The Finite Element Simulation And Investigation Of Micr-structure And Mechanical Properties Of The Pure Aluminum By Equal Channel Angular Extrusion

The parameters,change and their affecting factors during ECAE process have been researched using finite element modeling and experiments techniques. A simulation software (MSC?Marc) has been used to study the change and effect of the various parameter during ECAE;The effects of ECAE on microstructures and properties of pure aluminum are studied in this paper. We also discussed the refinement mechanism during ECAE on the basis of experiment and analysis.The results of the simulation show that the outer angle affects the uniformity of the strain,the area of the corner increases gradually, and the deformation mechanism transform from the pure shear deformation into the composite of the shear and bending deformation with the increase of the outer angle, the proper angle is equal to 100～300. the channel angle affects the value of the strain,the area of the corner keep identical nearly, and the deformation mechanism transform from the pure shear deformation into bending deformation with the increase of the channel angle, the proper angle is equal to 900～1200. The friction affects the uniformity and the value of the strain, the area of deformation zone and the load increases gradually with the increase of the frictional factor, the proper parameter is equal toμ=0.1～0.3.Meanwhile the observation of the microstructures indicates that the ECAE technique can refine the microstructure effectively. With the increasing of equivalent strain, the original grain, which is large and gross, is refined to a large extent. The average grain size is 1.2μm ,while the original grain size is 50μm .The results show that the mechanical properties of Al are changed with the change of its microstructure seriously. The Brinell hardness increases remarkably for X,Y,Z plane in different deformation zone,The yield strength increases from 81.6MPa in the original state to 116MPa after 4 passes by ECAE,and the tensile strength increases from 96MPa to 119MPa too,the elongation keeps above 24%,the Fracture mechanism presents typical intergranular fracture,and the cracks are composed of surface crack and embedded crack。The X–ray diffraction (XRD) pictures of fabricating Al samples show that diffraction intensity of the main crystal plane changed in a largest extent after extrusion once; it means that there is texture in the sample being extruded once because of the refinement of grains and the increased micro-strain.