rate and the deformation temperature is showed as follows:3. When 7055 alloy is deformed on the temperature of less than 450℃, the hot deformation structure is mainly dynamic recovery structure. When 7055 alloy is deformed on the temperature of more than 450℃, a few recrystalizaion structure can be observed in the hot deformation structure. The favorable hot processing temperature is approximately 400℃.4. The main texture of the hot rolling plate of 7055 alloy is {110}<112>.The properties of the hot rolling plate of 7055 alloy in different direction is different (anisotropy),the strength is the highest and the elongation is relatively low in rolling direction, as the tropism angle with the rolling direction increase, the strength decrease gradually and the strength decrease 16% in the long-transverse direction than in the rolling direction. But the elongation is different, as the tropism angle with the rolling direction increase, the elongation increases firstly and then decreases, when the tropism angle is 60?, the elongation is the highest and is double more than the elongation in rolling and transverse directions.