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Właściwości mechaniczne stopów EN AC-45000 (AlSi6Cu4) i AlSi17CuNiMg po obróbce cieplnej

Jarco A.

Inżynieria Maszyn

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2017

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R. 22, z. 1

58--64

PL

W artykule zaprezentowano wyniki badań wpływu różnych wariantów obróbki cieplnej na właściwości mechaniczne dwóch stopów: EN AC-45000 (AlSi6Cu4) i AlSi17CuNiMg, które poddano wyżarzaniu ujednorodniającemu, utwardzaniu dyspersyjnemu oraz obróbce polegającej na połączeniu tych dwóch zabiegów. Badania właściwości mechanicznych przeprowadzono na znormalizowanych próbkach odlanych w koliach. Ujednorodnianie znacząco wpłynęło na poprawę plastyczności stopu w porównaniu do stopu wyjściowego, dlatego przeprowadzono je przed utwardzaniem dyspersyjnym. Pozwoliło to na uzyskanie wzrostu wydłużenia badanych stopów przy zachowaniu bardzo dobrych właściwości wytrzymałościowych (wytrzymałości na rozciąganie Rm i twardości HB) w odniesieniu do stopu po standardowej obróbce T6 (przesycaniu i sztucznym starzeniu). Ponadto przeprowadzona obróbka cieplna wpłynęła pozytywnie na postać wydzieleń krzemu powodując ich rozdrobnienie, częściową sferoidyzację i koagulację.

EN

In the paper are presented results of a research work concerning effects of various variants of heat treatment operations on mechanical properties of the EN AC-45000 (AlSi6Cu4) and AlSi17CuNiMg alloys, after homogenizing treatment, after dispersion hardening treatment, and after treatment consisting in combination of these two mentioned earlier treatments. Tests of the mechanical properties were performed on standardized specimens poured in metal moulds. The homogenizing had a significant effect on improvement of plasticity of the alloy, comparing to raw alloy, and therefore such treatment was performed before dispersion hardening, what enabled obtainment of increased elongation of the investigated alloys, maintaining very good mechanical properties (tensile strength Rm and hardness HB), referring to the alloy after standard T6 treatment (solution and artificial ageing treatment). Moreover, performed heat treatment had advantageous effect on shape of silicon precipitations, resulting in refining, partial spheroidizing and coagulation of the silicon precipitations.

2

Characterisation of nanostructured copper - WC materials

Stobrawa J. P., Rdzawski Z. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 32, nr 2

171-178

EN

Purpose: The aim of this work was to determine the microstructure and properties stability of nanocrystalline copper dispersion hardened with nanoparticles of tungsten carbides. Design/methodology/approach: Tests were made with Cu and Cu – WC micro – composites containing up to 3% of a hardening phase. The materials were fabricated by powder metallurgy techniques, including milling of powders, followed by their compacting and sintering. The main mechanical properties of the materials were determined from the compression test, and, moreover, measurements of the HV hardness and electrical conductivity have been made. Analysis of the initial nanocrystalline structure of these materials was made and its evolution during sintering was investigated. Findings: It was found that an addition of up to 1.5 wt % of a WC significantly improves mechanical properties of the material and increases its softening point. Research limitations/implications: The powder metallurgy techniques make it possible to obtain nanocrystalline copper-based bulk materials. Additional operations of hot extrusion are also often used. There is some threat, however, that during high temperature processing or application these materials this nanometric structure may become unstable. Practical implications: A growing trend to use new copper-based functional materials is observed recently world-wide. Within this group of materials particular attention is drawn to those with nanometric grain size. Originality/value: The paper contributes to the determination of WC nanoparticles content on the mechanical properties and the nanostructure stability of Cu-WC micro-composites.

