Shear Plastic Deformation Behavior Research Articles

Finite Element Modelling of Copper by Equal Channel Angular Extrusion

Equal channel angular extrusion (ECAE) is a severe plastic deformation (SPD) method for obtaining bulk nanostructured materials. The ECAE die consists of two equal channels that intersect at an angle, usually between 90o and 135o. . In the present study, the plastic deformation behavior of copper during the ECAE process with 120o die was investigated. To analyze the deformation behavior and the related strain distributions in the specimen, the commercial FE code ABAQUS has been used. The properties of the materials are strongly dependent on the shear plastic deformation behavior during equal channel angular extrusion (ECAE), which is controlled mainly by die geometry, material properties, and the friction between billet and the die. The ECAE process for these conditions was explained using the two different friction conditions of 0.15 and 0.08 to all sliding surfaces. The effective strain by the theoretical equation is in good agreement with the FEM results.

An Investigation into Optimized Ti-6Al-4V Titanium Alloy Equal Channel Angular Extrusion Process

The shear plastic deformation behavior of a material during equal channel angular (ECA) extrusion is governed primarily by the die geometry, the material properties, and the process conditions. This paper employs the rigid-plastic finite element (FE) to investigate the plastic deformation behavior of Ti-6Al-4V titanium alloy during ECA extrusion processing. Under various ECA extrusion conditions, the FE analysis investigates the damage factor distribution, the effective stress-strain distribution, and the die load at the exit. The relative influences of the internal angle between the two die channels, the friction factors, the titanium alloy temperature and the strain rate of billet are systematically examined. In addition, the Taguchi method is employed to optimize the ECA process parameters. The simulation results confirm the effectiveness of this robust design methodology in optimizing the ECA processing of the current Ti-6Al-4V titanium alloy.

Design Analysis of TMJ Implant under Physiological Loading Condition

Equal channel angular extrusion (ECAE) is a severe plastic deformation (SPD) method for obtaining bulk nanostructured materials. The ECAE die consists of two equal channels that intersect at an angle, usually between 90。and 135。. In the present study, the plastic deformation behavior of copper during the ECAE process with 120o die was investigated. To analyze the deformation behavior and the related strain distributions in the specimen, the commercial FE code ABAQUS has been used. The properties of the materials are strongly dependent on the shear plastic deformation behavior during equal channel angular extrusion (ECAE), which is controlled mainly by die geometry, material properties, and the friction between billet and the die. The ECAE process for these conditions was explained using the two different friction conditions of 0.15 and 0.08 to all sliding surfaces. The effective strain by the theoretical equation is in good agreement with the FEM results.

A Finite Element Investigation into the Changing Channel Angular Extrusion of Brass Alloy

This study investigates a novel changing channel angular (CCA) extrusion process, in which high strains are induced within the billet by passing it through a series of channels of unequal cross-sections arranged such that they form specified internal angles. Using commercial DEFORMTM 2D rigid-plastic finite element code, the plastic deformation behavior of CuZn37 brass alloy is examined during one-turn and two-turn CCA extrusion processing in dies with internal angles of φ =90o, 120o, 135o or 150o, respectively. The simulations focus specifically on the effects of the processing conditions on the effective strain, the rotation angle and the effective stress induced within the extruded billet. The numerical results provide valuable insights into the shear plastic deformation behavior of CuZn37 brass alloy during the CCA extrusion process.

Investigation into equal channel angular extrusion process of billet with internal defects

The shear plastic deformation behavior of a material during equal channel angular (ECA) extrusion is governed primarily by the die geometry, the material properties, and the process conditions. This study uses the commercial DEFORM™ 2D (two-dimensional) rigid-plastic finite element code to investigate the plastic deformation behavior of materials with internal defective voids during 1- and 2-turn ECA extrusion processing. The present simulations investigate the damage factor distributions, the total velocity distributions, the rotation angle distributions, the void dimension, and the stress–strain distributions around the defective voids under various extrusion conditions. The mesh element increase of the billet mesh in the 2-turn ECA extrusion process is also investigated. The present numerical results provide valuable insights into the shear plastic deformation behavior of materials containing defective voids in the ECA extrusion process.

Study of the Titanium Alloy Deformation Behavior in Equal Channel Angular Extrusion

The shear plastic deformation behavior of a material during equal channel angular (ECA) extrusion is governed primarily by the die geometry, the material properties, and the processing conditions. Using commercial DEFORMTM 2D rigid-plastic finite element code, this study investigates the plastic deformation behavior of Ti-6Al-4V titanium alloy during 1- and 2-turn ECA extrusion processing in dies containing right-angle turns. The simulations investigate the distributions of the billet mesh, effective stress and effective strain under various processing conditions. The respective influences of the channel curvatures in the inner and outer regions of the channel corner are systematically examined. The numerical results provide valuable insights into the shear plastic deformation behavior of Ti-6Al-4V titanium alloy during ECA extrusion.

