Die Channel Angle Research Articles

Investigation of Severe Plastic Deformation Effects on Magnesium RZ5 Alloy Sheets Using a Modified Multi-Pass Equal Channel Angular Pressing (ECAP) Technique.

The present study investigates the effects of multiple passes of equal channel angular pressing (ECAP) on magnesium alloy sheets with the assistance of an Inconel plunger along with a die setup having a channel angle of 120° and corner angle of 10° operating at a temperature of 200 °C followed by the required heat treatment processes. The microstructural analysis of the sheet samples at various stages of the multi-pass hot ECAP has shown evidence of ultrafine grain refinement (UFG) due to the occurrence of severe plastic deformation. X-ray diffraction analysis has also exhibited the presence of phases like MgZn and CeZn3 which is supposedly responsible for the enhancement of the mechanical properties. As a result, the room temperature tensile and compressive strengths have improved by 6.12% and 6.63%, respectively, after the second pass, and 11.56% and 15.64%, respectively, after the fourth pass of ECAP. Additionally, the hardness of the sheets has increased by 6.49% and 16.64% after the second and fourth pass of hot ECAP, respectively, mainly attributed to the drastic decrease in grain size from 164 μm to 12 μm within four ECAP passes, all these with a negligible change in ductility. This success in the thermomechanical processing of Mg-RZ5 alloy sheets using a die channel angle of 120° with a minimal number of passes of hot ECAP under a controlled equivalent strain, further opens doors for incorporating optimizations and/or additional aspects so as to achieve even better grain refinements, and consequently, mechanical strength improvements thereby catering to the industrial needs of aerospace and construction areas.

Correction: Influences of die channel angles on microstructures and wear behaviors of AZ61 wrought magnesium alloy fabricated by extrusion-shear process

Correction: Influences of die channel angles on microstructures and wear behaviors of AZ61 wrought magnesium alloy fabricated by extrusion-shear process

The Effect of ECAP Processing Conditions on Microstructural Evolution and Mechanical Properties of Pure Magnesium-Experimental, Mathematical Empirical and Response Surface Approach.

In this study, a quantitative evaluation approach was used to investigate how certain ECAP processing parameters affect the microstructural evolution, Vicker’s microhardness values and tensile properties of pure Mg. The ECAP processing parameters were number of passes, ECAP die channel angle and processing route type. The response surface methodology (RSM) technique was used to design 16 runs of the experiment using Stat-Ease design expert software. Billets of pure Mg were processed up to four passes of routes Bc, A and C at 225 °C. Two ECAP dies were used with internal channel angles of 90° and 120°. Experimental findings were used to establish empirical models to assess the influence of the ECAP processing parameters on grain size and mechanical properties of ECAPed billets. The established relationships were examined and validated for their adequacy and significance using ANOVA as well as several statistical criteria. Response surface plots and contour graphs were established to offer better understanding of the intended relationships. In addition, the optimum processing parameters for grain size, hardness values and tensile properties were defined. Both experimental results and the theoretical model revealed that route Bc is the most effective route in grain refining. The experimental findings showed that four passes of route Bc through the die channel angle 90° revealed a significant reduction in the grain size by 86% compared to the as-annealed counterparts. Similar to the grain size refining, four-passes processing through the ECAP die with an internal channel angle of 90° leads to improved Vicker’s microhardness values. Additionally, four passes of route Bc using the 90° die angle recorded a significant HV increase at the edge and central areas by 112% and 78%, respectively, compared to the as-annealed counterpart. On the other hand, according to the optimization findings, two passes of route Bc using a die angle of 120° resulted in the best ultimate tensile strength for pure Mg, whereas four passes of route Bc revealed the optimum ductility at fracture.

Microstructures and Corrosion Behavior of AZ61 Magnesium Alloy Prepared by Extrusion–Shear with Different Die Channel Angles

Microstructures and Corrosion Behavior of AZ61 Magnesium Alloy Prepared by Extrusion–Shear with Different Die Channel Angles

A Review on Effect of Stress and Strain Distribution on the AA5083 With Respect to Different Channel Angle of ECAP

The focus of this study was on the effect of channel angle on stress distribution in the material aluminum alloy 5083. The mechanical properties of a mate- rial are related to the grain size. Equal channel angular pressing (ECAP) is a method for deforming materials in such a way that a strong mechanical prop- erties material is formed while the dimensions of the work piece stay fixed in order to make ultra-fine-grained materials. One of the parameters of ECAP is the channel angle. It’s crucial to understand the impact of a die channel angle on material stress distribution before designing one. When the work piece passes through the channel angle, the die channel angle is built differently to see the effect of stress distribution. At the place where the die’s channels angle intersected, the grain structure was evaluated. The result of the influence of die channel angle on stress distribution is shown in this study’s analysis. It is well established that the channel angle has an impact on mechanical behaviour. The inhomogeneity index (Ci)and standard deviation (S.D.) are two approaches for assessing strain homogeneity. Ciis demonstrated to be an ineffective tool for analysing strain distribution homogeneity. Furthermore, it is advised that constructing Equal Channel Angular Pressing die geometry to obtain the best strain circulation homogeneity rather also the best efficient strain consequence is preferable.

