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1

Analysis of Ballistic Resistance of Composites with EN AW-7075 Matrix Reinforced with Al2O3 Particles

Kurzawa A., Pyka A., Jamroziak K.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 1

73--78

EN

The paper presents the results of experimental-numerical tests of firing at aluminum composite materials. The test materials were manufactured by pressure infiltration of porous ceramic preforms made of α-Al2O3 particles in the amount of 30% and 40% by volume. The EN AW-7075 alloy was chosen as the material matrix, and the steel 7.62×39 mm (M 43) FMJ (Full Metal Jacket) intermediate ammunition was selected for firing. In the result of the experiment, the samples were perforated with a clear difference in the muzzle diameter. The projectile with fragments caused damage to up to three reference plates placed behind the samples (witness plates) in composites with 40% of particles by volume. The mechanics of crack propagation during ballistic impacts of the projectile was characterized based on microstructure studies. Then, using numerical analysis of impact load, the examination of composite materials puncture in the ABAQUS environment was carried out. The Finite Element Method (FEM) was employed for the discretization of geometric models using Hex elements. The Johnson-Cook constitutive model describing the relationship between stress and strain in metal-ceramic composites was applied for the analyses. Numerical models were then subjected to numerical verification using smoothed particle hydrodynamics (SPH). Based on the obtained results, it was found that the hybrid FEM/SPH method correlates significantly with the experimental results.

2

Właściwości materiałów kompozytowych na osnowie stopu aluminium EN AW-2024 i miedzi

Kurzawa A., Naplocha K., Kaczmar J. W.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2018

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z. 90 [298], nr 3

335--344

PL

W pracy zostały przedstawione wyniki badań wpływu umocnienia stopu EN AW-2024 cząstkami ceramicznymi α-Al2O3 oraz miedzi włóknami Saffil na wybrane właściwości mechaniczne. Materiały kompozytowe zostały wytworzone odlewniczą metodą infiltracji pod ciśnieniem preform ceramicznych charakteryzujących się porowatością otwartą. Stabilność termiczną oraz odporność na deformacje preform w trakcie procesu infiltracji zapewniono przez zastosowanie do ich budowy spoiwa krzemionkowego i odpowiedniej obróbki termicznej. W pracy, opierając się na badaniach struktury i analizy powierzchni przełomów badanych po wytrzymałościowych próbach technologicznych, wykazano wpływ umocnienia na mechanikę tworzenia złomu. Przeprowadzone badania wytworzonych materiałów potwierdziły ponadto ich bardzo dobre właściwości mechaniczne oraz eksploatacyjne, takie jak twardość i odporność na ścieranie, co tworzy zakres ich potencjalnych zastosowań w budowie środków transportu naziemnego.

EN

In this paper investigations of the strengthening effect of α-Al2O3 particles and Saffil alumina fibres on the EN AW-2024 aluminium alloy matrix as well as Cu based composites on selected mechanical properties were presented. The examined composite materials were produced by pressure infiltration of open porosity preforms. Thermal stability and resistance to deformation of the preforms during the infiltration were provided by using a silica binder for reinforcing their structure and appropriate heat treatment. On the basis of microstructure and surface analysis of fractures obtained during strength investigations the effect of reinforcement and crack development were demonstrated. Performed tests of manufactured materials have also confirmed their superior mechanical and service properties, such as hardness and abrasion resistance, which widens the scope of their potential application.

3

Metallographic analysis of piercing armor plate by explosively formed projectiles

Kurzawa A., Pyka D., Bocian M., Jamroziak K., Sliwinski J.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1686--1697

EN

This work discusses the impact consequences of Explosively Formed Projectiles (EFP) on the process of armor penetration. Based on the example of piercing shields made of armor steel ARMOX 370T with anti-vehicle mine of MPB type to verify the effectiveness of EFP charge. The influence of the projectile on the armor wall was analyzed on the basis of metallographic examination of the material from the armor, its plastic deformation and the change in the structure of the material within the shock influence area. As a result of the slug projectile impact on the armor surface a crater as a hole was formed with a diameter of approx. 105–120 mm, with noticeable traces of dynamic plastic deformation which occur at high speeds and high temperatures. In addition, microstructure analysis of the mines liner was performed, as in before and after piercing based on the analysis of EDS for phase precipitates identification.

