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Open access

J. Senderski, M. Lech-Grega and B. Płonka

Studies of Advanced Technologies Used in the Manufacture of Products from Aluminium Alloys

The test stands already put in operation and still under development, installed in the Light Metals Division Skawina of the Institute of Non-Ferrous Metals in Gliwice are described. The presentation includes 5MN horizontal direct-indirect extrusion press, 2,5MN vertical forging press, "MeltechConfex MC-260" device for continuous rotary extrusion process, "Melt-Spinning" plant for casting of thin strips, melting-casting plant for Mg alloy billets, heat treatment line, and new testing equipment, including Instron 5582 100 kN and Instron 600DX 600 kN testing machines with attachments for tests carried out at low and high temperatures, automatic hardness tester for HB, HV and HRC hardness measurements, portable X-ray diffractometer for measurement of internal stresses, optical emission spectrometer with channels for the analysis of aluminium and magnesium alloys, STEM 200kV transmission electron microscope, and apparatus for hydrogen content measurement in the solid state. Based on the experimental potential and apparatus available, present research opportunities were discussed and modern trends in the advanced technology of Al and Mg alloys fabrication were outlined.

Open access

S. Boczkal, M. Lech-Grega and B. Płonka

Abstract

The structure and properties of AZ61 alloy after deformation by ECAE were characterised. Alloy structure was examined after the successive passes of ECAE process, to study the effect of deformation on the morphology of γ phase precipitates and the size and shape of grains. Based on EBSD analysis, the occurrence of high angle boundaries was stated. An attempt was made to describe the mechanisms that are operating when the deformation route is changed at 300°C in the AZ61 alloy processed by ECAE method. Alloy hardness after the first cycle of deformation was stabilised at the level of 80-90 HB. Based on the hardening curve and the occurrence of high angle grain boundaries (>15°), the possibility of further deformation of the AZ61 alloy was confirmed.

Open access

B. Płonka, P. Korczak, K. Remsak and M. Lech-Grega

Abstract

The paper presents the results of the die forging tests of a modified EN AW-6101 alloy with the addition of Zr, using two types of the feedstock materials. The first feedstock materials were ingots cast in a vertical semi-continuous process, the second feedstock materials were extruded rods. The die forging process was carried with parameters enabling “on line” heat treatment (T5 temper). For comparison, forgings were also heat treated to the T6 temper and to thermo-mechanical treated to the T8 and T9 temper. Then forgings made from both feedstock materials were characterised in terms of structure, mechanical properties and electrical conductivity.

Open access

A. Milenin, M. Gzyl, T. Rec and B. Plonka

Abstract

Mathematical model of small-diameter wires extrusion from biocompatible MgCa08 (Mg - 0.8% Ca) magnesium alloy was developed in the current paper in order to determine window of allowable technological parameters. Compression and tensile tests were carried out within temperature range 250-400°C and with different strain rates to determine the fracture conditions for the studied alloy. Finite element (FE) analysis was used to predict the billet temperature evolution and material damage during processing. The extrusion model takes into account two independent fracture mechanisms: a) surface cracking due to exceeding of the incipient melting temperature and b) utilization of material formability. FE simulations with different initial billet temperatures and pressing speeds were performed in order to determine the extrusion limit diagram (ELD) for MgCa08 magnesium alloy. The developed ELD was used to select the parameters for the direct extrusion of wires with diameter of 1 mm. Then, the extrusion of twelve wires was conducted at 400°C with pressing speed 0.25 mm/s. It was reported that the obtained wires were free from defects, which confirmed the good agreement between numerical and experimental results.

Open access

B. Płonka, K. Remsak, P. Korczak, M. Lech-Grega and M. Rajda

The aim of the study was to test and assess products extruded from the magnesium alloys type MgAlZn: AZ31, AZ61 and AZ80A alloys in the form of Ø35mm round bars and 80x15mm flat bars. The test material was extruded in a direct system with the ram feed speed of 1 mm/s and the extrusion ratio λ = 7 ÷ 9. The extruded bars were examined in as-extruded state and after heat treatment to the T5 temper and T6 temper. The strength properties were tested and microstructure was examined with calculation of the average grain size.

Open access

B. Płonka, J. Kut, P. Korczak, M. Lech-Grega and M. Rajda

The Influence of Extrusion Process Parameters and Heat Treatment on the Mechanical Properties of High-Strenght Magnesium Alloy

The article consists test results of direct extrusion AZ80A & ZK60A magnesium alloys. Extrusion process was conducted in the temperature range 350°C-450°C at different extrusion speeds (ram speed 0.8 mm/s and 2.8 mm/s). In order to find optimum precipitation strengthening parameters the aging curves have been made. Extruded rods were characterized by mechanical properties in different tempers. Basic structure researches of magnesium alloys have been made.

Open access

B. Plonka, K. Remsak, M. Nowak, M. Lech-Grega, P. Korczak and A. Najder

Abstract

The object of this study was to develop parameters of plastic deformation process of magnesium alloy - ZK60A. The tests have showed that for this alloy it is possible to use the temperature of the plastic deformation process ranging from 350°C to 450°C. Samples were characterized by mechanical properties and structure in different heat treatment tempers. This magnesium alloy obtained in the T5 temper higher mechanical properties then T6 temper. The paper also presents research results of investigation of conversion coating on ZK60A magnesium alloy by anodic oxidation method in non-chromium solutions. It was found that the coating produced in non-chromium solutions show considerable increase of corrosion resistance of tested alloy.

Open access

B. Płonka, M. Lech-Grega, K. Remsak, P. Korczak and A. Kłyszewski

The object of this study was to develop parameter of the die forging process, such as feedstock temperature and to investigate her impact on the structure and mechanical properties of magnesium alloys in different heat treatment conditions. Tests were carried out on a 2,5MN maximum capacity vertical hydraulic press using forgings of sample (model) shapes. Then, based on the results obtained in previous work, research was carried out to develop for items forged from magnesium alloys the parameters of heat treatment to the T5 and T6 condition in the context of achieving possibly homogeneous and fine-grained structure and, consequently, high mechanical properties.

Open access

M. Nowak, B. Płonka, A. Kozik, M. Karaś, M. Mitka and M. Gawlik

The resultes of anodic oxide conversion coatings on wrought AZ61 magnesium alloy production are describe. The studies were conducted in a solution containing: KOH (80 g/l) and KF (300 g/l) using anodic current densities of 3, 5 and 10 A/dm2 and different process durations. The obtained coatings were examined under a microscope and corrosion tests were performed by electrochemical method. Based on these results, it was found that the low-voltage process produces coatings conferring improved corrosion resistance to the tested magnesium alloy.

Open access

B. Płonka, M. Rajda, Z. Zamkotowicz, J. Żelechowski, K. Remsak, P. Korczak, W. Szymański and L. Snieżek

The objective of the study was to determine the feasibility of plastic forming by hot rolling of the AA2519 aluminium alloy sheets and cladding these sheets with a layer of the EN AW-1050A alloy. Numerous hot-rolling tests were carried out on the slab ingots to define the parameters of the AA2519 alloy rolling process. It has been established that rolling of the AA2519 alloy should be carried out in the temperature range of 400-440°C. Depending on the required final thickness of the sheet metal, appropriate thickness of the EN AW-1050A alloy sheet, used as a cladding layer, was selected. As a next step, structure and mechanical properties of the resulting AA2519 alloy sheets clad with EN AW-1050A alloy was examined. The thickness of the coating layer was established at 0,3÷0,5mm. Studies covered alloy grain size and the core alloy-cladding material bond strength.