Crystal Plasticity Simulation Of Hexagonal Metal Layered Composites Under Deformation

Hexagonal metal materials have the characteristics of high specific strength and stiffness,good electrical and thermal conductivity,etc.In recent years,the multi-layer layered metal composites,which are made of a hexagonal metal and other metals,are attracted to the attention of the people.Metal layered composites often bear the effect of large strain deformation,which put forward higher requirements for mechanical properties.In order to better design and develop hexagonal metal composites with high strength and toughness and provide theoretical guidance for the safe service of the materials,it is of great significance to simulate the internal plastic deformation mechanism of metal layered composites.In this paper,the material parameters of pure Ti were determined by crystal plastic finite element simulation.The influence of key parameters on the mechanical behavior of pure Ti was analyzed.On this basis,the plastic deformation mechanism of Copper and Goss oriented pure Cu and(1010)[2110],(1120)[0001],(1120)[1010],(0l13)[2110]and no preferred oriented pure Ti were simulated.Ten kinds of Cu/Ti metal layered composites composed of them were also simulated in this paper.The equivalent true stress-true strain curves,the status of deformation system,the shear ratio of the shear band system,the distribution of equivalent true stress and crystal rotation angles were analyzed.The microscopic deformation mechanism of the metal lamellar composites was clarified.Besides,the difference of plastic deformation mechanism between Cu/Ti metal layered composites and single phase pure Ti and pure Cu composites were discussed.The effect of initial orientation on the plastic deformation mechanism of pure Ti and pure Cu was discussed.The effect of initial orientation on the plastic deformation mechanism of Cu phase and Ti phase for Cu/Ti metal layered composites were analyzed.The main conclusions are as follows:The plastic deformation mechanism of pure Ti and pure Cu is greatly dependent on the initial crystal orientation.In(0l13)[2110]and no preferred oriented pure Ti and Copper oriented pure Ti the starting of the shear band system can be identified under the plane strain compressive load.But it can't recognized in(1010)[2110]?(1120)[T010]and(1120)[0001]oriented pure Ti and Goss oriented pure Cu.When the reduction rate of Copper oriented pure Cu plane strain compression load was 20%,the shear band had penetrated through the whole material and the strain concentration begins to appear at the phase interface.When the reduction rate was 40%,the strain concentration had penetrated through the whole material and a large angle crystal rotation had taken place in the shear band region.With the increase of reduction rate,more shear band deformation mechanism started.The strain concentration in the band is caused by the operation of the shear band system,which is the root cause of the large angles rotation of the crystal.The equivalent true stress in the Cu/Ti layered composite of various orientations exhibited non-uniform distribution.In order to coordinate the strain between two phases in the material,the equivalent true stress of the Cu phase was much smaller than that of the Ti phase.The initial orientation of Cu phase has an important influence on the deformation mechanism of the adjacent Ti phase.When Ti phase was(1010)[2110]orientation and Cu phase was Copper orientation,the equivalent true stress and the equivalent true strain distribution in the Ti phase were not uniform.Ti phase had large crystal rotation angles.The phase interfaces were slightly inclined.When Cu phase was Goss orientation,the equivalent true stress and the equivalent true strain distribution in the Ti phase were uniform.No large angle crystal rotation was observed.The phase interfaces were straight.The same conclusion can be obtained when Ti was(0113)[2110]orientation.The initial orientation of Ti phase also has an important influence on the deformation mechanism of the adjacent Cu phase.When Cu phase was Goss orientation and Ti phase was(1120)[0001]orientation,the equivalent true strain and equivalent true stress in Cu phase were uniform.The shear band system was not recognized.When Ti phase was(0113)[2110]orientation or has no preferred orientation,the shear band system can be activated.Ti phase was necked and the significant strain concentration can be extended into Cu phase.