Wyniki wyszukiwania - BazTech

1

Wpływ parametrów obróbki cieplnej na właściwości stopu aluminium 7075

Jaśkiewicz K.

Hutnik, Wiadomości Hutnicze

|

2018

|

Vol. 85, nr 8

271--273

PL

Artykuł obejmuje analizę badań eksperymentalnych dotyczących wpływu obróbki cieplnej na właściwości blach ze stopu aluminium 7075. Głównym obiektem badań był proces utwardzania dyspersyjnego, na który składają się operacje: przesycania i starzenia wydzieleniowego. Podjętym w pracy celem, było określenie zależności właściwości mechanicznych (twardości) stopu aluminium 7075 od czasu wytrzymania przy założonej temperaturze podczas procesu przesycania. Na podstawie zebranych danych wyznaczono minimalne czasy grzania dla procesu przesycania, przy których możliwe jest zastosowanie kształtowania plastycznego, a następnie przeprowadzenie obróbki sztucznego starzenia w celu uzyskania odpowiednich właściwości mechanicznych.

EN

The article contains the analysis of experimental studies on the influence of heat treatment on the properties of aluminum 7075 sheet metal. The main object of the research was the dispersion hardening process, which consists of the operations of solutioning and artificial aging. The aim at the work was to determine the dependence of the mechanical properties (hardness) of the aluminum alloy 7075 from the time it was held at the assumed temperature during the solutioning. Based on the collected data determined the minimum times for the solutioning process at which plastic forming can be applied and then the artificial aging treatment to obtain the appropriate mechanical properties are determined.

2

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

Jarco A.

Inżynieria Maszyn

|

2017

|

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.

3

Nanocrystalline copper based microcomposites

Stobrawa J. P., Rdzawski Z.M., Głuchowski W., Domagała-Dubiel J.

Journal of Achievements in Materials and Manufacturing Engineering

|

2012

|

Vol. 54, nr 1

49--57

EN

Purpose: The aim of this work was to investigate microstructure, mechanical properties and deformation behavior of copper microcomposites: Cu- Y2O3, Cu- ZrO2 and Cu-WC produced by powder metallurgy techniques. Design/methodology/approach: Tests were made with Cu-Y2O3, Cu-ZrO2 and Cu-WC microcomposites containing up to 2% of a strengthening 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, additionally, measurements of HV hardness and electrical conductivity were made. Analysis of the initial nanocrystalline structure of these materials was made and its evolution during sintering and cold deformation was investigated. Findings: It was found out that addition of up to 2 wt.% of a strengthening phase significantly improves mechanical properties of the material and increases its softening point. The obtained strengthening effect have been discussed based on the existing theories related to strengthening of nanocrystalline materials. The studies have shown importance of “flows” existing in the consolidated materials and sintered materials in pores or regions of poor powder particle connection which significantly deteriorate the mechanical properties of micro-composites produced by powder metallurgy. Research limitations/implications: The powder metallurgy techniques make it possible to obtain copper-based bulk materials by means of input powder milling in a planetary ball mill, followed by compacting and sintering. Additional operations of hot extrusion are also often used. There is some danger, however, that during high-temperature processing or application of these materials at elevated or high temperatures this nanometric structure may become unstable. Practical implications: A growing trend to use new copper based microcomposites is observed recently world-wide. Within this group of materials particular attention is put to those with nanometric grain size of a copper matrix, which show higher mechanical properties than microcrystalline copper. Originality/value: The paper contributes to the knowledge of mechanical properties and the nanostructure stability of Cu-Y2O3, Cu-ZrO2 and Cu-WC microcomposites. A controlled process of milling, compacting, sintering and cold deformation provides possibility to obtain nanocrystalline copper based materials with improved functional properties.

4

Characterisation of nanostructured copper - WC materials

Stobrawa J. P., Rdzawski Z. M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

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.

5

Improvement of Structure and Properties of Cast Ferrite-Pearlite Steels for Freight Railway Cars

Rabinovich A., Bublikov Y., Tregubenko G., Polyakov G., Puchikov A., Uzlov O.

Archives of Foundry Engineering

|

2008

|

Vol. 8, iss. 1 spec.

295--298

EN

As it is known for increasing of properties (YTS ≥ 380 MPa) of cast steels it is effective to increase content of substitutional alloying elements, (Si, Mn, Cr, Ni). However it leads to rising in price of Steel ton. Increasing of Si and Mn content only is limited by decreasing of ductility and weld ability. As a rule Silicon content at these steels is not higher than 0.4-0.6% and Si:Mn ratio is not higher than 1:2. Now for grain refinement uses inoculation of steel by nitrogen and elements with high chemical affinity to nitrogen. Mostly vanadium is used, however niobium sometime is used. Disadvantages of this are high cost of alloying elements and low thermodynamic stability of vanadium and niobium nitrides. Particles of V(C, N) and Nb(C, N) dissolve during heating for heat treatment or during welding. It leads to decreasing of grain refinement effect. Adaptation of this microalloying strategy for casts producing for freight railway cars let estimate possibility of application these casts in a new generation freight railway cars.

PL

Celem przedstawionych badań jest analiza możliwości zastosowania utwardzania węglikowo-azotkowego staliwa zawierającego 0,2% C w celu zapewnienia możliwości zastosowania tego materiału do celów wykonania odpowiedzialnych odlewów kolejowych. Metoda wykorzystania mikrododatków stopowych, znana w produkcji wyrobów walcowanych, została zaadaptowana do produkcji odlewów kolejowych części wagonów towarowych nowej generacji. Wykonano serię wytopów doświadczalnych, na podstawie których otrzymano zakresy stężeń pierwiastków bazowych i dodatków modyfikujących.

6

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

Pezda J.

Archives of Foundry Engineering

|

2008

|

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).

7

Odpadowe materiały mineralne w przegrodach przeciwfiltracyjnych

Kledyński Z., Falaciński P., Machowska A.

Nowoczesne Budownictwo Inżynieryjne

|

2007

|

Nr 6

68--73

8

Effect of selected microadditives on the mechanical properties of aluminium alloys

Rzadkosz S., Staszczak L.

Archives of Foundry Engineering

|

2007

|

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.