About recrystallization of aluminum in the radial extrusion

Dombrovskiy Evgeniy
Donetsk National Technical University

The supervisor of studies: Yan Beygelzimer

A promising method for axisymmetric parts with flanges and thickening is the radial squeezing. It is over the metal in the radial direction. The presence of high degrees of deformation makes it possible to obtain accurate and quality filling in the form of finished product. The economic effect is achieved by reducing the flow metal, which is an important factor in the manufacture of parts from non-ferrous metals .For research process radial extrusion, and conduct pilot reserch in DonFTI has developed a new scheme of radial extrusion, which is the presence of punch. This design feature allows you to solve two problems: First, it provides a uniform radius of the metal during the second - creates a more complex configuration workpiece, the most close to the ultimate form of izdeliya.For research were used cylindrical samples of technically pure aluminum AD1. Samples were made by turning of the rods, followed by annealing. As a lubricating material using a mixture of wax, castor oil, and rosin. Extrusion occurred at room temperature, ie sample previously heated. Recording of the working sensors was carried out using the kit tensometric equipment.

Figure 1 - Schedule of distribution of hardness along the length of the specimen from the center

Derived from the installation of products were cut samples, followed by buffing them, revealing the structure were conducted measurements of firmness. The paper provides a schedule of distribution of hardness along the length of the sample from left to right (Figure 1), Microstructure source (Figure 2) and the deformed aluminum (Figure 3).

Figure 2 - Microstructure initial sample

Figure 3 - Microstructure of the specimen deformed

From the graph (Figure 1) we can see that the hardness of the length of the sample is different and is distributed as follows: near the center of the low, then as far as the removal of the center is growing, and moving towards the periphery becomes lower. As a result, the processing of the data put forward by several assumptions supporting the distribution of hardness along the length of the specimen. The first assumption is the loosening of material due to the specificity of the flow in the radial extrusion. Ie there are considerable tensile stresses in the radial direction, which may lead to the formation of cracks and other defects. Second - the dynamic recrystallization of aluminum in the process of deformation, which is due to intense plastic deformation, directed to the periphery. As well as the possibility of combining the first two hypotheses.