SPF/DB Processing Of Hollow Double-layer Structure For 5A90 Al-Li Alloy

5A90 Al-Li alloy compared with composite materials with similar weight advantage, but it is easier to secondary processing and forming. Add lithium element, alloy has obvious improvement in specific strength and specific stiffness. This article mainly studied superplasticity and diffusion bonding properties of 5A90 Al-Li alloy, and on the basis study the hollow double layer structure of the SPF/DB process Experimental.Under the condition of different deformation temperature and strain rate o, high temperature tensile test was carried out on the 5A90 Al-Li alloy, analysis of various process parameters on metal flow stress, strain and elongation, etc, get the best deformation temperature is 400 oC, strain rate is 0.001 s-1, the elongation is 243.97%, and in experimental parameters range within of this frame equation.Follow the principle of orthogonal design, to study diffusion bonding performance of 5A90 Al-Li alloy, analysis bonding temperature, holding time and surface roughness on the quality of the diffusion bonding joints. Results show that, when the connection temperature is 540 oC, holding time is 2.5h, the surface roughness is 800 #, diffusion bonding joint with better bonding rate, around 99%, joint shear test shows that fractures are concentrated in the parent metal, maximum joint shear strength can reach 143 MPa, and joint tissue and base metal was basically the same.According to the results of tensile test, using MARC finite element simulation hollow double-layer structure superplastic forming process, determine the optimum strain rate of processing for 1×10-3s-1, under the strain rate, double-layer structure distribution thickness is relatively, and needed less time for forming. Depending on thickness distribution can reverse the time-pressure load curve in the processing, and provides guidance for the follow-up process.According to the basic performance testing and finite element simulation of plate, determining parameters of forming process parameters, development process, use a combination of SPF/DB forming process obtained good quality of 5A90 Al-Li alloy hollow double-layer structure. Finally, analysis structure pieces wall thick, diffusion bonding quality, can found structure pieces wall thick distribution uniform, has slightly reduction thin of phenomenon, reduction thin most obviously of parts for mold concave die round angle at, reduction thin to 0.80 mm around, connection interface at basic not exists empty, welding collection rate than high, structure pieces grain long trend not obviously.