4

Impact Strength of Composite Materials Based on EN AC-44200 Matrix Reinforced with Al2O3 Particles

Kurzawa A., Kaczmar J. W.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

73--78

EN

The paper presents the results of research of impact strength of aluminum alloy EN AC-44200 based composite materials reinforced with alumina particles. The research was carried out applying the materials produced by the pressure infiltration method of ceramic preforms made of Al2O3 particles of 3-6mum with the liquid EN AC-44200 Al alloy. The research was aimed at determining the composite resistance to dynamic loads, taking into account the volume of reinforcing particles (from 10 to 40% by volume) at an ambient of 23°C and at elevated temperatures to a maximum of 300°C. The results of this study were referred to the unreinforced matrix EN AC-44200 and to its hardness and tensile strength. Based on microscopic studies, an analysis and description of crack mechanics of the tested materials were performed. Structural analysis of a fracture surface, material structures under the crack surfaces of the matrix and cracking of the reinforcing particles were performed.

5

Compressive Strength of EN AC-44200 Based Composite Materials Strengthened with alpha-Al2O3 Particles

Kurzawa A., Kaczmar J. W.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 2

43--48

PL

The paper presents results of compressive strength investigations of EN AC-44200 based aluminum alloy composite materials reinforced with aluminum oxide particles at ambient and at temperatures of 100, 200 and 250oC. They were manufactured by squeeze casting of the porous preforms made of α-Al2O3 particles with liquid aluminium alloy EN AC-44200. The composite materials were reinforced with preforms characterized by the porosities of 90, 80, 70 and 60 vol. %, thus the alumina content in the composite materials was 10, 20, 30 and 40 vol.%. The results of the compressive strength of manufactured materials were presented and basing on the microscopic observations the effect of the volume content of strengthening alumina particles on the cracking mechanisms during compression at indicated temperatures were shown and discussed. The highest compressive strength of 470 MPa at ambient temperature showed composite materials strengthened with 40 vol.% of α-Al2O3 particles.

6

Bending Strength of EN AC-44200 – Al2O3 Composites at Elevated Temperatures

Kurzawa A., Kaczmar J. W.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

103--108

EN

The paper presents results of bend tests at elevated temperatures of aluminium alloy EN AC-44200 (AlSi12) based composite materials reinforced with aluminium oxide particles. The examined materials were manufactured by squeeze casting. Preforms made of Al2O3 particles, with volumetric fraction 10, 20, 30 and 40 vol.% of particles joined with sodium silicate bridges were used as reinforcement. The preforms were characterised by open porosity ensuring proper infiltration with the EN AC-44200 (AlSi12) liquid alloy. The largest bending strength was found for the materials containing 40 vol.% of reinforcing ceramic particles, tested at ambient temperature. At increased test temperature, bending strength Rg of composites decreased in average by 30 to 50 MPa per 100°C of temperature increase. Temperature increase did not significantly affect cracking of the materials. Cracks propagated mainly along the interfaces particle/matrix, with no effect of the particles falling-out from fracture surfaces. Direction of cracking can be affected by a small number of agglomerations of particles or of non-reacted binder. In the composites, the particles strongly restrict plastic deformation of the alloy, which leads to creation of brittle fractures. At elevated temperatures, however mainly at 200 and 300°C, larger numbers of broken, fragmented particles was observed in the vicinity of cracks. Fragmentation of particles occurred mainly at tensioned side of the bended specimens, in the materials with smaller fraction of Al2O3 reinforcement, i.e. 10 and 20 vol.%.

7

Mikrostruktura odlewniczych stopów magnezu wzmacnianych cząstkami AL2O3

Piórkowski P., Kurzawa A.

Technical Issues

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2016

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nr 3

99--105

EN

The article discusses problems of performing magnesium alloys composites, reinforced with Al2O3 particles. The chemical composition of casting magnesium alloys, most common alloy elements and their impact on alloy properties were described. The method of producing magnesium composites - „stir casting” and the impact of Al2O3 particles on properties of a composite were also described. Research were performed based on the AZ91D alloy for several different mixing times. The microstructure of an alloy and composite materials, including phases identification and quality of matrix-particle interphase were analysed. Based on the microstructure, the mixing efficiency was set. The percentage of Al2O3 particles in a composite was defined. The results of hardness and impact of mixing time on a microstructure and properties of a Mg-Al2O3 composite were shown.

8

Własności napoin na narzędziach rolniczych

Ambroziak A., Białucki P., Lange A., Kurzawa A., Kaszuba M., Janicki D.