ECAP 공정을 이용한 분말의 치밀화

In recent years, equal channel angular pressing (ECAP) has been the subject of intensive study due to its capability of producing fully dense samples having a ultrafine grain size. In this paper, the ECAP process was applied to metallic powders in order to achieve both powder consolidation and grain refinement. In the ECAP process for solid and powder metals, knowledge of the internal stress, strain and strain rate distribution is fundamental to the determination of the optimum process conditions for a given material. The properties of the ECAP processed solid and powder materials are strongly dependent on the shear plastic deformation behavior during ECAP, which is controlled mainly by die geometry, material properties, and process conditions. In this study, we investigated the consolidation, plastic deformation and microstructure evolution behaviour of the powder compact during ECAP.

Finite element simulation of deformation behavior of pure aluminum during equal channel angular pressing

In this paper, the shear plastic deformation behavior of pure aluminum during a multiple-pass equal channel angular pressing (ECAP) process in Route C with the die angle Φ = 90° was investigated and analyzed, and the effect of friction on the deformation behavior was also studied, using the commercial finite element software MSC.SuperForm. It is concluded that there is a uniform region of maximum equivalent strain existing and remaining in a multiple-pass process, although the deformation is inhomogeneous in the whole workpiece. The shear direction in Y plane has an approximate obliquity of 45° relative to the longitudinal axis of the workpiece, and that the associated deformation restores the equiaxed structure in this plane after only every other pass during ECAP process in Route C. The extent of inhomogeneous deformation in the workpiece increases in the case of friction and a sharp outside corner die.

Finite element analysis of equal channel angular pressing of strain rate sensitive metals

In recent years, equal channel angular pressing (ECAP) has been the subject of intensive study in recent years due to its capability of producing fully dense samples having a ultrafine grain size. In this process, knowledge of the internal stress, strain and strain rate distribution is fundamental to the determination of the optimum process conditions for a given material. The properties of the ECAPed materials are strongly dependent on the shear plastic deformation behavior during ECAP, which is controlled mainly by die geometry, material properties, and process conditions. In this study, we applied the finite element method to obtain a better understanding the plastic deformation behavior of the workpiece during ECAP in terms of material flow properties and die geometries. The material flow stress, i.e. hardening behavior, was considered to be both strain rate dependent and strain dependent. The deformation within the workpiece is inhomogeneous unlike the ideal pure shear deformation. The mesh size dependence on the local deformation behavior in the deforming zone was addressed. The corner gap formation between the die and workpiece during the plane strain ECAP process was investigated. The mechanism of the corner gap formation is described in conjunction with the hardening behavior and local flow velocity of the workpiece in the deforming zone.

Finite element analysis of equal channel angular pressing using a round corner die

The properties of the materials are strongly dependent on the shear plastic deformation behavior during equal channel angular pressing (ECAP), which is controlled mainly by die geometry, material properties, and process conditions. In this study, the plastic deformation behaviour of the materials during the ECAP process with a round die corner angle (90°) and a frictionless condition was investigated using the commercial two-dimensional rigid-plastic finite element code (DEFORM2D). The ECAP process for these conditions was explained using the five steps based on the calculated load curve (fast increase, slow increase, fast increase, steady and finally decreasing stages). The inhomogeneous strain distribution within the workpiece was analyzed by subdividing the workpiece into a front transient zone, an end transient zone, an outer less sheared zone, and the remaining shear deforming zone. Due to the faster flow of the outer part compared with the inner part within the main deforming zone, the lesser shear zone in the outer part of the workpiece occurs. If the lesser deformation zone is ignored, the effective strain by the theoretical equation is in good agreement with the FEM results.

Simple shear plastic deformation behavior of polycarbonate plate II. Mechanical property characterization

It has been demonstrated in Part I of this research that the high degree of plastic deformation caused by the equal channel angular extrusion (ECAE) process leads to a nearly uniform molecular orientation across the extruded polycarbonate (PC) plate. In this paper, the effectiveness of the ECAE process in altering the mechanical property of PC is investigated. Significant improvements in flexural modulus and fracture toughness are observed, and are found to be closely related to the ECAE-induced molecular orientation. Microscopy observations of the fracture process show that the crack propagation direction is controlled both by the ECAE-induced molecular orientation direction and by the maximum principal stress direction, which results in the formation of hackles. Potential advantages of ECAE for fabricating polymer parts are addressed.

Simple shear plastic deformation behavior of polycarbonate plate due to the equal channel angular extrusion process. I: Finite element methods modeling

AbstractSimple shear plastic deformation behavior of polycarbonate (PC) plates due to the novel equal channel angular extrusion (ECAE) process is modeled using a commercial finite element methods (FEM) package. The true stress and true strain contour plots as well as the strain rate variation across the PC plate during the ECAE process are analyzed. The FEM results correlate well with the experimental findings. The present study indicates that the novel ECAE process is effective in producing a high degree of simple shear plastic deformation across the extruded polycarbonate plate. The high degree of plastic deformation due to ECAE induces a high level of nearly uniform molecular orientation across the extruded PC plate. As a result, significantly improved physical and mechanical properties in PC are expected. The simple shear plastic deformation behavior of PC plate, as a function of extrusion rate and temperature, is investigated. The significance of the ECAE process for fabricating polymer parts is also discussed.