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| J. Bidulská, R. Kočiško, R. Bidulský, M. Actis Grande, T. Donič, M. Martikán |
| EFFECT OF SEVERE PLASTIC DEFORMATION ON THE POROSITY CHARACTERISTICS OF Al-Zn-Mg-Cu PM ALLOY |
Abstract
The aim of this work was to perform an analysis of severe plastic deformation on the porosity characteristics of aluminium PM alloy. The studied Al-Zn-Mg-Cu aluminium alloy was pressed in two different pressures 400 and 600 MPa; than three different processing conditions (debinding at 400 °C for 60 min, sintering in a vacuum furnace at 610 °C for 30 min and Equal Channel Angular Pressing - Back Pressure) were carried out. Densification behaviour of powder particles in the studied Al-Zn-Mg-Cu aluminium alloy is complicated due to the large surface area and associated oxide layers. Therefore, the first pass of Equal Channel Angular Pressing - Back Pressure only caused powder particles to slide against each other with little appreciable deformation of them. The morphology (mainly represented by fshape and fcircle), distribution and dimension (mainly represented by Dcircle) of pores have a significant effect on the mechanical behaviour of powder metallurgy materials. Pore diameters for all processes materials are in the range of 1 to 45 ?m, however most of the pores diameter values Dcircle are in the range of 2 to 10 ?m. It could be expected that this large amount of small pores influences strongly both fshape and fcircle. Pore profile irregularity, represented by morphological parameter fcircle, is in the range of 0.23 to 0.25 and depicts evolution of pores to a smooth contour that is more effective than to a circular form during sintering, so the highest value of fshape (as a pore elongation is in the range of 0.5 to 0.6) was registered for sintered and Equal Channel Angular Pressed - Back Pressure specimen as well.
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| Keywords: aluminium alloy|SPD|ECAP-BP|FEM|porosity| |
| No 1 (2010), p. 4-11 |
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