Study On Mechanical Behavior And Process Of Ti/Al Clad Plate In Deep Processing

Ti/Al clad plate is a typical layered metal composite material,which is widely used in aviation,metallurgy,chemical industry,high-end Kitchenware and other fields.In recent years,a lot of research work has been done on the preparation process and interface control mechanism of layered composite materials at home and abroad,and fruitful results have been achieved.Some products have achieved industrialized mass production.However,in practical applications,the bimetal layered composite sheet is usually used as a raw material,which need to be processed into various specific shapes by further processing such as punching.Due to the large difference of mechanical properties in thickness direction of laminated composite plate,metal deformation behavior and springback control during deep processing are quite different from the traditional single materials.In addition to controlling the dimensional accuracy of forming,it is necessary to take into account that the composite interface is not damaged,and the traditional forming theory is no longer applicable.With the expanding application range of layered metal composites,it is urgent to carry out research on the mechanical behavior and process of deep processing,which is of great practical significance for enriching the theory of composite forming and improving product quality.In this paper,the mechanical properties and deep processing properties of Ti/Al clad plate are studied.Considering that Ti/Al clad plate is a heterogeneous material in thickness direction,the mechanical properties and forming properties of Ti/Al clad plate are analyzed.The deformation behavior,interface separation risk and drawing process parameters of the deep drawing process of Ti/Al clad plate are studied.Number optimization.The main research contents and achievements of this paper are as follows:(1)The uniaxial tensile test and numerical simulation of Ti/Al clad plate and component metals with different layer thickness ratios show that the tensile strength,yield strength and elastic modulus of Ti/Al clad plates basically conform to the weighted average law of thickness ratio.Combined with the VIC-3D non-contact full-field strain measurement system,the deformation coordination and fracture mechanism of the Ti/Al clad plate are analyzed by comparing the local strain changes on the surface of two component materials on both sides.It is found that the longitudinal strain values of the two sides of Ti/Al clad plate are equal from elastic deformation to fracture,but the Ti side first breaks,and the transverse strain is higher than the Al side.(2)Through the rigid die bulging experiment,a Ti/Al clad plate forming limit diagram(FLD)with a total thickness of 2.1 mm and a layer thickness ratio of 26% was obtained.The interface of Ti/Al clad plate is treated by layered connection method by numerical simulation.And the numerical simulation model of the bulging process is established based on the FLD of the component materials,and the first and second principal strain data points of the element in the deformation zone after bulging of clad plate are obtained.Based on this,the FLD of the finite element model is fitted well with the measured FLD,and the finite element model and damage criterion are verified.The FLD of Ti/Al clad plate with different thickness ratios was predicted by using the established model.The results show that the thickness ratio has a great influence on the forming performance of the clad plate.With the increase of the thickness of titanium layer,the forming limit curve moves up and the forming performance improves.(3)Based on ABAQUS and the orthogonal experiment method to establish a model of cylindrical drawing deep drawing to explore the influence of four process parameters of convex die radius,convex and concave die gap,blanking gap and plate diameter on forming quality.The maximum damage,maximum thickening rate and maximum thinning rate of the forming limit diagram in the forming process are optimized.The optimal forming process is as follows: the convex corner radius is 9mm,the concave and convex mold gap is 3.25 mm,and the blanking gap is obtained.2.7mm,plate diameter 90 mm.The interface unit based on the cohesive force model is used to analyze the interface separation risk of Ti/Al clad plate during the deep drawing process.It is found that no interfacial separation occurs during the cylindrical deep drawing,and the interface damage factor at the fold is large and delamination is easy.(4)According to the process plan and the requirements of the forming parts,the matching mold is designed and the forming experiment is carried out.The result shows that the wall thickness and the drawing force-displacement curve of the formed part are consistent with the numerical simulation results,and the interface has no separation phenomenon.The maximum thinning rate and the maximum thickening rate meet the forming quality requirements.The optimization of the forming process of the Ti/Al clad plate and the accuracy of the risk analysis of the interface separation during the forming process are verified.