Equal channel angular pressing die design through finite element analysis method for non-strain hardening material

ABSTRACT The present research aimed to optimise process parameters such as outer corner angle (ψ = 0°–36°), frictional coefficient (μ = 0–0.05), inner corner angle (ω = 0°–8°) and die channel angle (φ = 90°–120°) for the equal channel angular pressing (ECAP) die design considering a non-strain hardening material Al6061-T6 alloy using ABAQUS finite element analysis software in terms material flowability, corner gap formation, surface gap formation, induced strain intensity and strain distribution. The ECAP die having 100° φ, 24° ψ, 0.02 μ and 8° ω provide better material flowability, (no corner gap formation and surface gap formation), moderate induced strain intensity and homogeneous distribution. The ECAP processing on the designed die effectively modifies the microstructure morphology of as-cast Al6061 alloy. The α-Al grain size decreases and roundness increases and the thicker grain boundary is altered into the thinner boundary, as an effect of this, hardness and tensile strength improved by 28.3% and 32.7%, respectively.

Effect of processing parameters on equal-channel angular pressing of aluminum alloys: An overview

Equal-channel angular pressing (ECAP) is one of the emerging Severe plastic deformation (SDP) technique that makes ultra-fine grains (UFG) microstructure to improve the properties of different materials and composites. The uniqueness of the ECAP technique is that it can refine the grain size without changing the cross-section. Many factors like processing temperature, number of ECAP passes, die channel angle and processing route affects the results obtained from ECAP technique. This review is mainly focused on the mechanical and microstructural properties of aluminium alloys generated after ECAP Process along with number of passes. It is observed as the number of passes increased the hardness and tensile strength of the alloy increase and ductility of the material is reduced. The maximum percentage of grain refining is obtained in the first two or three passes after that no significant changes were observed because the effect of temperature is more than the effect number of passes on the grain size.

A Statistical Method to Predict the Hardness and Grain Size After Equal Channel Angular Pressing of AA-6063 with Intermediate Annealing

Fine-grained metals and alloys with a homogeneous microstructure can be produced in bulk quantities using the equal channel angular pressing (ECAP) technique. In the ECAP process, improvements in desired properties and grain refinement depend on die geometry, number of passes, strain per pass, plunger speed, friction conditions, processing temperature, etc. In the present study, Al-6063 alloy cylindrical samples are processed by ECAP varying three critical parameters: die channel angle, number of passes, and intermediate processing temperature. Optical microscopy, electron back scattered diffraction, scanning electron microscopy, and transmission electron microscopy techniques are used for observing grain size and refinement, deformation patterns, the formation of precipitates etc. The main consequence of the thermomechanical effect is a reduction in grain size from micro to nano is observed. This transformation makes the material better, which shows outstanding promises on ECAP results. The developed material can be highly applicable in research as well as in the automotive industry.

Theoretical and Numerical Investigation of Required Torque in ECAP-Conform Process

In recent years, special attention has been paid to continuous methods of severe plastic deformation, such as the ECAP-Conform process. In this research, a new analytical method has been presented to calculate the required torque in ECAP-Conform of grade 2 commercially pure titanium (CP-Ti Gr. 2). In this regard, the process was divided into two regions, mainly the primary roll bending and the secondary ECAP zones. The energy balance method, as well as the upper-bound analysis, was used to calculate the required force and torque in the first and the second regions, respectively. Also, the ABAQUS/Explicit solver was utilized to simulate the ECAP-Conform process, as well as the numerical results, were compared with the theoretical outcomes. The shear friction factor between the die and the CP-Ti rod was estimated by the ring compression test for different lubricating conditions. It was found that whereas the friction factor plays an essential role in the implementation of the process, the hardening exponent of the raw material has a negligible effect on the required torque. Furthermore, in ECAP-Conform of AA6061 rod, the required torque for different die channel angles was calculated and compared with other researches. It was found that the results of the proposed theory had acceptable compliance with the numerical simulation.

