D. Salcedo

Development of Nanostructured Armco-Fe by Equal Channel Angular Extrusion (ECAE)

The Equal Channel Angular Extrusion or Pressing (ECAE/ECAP) process has been developed over these last years in order to obtain nanostructured materials by means of severe plastic deformation. These applications have been mainly focused on light alloys while its application to iron and steel has not been so common. This is due to the difficulties that their ECAE processing implies, as much higher values for the processing force are required. In this present study, the results achieved when Armco-Fe is processed by ECAE at room temperature are shown. In addition, a comparative study on the variation in the mechanical properties (yield stress, ultimate tensile strength, and elongation at break) is shown when different thermal treatments are employed. Specific combinations are also shown of the thermal treatments which lead to a higher value of elongation and mechanical strength in relation to the starting material. Furthermore, an analysis of the obtained results is made by optical and scanning electron microscopy techniques.

FEM Modelling and Experimental Analysis of an AA5083 Turbine Blade from ECAP Processed Material

This present research work deals with the design by finite element method (FEM) of the dies required for the isothermal forging of a Francis turbine blade taking into account that the starting material has been previously nanostructured through severe plastic deformation by equal channel angular extrusion. This nanostructured material possesses improved mechanical properties and hardness, better forgeability, and, under specific conditions, a superplastic behavior. Once this material is obtained, its flow rule has been determined through compression tests at different temperature values along with its subsequent fitting with artificial neural networks. Later on, these rules will be employed in the FEM simulations included in this present study. Furthermore, the results of the processing of these materials are shown comparing the properties of the mechanical components after their isothermal forging at different temperature values both with predeformed and non-predeformed material. This work is at the cutting-edge of technology because there are only a few technical papers about forging applications of nanostructured material.

Comparison between FEM and Experimental Results in the Upsetting of Nano-Structured Materials

Over recent years, some severe plastic deformation processes have been developed with the aim of obtaining a material with sub-micrometric or even nanometric grain size, such as: ECAE (Equal channel angular extrusion) and HPT (High pressure torsion) among many others. The main aim of this present study is to analyse the upsetting of the 5083 Al-Mg-Mn alloy, which had been previously deformed by ECAE. Different processing temperatures will be used and the final properties of the resulting material will be determined.

Simulation and analysis of isothermal forging of AA6063 obtained from material processed by equal channel angular pressing severe plastic deformation

In this research study, a comparative examination on the mechanical properties of AA6063 has been carried out after having been processed by isothermal forging, using plane-shape dies and starting from different initial deformation states. It introduces the novelty of employing experimental data obtained from the isothermal forging so as to model the flow rules of AA6063 processed by equal channel angular pressing taking temperature into account and using artificial neural networks to this end. Subsequently, these flow rules are employed to model the behaviour of AA6063 by means of finite element simulation. Furthermore, a validation of the experimental results is made with those obtained from the simulations using the flow rules attained with the neural networks. It is shown that it is possible to achieve higher precision than with traditional fitting methods of flow rules. In addition, this study presents the novelty of carrying out a comparative study between different starting material states, prior to forging, including among these material previously processed by the severe plastic deformation process, which is referred to as equal channel angular pressing. Moreover, the experimental results obtained when processing the aluminium alloy by equal channel angular pressing are compared to those states, which correspond to the traditional way of working on aluminium alloys, which can be quenched and aged for the purpose of improving their mechanical properties.

Analysis on the Manufacturing of an AA5083 Straight Blade Previously ECAE Processed

Over these past few years, there have been a large number of technical papers published related to the problem of improving the mechanical properties of materials obtained through severe plastic deformation. Nevertheless, the number of technical papers dealing with improvement in the mechanical properties of mechanical components manufactured from submicrometric grain size material has not been so proficient. Therefore, in this present research work, a straight blade has been manufactured starting from AA-5083 previously processed by ECAE twice (N2) with route C. This material will be manipulated so as to be isothermally forged at different temperature values. This present research work shows the results that are inherent in an improvement in the mechanical properties and the microstructure achieved in the thus obtained components, compared with the starting material. In addition, the optimum forging temperature to achieve these components will be determined. As shown in this research work, it is possible to obtain submicrometric grain size mechanical components with a higher mechanical strength than those obtained in nonultrafine grained materials. The originality of this research work lies in the manufacturing of actual mechanical components from ECAE processed material and the analysis of their properties.

