An Assessment of the Grain Structure Evolution during Hot Forward Extrusion of Aluminum Alloy 7020

The current investigation is concerned with the grain structure evolution in an Al-Zn alloy (EN AW-7020) during the hot forward extrusion process. In order to analyze that, a miniature hot forward extrusion setup was designed which allows the quenching of the extrusion butt immediately after extrusion. In order to gain a better understanding of the process, the shape of the deformed grains was analyzed and the process was simulated. The shape of these grains was indentified in two directions in the different grain zones, e.g. dead metal zone and shear zone. The FE simulations showing the different grain zones were also illustrated. Simulation results and the micrographs were quite promising to find parameters for simulation models in order to predict grain sizes with the method presented in the current research work.</jats:p

Grain Shape Evolution and Prediction for AA6082

The microstructure of aluminum is of high importance for the mechanical properties of the product. During extrusion the material undergoes a wide range of different strain, strain rates and temperature gradients, as described in many research works [1-4]. The final microstructure and texture is the result of the effects of multiple mechanisms as grain shape change, recrystallization, recovery, and grain growth. To get optimized profiles, a well-directed adjustment of the microstructure through process parameter is a typical and critical aim. Therefore, the correlation between extrusion process parameters and the change of texture and grain size needs to be investigated [5]. The present paper describes a study on grain evolution during the first stages of material response to deformation in direct extrusion. The investigation was carried out by means of circular profile extrusion of AA6082 alloy with the aim of evaluating the dependency of texture change on process parameters such as temperature, velocity and extrusion ratio. Sequential experimental measurements on grain size were coupled with strain evaluations of a finite element model in order to define an evolution model, always taking into account existing evolution theories and laws

INVESTIGATION OF AA6082 GRAIN TEXTURE EVOLUTION AND PREDICTION

Microstructure of aluminum is of high importance for product mechanical properties. During extrusion the material undergoes a wide range of different strain, strain rates and temperature gradients, how many works reported (1). Final microstructure and texture is the result of the effects of multiple mechanisms as grain shape change, recrystallization, recovery, and grain growth. To get optimized profiles a well-direct adjustment of the microstructure through process parameter is a typical and critical aim. Therefore the correlation between extrusion process parameters and the change of texture and grain size needs to be investigated (2). The present paper reports a study on grain evolution during the first stages of material response to deformation in direct extrusion process. The investigation was carried out by means of a circular profile extrusion of AA6082 alloy with the aim of evaluate dependency of texture change over process parameters such as temperatures, velocity and extrusion ratio. Sequentially experimental measurements on grain size have been coupled with strain evaluation of finite element model in order to define an evolution model, always taking into account existing evolution theories and laws

Manufacturing of Steel-Reinforced Aluminum Parts by Co-Extrusion and Subsequent Forging

The processes of manufacturing continuously and discontinuously steel-reinforced aluminum profiles by means of co-extrusion and subsequent forging were examined. In the co-extrusion and subsequent forging of discontinuously reinforced parts, influences of the reinforcing elements on forming behavior and material bonding for both processes were investigated. It was shown that forming temperature as well as ram speed have no influence on joining quality and forming behavior of the reinforcing elements in the co-extrusion of continuously reinforced profiles. The analyses of the joining zone between the composite partners revealed that a good connection of the two materials could be achieved.</jats:p

Investigation And Prediction of Grain Texture Evolution in AA6082

Extrusion applications require a strict control of the mechanical proprieties of the extrudates, in particular when undergoing severe loading conditions like in the transportation sector. Profile mechanical properties directly depend on its microstructure and texture, which are the result of multiple mechanisms based on precipitation mechanism or on grain shape evolution (grain refinement, recrystallizations, recovery and grain growth). In this direction, predicting the final profile microstructure under specific process parameters in the die design stage is of great relevance. The present study involved experimental activity on grain size measurements of profile and butt during interrupted direct extrusion of an AA6082 round profile. The grain size measurements were coupled with simulation results in order to regress analytical models based on effective strain, strain rate and temperature. Finally, the developed model was implemented in the numerical code by means of a subroutine that can be used as microstructure prediction tool