Equal channel angular pressing of the aluminium alloy: A numerical investigation

Equal channel angular pressing (ECAP) is adopted as the most popular bulk severe plastic deformation (SPD) processing technique and has been utilised for the grain refinement in several metals and alloys. The aforesaid technique, in which the metallic billet processes through a simple shear was investigated by finite element analysis in this work. The die channel angle for the investigation was selected by considering the minimum energy consumption for the induction of maximum uniform strain. Out of preferred channels, 110° was found suitable. Al-6063 was considered as work material. Maximum load requirement for accomplishing the operation, effective stress and strain distribution were also inquired. The mathematically calculated equivalent plastic strain value found in close proximity to the value obtained from the FEA. In the process die channel angle and friction conditions are primarily responsible for maximum strain induction in the work material, which was affirmed here by the numerical analysis. In addition to it these two parameters influence the maximum load requirement for accomplishing the operation whereas, ram rate within the investigated range has the negligible impact.

Microstructure Evolution of AA1070 Aluminum Alloy Processed by Micro/Meso-Scale Equal Channel Angular Pressing

The Micro/meso-forming of commercially pure aluminum, AA1070, processed at room temperature by equal channel angular pressing (ECAP) with a die channel angle of 90° through 4 deformation passes has been conducted. Microstructure features, such as grain size, misorientation angle distributions and the developed texture during the four deformation passes of micro/meso-ECAP have been investigated by Electron backscattering diffraction (EBSD) technique. Then, hardness measurements over the cross-section of the processed samples were correlated with the EBSD analysis. EBSD scans revealed that extended shear bands are formed and represent the microstructural feature induced during micro/meso-forming. Whereas, a non-uniform grain structure consisting of intensive low-angle grain boundaries was obtained in the first pass, a uniform ultrafine-grained structure of high-angle grain boundaries (in the range of 1–2 μm) was achieved at the fourth pass. Consequently, a significant improvement in the hardness value to 65.3%, with respect to the starting material, was achieved due to the enhancement of the fine grain structure. The texture analysis exhibited that the high plastic shear strain associated with micro/meso-scale ECAP was capable to develop a weak texture in the flow plane compared to the starting texture.

Effects of severe plastic deformation by ECAP on the microstructure and mechanical properties of a commercial copper alloy

This work is concerned with the comparison of the microstructural and mechanical properties changes in a low alloy copper by Equal channel angular pressing and intermediate annealing at different temperatures (room temperature, at 250 °C and 450 °C after every pass). The die channel angle used was 100°, and the back angle was 10°. We have investigated the mechanical properties of Vicker’s hardness, ultimate tensile strength (UTS), offset yielding strength (YS), percentage elongation (ef), along with the microstructural changes that produce changes in texture and resultant small sizes of grains. The processing combination of annealing at 250 °C and Route-C ECAP die extrusion results in far superior mechanical properties as compared to other treatments while generating uniformity in the microstructure. This work includes the microstructural analysis using optical microscopy, fractography images (SEM), tensile strength, and EBSD (Electron Back-scattered Diffraction) and x-ray powder diffraction. The processing combination shows outstanding promise and the annealing effects on ECAP results can be highly useful for industrial and research applications.

Effect of Milling Time on Consolidation of Al5083 Nanocomposite by Equal Channel Angular Pressing

The effect of milling time on consolidation of Al5083-5wt. % nanoyttrium oxide powders which are milled from 0-35 hours using planetary ball mill. nanocrystalline structure was observed after 10hours of milling. X-ray diffraction results reveals the formation of 57nm and 31nm for 20hr and 35hr of milling with increase in lattice strain. Circular and Elliptical morphology of milled powders were confirmed through SEM with decrease in particle size. The 90o die channel angle ECAP die was used to consolidate 20hr and 35hr milled powder aided with and without back pressure. The optical micrographs reveal the formation of fine grains. The35hr milled powder shows the maximum densification of 96% and 20hr milled powder shows maximum hardness of 82HRB was observed in 20hr milled powder. Both are consolidated for two passes in route-A and sintered at 430°C for one hour.

Synthesis of Al5083 Alloy by High Energy Ball Mill and Densification through Equal Channel Angular Pressing (ECAP)

An attempt was made to synthesis Al-5083alloy through high energy ball milling and densification through ECAP. The elemental powders consisting of Al5083 was milled for 5, 10 and 15 hrs using Retsch high energy ball mill (PM400). The physical and structural properties of mechanically alloyed particulates were characterised by diffraction methods and electron microscopy. The 15hrs nanocrystalline structured particulates of Al5083 alloy shows crystallite size of 15nm. Scanning Electron Microscope (SEM) reveals the morphology of alloy which is irregular shaped. The size of alloyed particulates also measured using SEM and found to be 7μm for 15hrs of milling. The 15hr milled alloy particulates were densified by ECAP through 90o die channel angle. Maximum densification of 92% and highest hardness of 63HRB was achieved for sample consolidated with route-A for two passes along with sintering.