A Method for Obtaining Spur Gears from Nanostructured Materials

ECAE process is a novel technology which allows us to obtain materials of sub-micrometric and/or nanometric grain size as a result of accumulating very high levels of plastic deformation in the presence of high hydrostatic pressure. This avoids the material being fractured and permits very high values of plastic deformation to be obtained (ε>>1). Therefore, these nanostructured materials can be used as starting materials for other manufacturing processes such as: extrusion, rolling and forging among others; with the advantage of providing nanostructure and hence improving the mechanical properties. In this present study, forging by finite element of materials that have been previously predeformed by ECAE is analysed. MSC.MarcTM software will be employed with the aim of analysing the possibility of manufacturing mechanical components (spur gears) from materials nanostructured by ECAE.

Experimental and FEM Analysis of the AA 6082 Processed by Equal Channel Angular Extrusion

Recent studies have shown that severe plastic deformation processes (SPD) improve the mechanical properties of the processed parts. Some of the most outstanding SPD processes are as follows: High Pressure Torsion (HPT), Repetitive Corrugation and Straightening (RCS), Cyclic Extrusion Compression (CEC), Accumulative Roll Bonding (ARB), Conform and Continuous Combined Drawing and Rolling (CCDR), among others, but the most well-known is Equal Channel Angular Extrusion or Pressure (ECAE/ECAP). The aim of these processes is to introduce high values of deformation inside the parts in order to reduce the grain size and thus to improve the mechanical properties of the starting material. The study of the damage imparted to an AA-6082 alloy is made in the present work. This alloy is received as cast and it is quenched at a temperature of 530 °C during 4 hours in order to be processed by ECAE at room temperature using different geometries of the dies. The imparted damage is also studied by using FEM simulations.

Modeling of the Behavior of an Aluminum Metallic Foam by Both FEM and Experimental Results

Aluminum foams are porous metallic materials which possess an outstanding combination of physical and mechanical properties such as: a high rigidity with a very low density. In this present research work, a study on the upsetting of an aluminum foam (with a density = 0.73 g/cm3) is carried out by employing different compression velocity values. From the results obtained, it is possible to determine the material flow stress for its subsequent use in finite element simulations (FEM). Once the material flow stress has been determined, it will be employed in order to analyze the conformability of several parts by FEM.

Finite element modelling and experimental analysis of the processing conditions for obtaining straight blades by isothermal forging of a nanostructured aluminium-magnesium alloy

In this present study, both the design and the optimal manufacturing conditions for processing a straight blade by isothermal forging are shown. The starting material has been previously deformed by a severe plastic deformation (SPD) process known as equal channel angular extrusion (ECAE). As is well-known, the ECAE process is a technology which allows us to obtain materials with sub-micrometric grain size. These nanostructured materials can be employed afterwards as initial materials for other manufacturing processes. The use of these ultra fine grain sized materials (UFG) provides improved mechanical properties such as: greater hardness and mechanical strength, among others. In this present study, FEM simulations of the isothermal forging of an AA5083 previously deformed by ECAE will be carried out. The total equivalent plastic strain, the damage and the forces required to carry out the isothermal forging of this nanostructured aluminium alloy will be determined.

FEM analysis of spur gears forging from nano-structured materials

The ECAE process is a novel technology which allows us to obtain materials with sub-micrometric and/or nanometric grain size as a result of accumulating very high levels of plastic deformation in the presence of a high hydrostatic pressure. This avoids the fracture of the material and allows us to obtain very high values of plastic deformation (ϵ >>1). Therefore, these nano-structured materials can be used as starting materials for other manufacturing processes such as: extrusion, rolling and forging, among others; with the advantage of providing nanostructure and hence, improved mechanical properties. In this present work, the forging by finite element method (FEM) of materials that have been previously processed by ECAE is analyzed. MSC. MarcTM software will be employed with the aim of analyzing the possibility of manufacturing mechanical components (spur gears) from materials nano-structured by ECAE.