3

Effect of dispersion hardening process on elongation of EN AB-43200 silumin

Pezda J.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 4

167-170

EN

Aluminum alloys belong to the second, after ferrous alloys, group of material having the biggest application in technology. Mass of metal structures is of important value, what involves lightweight mass of materials used in a given structure. Lightweight metals are used more and more often in metal structures, whereas aluminum and its alloys are the most widespread. Mechanical and technological properties of castings produced from Al-Si alloys depend on correct melting and pouring process, design of the castings and moulds and their heat treatments. Reduction of production costs requires selection of optimal parameters of the heat treatment (temperatures and durations of the treatments). The paper describes implementation of the ATD method to determination of hyperquenching and ageing treatments of EN AB-43200 (AK9) silumin. Investigated alloy was melted in electric resistance furnace. In the next stage the alloy underwent the treatment of refining and modification. Course of crystallization is presented with use of thermal-derivative analysis (ATD). That method was also used to determination of temperature range of heat treatments of the alloy. Obtained results apply to solidification curves recorded with use of the ATD method, light microscopy, strength tests and determination of an effect of heat treatment parameters on A5 elongation of the investigated alloy. On base of the performed tests of heat treated alloys there was determined an effect of selected parameters on obtained elongation (A5).

4

Determining the applicability of liquid alloy nitriding in fabrication of Al-AlN particle composites

Śleziona J., Dyzia M.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 3s

134--138

EN

One of the possible techniques of the fabrication of dispersion-hardened composites is by in situ reaction between the liquid alloy and gas. The study presents the results of the research on nitriding of liquid aluminium alloy containing Mg and Ti as alloying elements under the conditions of high pressure comprised in the range of 150-1000hPa at the temperature of up to 1100oC. It has been stated that under the applied conditions of the synthesis it is possible to obtain the AlN nitride, but it is formed on the liquid alloy surface and as a deposit on the surface of the crucible. Some results of the analysis of the phase constitution obtained in the fabricated products were presented along with the structure of these products.

5

Effect of selected microadditives on the mechanical properties of aluminium alloys

Rzadkosz S., Staszczak L.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 1

85-88

EN

iron in the process of solutioning and ageing of these alloys was described. Basing on the results of investigations, a comparative analysis was made to disclose the effect of low content (microadditives) of the elements, like Mn, Ti, Zr, B, Cr, Ni, Zn, Sn, Cd, In, Mg, Sb, and Ag on the primary structure of castings, mainly on the morphology of iron-bonding intermetallic phases. The studies also allowed for an effect of these elements on dispersion hardening of the examined alloys, reflected in an improvement of the principal mechanical properties (Rm, A5, HV), and on the kinetics of ageing. Tin, cadmium and indium, added in an amount of 0,1 – 0,15 %, were reported to have the strong-est effect on the process of dispersion hardening. Beneficial effect on the morphology of iron phases have manganese, chromium and nickel.

6

Analysis of ageing processes in squeeze cast Al-Zn-Cu-Mg alloys

Warmuzek M., Richert M., Mrówka G., Siwecki K.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

942-945

PL

W pracy przedstawiono wyniki badań procesu starzenia stopów Al-Zn-Cu-Mg, otrzymanych metodą prasowania w stanie ciekłym. Analizowano wpływ zawartości Mg i wstępnej, niewielkiej deformacji plastycznej po przesycaniu, na kinetykę utwardzenia dyspersyjnego, podczas starzenia w temperaturze 120 stopni Celsjusza. W pierwszych stadiach starzenia stwierdzono, na podstawie obserwacji mikroskopowych (TEM), powstawanie wydzieleń o morfologii stref GP, co stanowiło dominujący czynnik umocnienia stopów. Kolejne stadia wydzielania, związane z powstawaniem pośredniej fazy M' miały istotne znaczenie dla umocnienia stopów, poddanych starzeniu w przedłużonym czasie. Został zaobserwowany wpływ miedzi na przyspieszenie procesów wydzielania faz dyspersyjnych.

EN

In the paper the results of the examinations of the ageing processes of Al-Zn-Cu-Mg alloys, made by means of squeeze casting technology, were presented. The influence of Mg content and initial plastic deformation, after supersaturation, on the kinetics of dispersive hardening at 120 degrees centigrade was analysed. It was stated that at very early stages of ageing the formation of precipitates of GP zones formation could be considered a main hardening factor. The successive processes of intermediate phase M' precipitation played an important part during of ageing of examined alloys for longer time. The Cu effect on accelerating of the precipitation processes of disperse phase was observed.

7

Dispersion hardened Al-Me-SiC powders obtained by the mechanical alloying method.

Formanek B., Gierek A., Szopiński K.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1211-1214

EN

The mechanical alloying of Al-Ti-SiC and Al-Ni-SiC composite powders is presented in the article. The process parameters and morphology of powders were determined. The results allow to apply the agglomerated powders for sintering and thermal spraying processes.