Finite Element Analysis of Aluminum Alloy at Many Die Channel Angles using DEFORM-3D

Equal channel angular pressing (ECAP) is a technique used to impose strain in material which helps to increase the mechanical properties of a material. It is generally used to refine grain size of the material by passing sample through equal channel. In this study, analysis on frictional effect in equal channel angular pressing using aluminum 1100 has been done by using FEM software DEFORM-3D version 10.1. Dies with different channel angle were designed with the help CATIA. This study shows the effect of friction with different die channel angle. It has been found that with the increase in friction, reduction in corner gap is found (dead zone), which may cause material damage and improve strain distribution homogeneity. The result obtained with FEM simulation are compared to those obtained theoretically, thus it is found that the current study is in good agreement to the theoretically result.

The Effect of Die Channel Angles and their Combination on Plastic Deformation of Pure Copper during Equal Channel Angular Pressing Using Finite Element Modelling

It was investigated the effect of die channel angles and their combination on plastic deformation of pure copper during ECAP under friction and frictionless conditions using 2-D elastic-plastic finite element modelling. A sound knowledge obtained for the plastic deformation (material flow) and understood the relationships between plastic deformations. The modelling results suggested that strain inhomogeneity was lesser in channel angle 120o than channel angle 90o and pressing load as well as strain decrease with increasing die channel angle. The friction influence in case of combination of channel angles was negligible as compare to individual channel angles. The strain generation and distribution was more uniform in case of combination of channel angles as compare to individual channel angles.

Evaluating influence degree of equal-channel angular pressing parameters based on finite element analysis and response surface methodology

The current paper presents a collection of numerical, mathematical, and statistical techniques to predict strain behavior and required pressing force of 7075 aluminum alloy within the different parameters of equal-channel angular pressing (ECAP). Accordingly, response surface methodology was utilized to estimate the contribution percentage of the processing parameters (i.e., die channel angle, outer corner angle, coefficient of friction, and punch rate) on effective plastic strain, standard deviation of effective strain, and required pressing force of the deformed sample; then, regression modeling relationships were presented for each of the three outputs. Also, a suitable coincidence was found between the predicted regression model, numerical approach, theoretical technique, and experimental work. It is found that the achieved results could be used as a successful guideline for evaluation of the ECAP process.

Microhardness evolution of pure titanium deformed by equal channel angular extrusion

Microhardness homogeneity was assessed on commercial pure titanium processed by equal channel angular extrusion (ECAE). The operation was performed with die channel angle of 90° and processing temperature of 450 °C by route BC up to six passes. The Vickers microhardness measurements were investigated on both cross-sectional and longitudinal planes of the annealed, one-, two-, four-, and six-pass ECAEed titanium. It was found that the application of the process and the addition of pass numbers lead to the improvement of hardness magnitude. It was shown that there are some areas of microhardness heterogeneity in surrounding and bottom regions of the one-pass and two-pass specimens at the cross-sectional plane which is slightly disappeared by adding the pass numbers. Furthermore, there is a suitable amount of hardness homogeneity in the longitudinal plane, irrespective of the specimen condition. It can be concluded that a desirable homogeneity of hardness can be attained after imposing six passes of ECAE process on both cross-sectional and longitudinal planes of titanium.

Effective Damage Indicator for Aluminum Alloy (AA6082Zr) Processed by ECAE

The present research aims to study the influence of equal channel angular extrusion (ECAE) parameters (die channel angle, die corner angle, and friction coefficient) on cracking and fracture tendency. For this type of analysis, a MATLAB code integrated with finite element Abaqus/Explicit model was developed and used. A parametric study is done to investigate how the damage tendency varies with changes of ECAE parameters. The distribution of the damage factor based on Cockcroft–Latham equation for different channel angles, corner angles, and friction coefficients is depicted. It is observed that the appearance of cracks on the upper surface is more likely to occur than on the lower surface. The reduction in friction coefficient does not guarantee minimum damage tendency. Finally, the optimum parameters for reducing the fracture tendency in ECAE are presented.

Microstructural and Hardness evolution of AZ80 alloy after ECAP and post-ECAP processes

This research paper investigates the microstructure evolution and hardness variation of wrought AZ80 magnesium alloy after each ECAP passes. The strengthening effect of AZ80 alloy was examined after post-ECAP aging treatment. Alloys were severely deformed through equal channel angular press at 533K using route Bc with a die channel angle (ϕ) 1100 and corner angle (ψ) 300. Subsequently, the microstructural characterization was studied using optical microscope (OM) and scanning electron microscope (SEM). Further, post-ECAP aging treatment at 523K for 6h and 12h was performed and microhardness of the specimens was measured. It was found that the grain refinement through thermo-mechanical processing of ECAP and Post-ECAP treatment significantly improves the microhardness of the Mg alloy, which directly influences the properties of wrought AZ80 magnesium alloy