The Analysis On Slip Deformation And Damage Behavior Of Fcc Metals Based On Crystal Plasticity Finite Element Model

In our daily life and productivity,face center crystal(FCC)metals make a largely proportion.The mechanical properties of metal materials is closely related to their anisotropy and micro-structure,especially in the engineering area.As one of FCC metals,copper has widely used in the world.Ultra-fine copper wide application prospect can greatly improve the strength of copper.Slip deformation is the most major plasticity behavior of FCC metals.So far,researchers have developed various plasticity models to describe and predict the mechanical properties of metal materials,but each has its own priorities.In this paper,based on the theory of crystal plasticity,a geometrical method is used to describe the slip line on the surface of materials after slip deformation,and the slip rotation of the crystal is described under the constitutive model.And then the damage variate is quoted into the crystal plasticity constitutive model to describe the damage behavior as the plasticity deformation accumulates to a degree,and then the crack initiation life time of ultra-fine copper with an initial defect is calculated and predicted.The main points are as follows:1.Use the Lagrange interpolation to calculate the damage variable,which has greatly improved the computation speed and the astringency and stability of the program.2.We have developed a geometrical method to describe the slip line on the surface of a single crystal copper after uniaxial load.The geometrical method can directly describe the slip line which on the surface of FCC metals appears 4 clusters.And we elementary explored the rotation law of FCC metals from the point of Slip face.3.Based on crystal plasticity,we have deeply explored the rule of crystal rotation,and reasonable explanations have also given.And we discover that the magnitude of grain rotation strongly depends on the initial lattice orientation of the grain.Furthermore,a reasonable explanation is given for the distribution of grain rotation magnitudes in the point of Schimd factor.4.A damage variate is quoted into the crystal plasticity constitutive equation,based on which,we simulate the damage evolution during the uniaxial deformation when plastic deformation accumulate to a degree,furthermore,the ductile damage behavior of ultra-fine copper with an initial defect,and the necking behavior of ultra-fine copper is also simulated based on the crystal plasticity damage model.5.Crystal plasticity damage model is used to describe the necking behavior of ultra-fine copper and the influence of the crack initiation lifetime by the size of initial defect.And reasonable explanations have also given.