Przegląd Spawalnictwa

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2016

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R. 88, nr 8

25--27

PL

Przedmiotem badań były napawane ostrza narzędzi maszyn rolniczych do uprawy gleby. W metodzie napawania płomieniowego użyto proszku stopowego na osnowie niklu w mieszaninie z różną zawartością proszku węglika wolframu. Badania polegały na wykonaniu pomiarów twardości, makro i mikrostruktury, analizy chemicznej napoiny i podłoża. W wyniku przeprowadzonych badań stwierdzono, że podczas napawania zachodzi częściowe rozpuszczanie się ziaren węglika wolframu w osnowie, co powoduje wzrost twardości warstwy. Ponadto, nie stwierdzono niekorzystnych zmian obniżenia twardości w stali w wyniku oddziaływania ciepła napawania. Twardość stali przed napawaniem wynosiła 36 HRC, a w strefie SWC 38-56 HRC. Badania metalograficzne ujawniły, że materiał proszku do napawania bardzo dobrze zwilża powierzchnie stali bez jej nadtopienia, w wyniku czego tworzy się z podłożem wyraźnie widoczna strefa dyfuzji.

EN

The subject of the study were surfaced blade tools of agricultural machinery for soil preparation. In the flame surfacing method was used alloy powder matrix of nickel in a mixture with different contents of tungsten carbide powder. The research involved making a measurement of hardness, macro and microstructure, chemical analysis of the deposit and the substrate. The results showed that while surfacing, partial dissolution of tungsten carbide grains in the matrix, which increases the hardness of the layer. In addition, no adverse changes to reduce the hardness of the steel by the heat surfacing. The hardness of the steel before hardfacing was 36 HRC, while in the zone SWC 38-56 HRC. Metallographic examination revealed that the powder during surfacing well wets the surfaces without melting the steel, thereby forming a substrate diffusion zone clearly visible.

9

Dodatek energetyczny i ryczałt na zakup opału – czyli kilka słów o wsparciu odbiorców wrażliwych

Kurzawa A.

Biuletyn Urzędu Regulacji Energetyki

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2016

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nr 3

8--15

10

Nowoczesne metody ilościowego określania stopnia zanieczyszczenia stopów aluminium

Hawranek R., Kurzawa A., Wójcik A.

Przegląd Odlewnictwa

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2014

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Vol. 64, nr 11-12

464--467

PL

Zanieczyszczenia zawarte w ciekłym metalu i problemy związane z ich wykrywaniem i eliminacją są wciąż jednym z głównych powodów wad odlewniczych, brakowania całych serii produkcyjnych, kosztów reklamacji i „obsługi” klienta. Zaplanowanie odpowiedniego procesu wytopu ciekłego metalu, surowe przestrzeganie wytyczonych procedur oraz ciągła kontrola stanu czystości ciekłego stopu w piecu jest obecnie koniecznością w nowoczesnej odlewni dążącej do ciągłej poprawy procesu, zmniejszania poziomu braków oraz konkurującej o produkcję wysokojakościowych detali. W artykule zostały zaprezentowane i omówione nowoczesne techniki oraz urządzenia do pomiaru zawartości zanieczyszczeń w ciekłych stopach aluminium w warunkach produkcyjnych odlewni. Specyfikacja techniczna, instrukcje, warunki i koszty poszczególnych urządzeń są udostępniane przez producentów danych instrumentów. Celem artykułu było przedstawienie dostępnych obecnie technik i instrumentów badawczych do określania poziomu zawartości zanieczyszczeń niemetalicznych w ciekłych stopach aluminium a także zestawienie metod badawczych i zakresu otrzymywanych wyników a nie komercyjna prezentacja rozwiązań proponowanych przez różnych dostawców.

EN

Contaminations contained in liquid metal and problems related to their revealing and eliminating are still one of the main reasons of casting defects, whole production series being sorted out as defected, costs of claims and clients ‘servicing’. Planning the proper melting process of liquid metal, strict adhering to guidelines of procedures and a constant purity control of liquid alloy in a furnace is necessary in a modern casting house striving after a continuous process improvement, lowering the defects level as well as competing in production of high quality details. New, modern techniques and devices for measuring contaminations in liquid aluminium alloys under casting production conditions are presented and discussed in the hereby paper. Technical specifications, instructions, conditions and costs of individual devices are made available by producers of these equipment. The presentation of currently available techniques and investigation instruments - useful in determining non-metallic contaminations in liquid aluminium alloys - as well as the list of investigation methods and the range of obtainable results, not the commercial presentation of solutions proposed by various suppliers, was the aim of the paper.

11

Physical Properties of Copper Based MMC Strengthened with Alumina

Kaczmar J. W., Granat K., Kurzawa A., Grodzka E.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 2

85--90

EN

The aim of this work is the development of Cu-Al2O3 composites of copper Cu-ETP matrix composite materials reinforced by 20 and 30 vol.% Al2O3 particles and study of some chosen physical properties. Squeeze casting technique of porous compacts with liquid copper was applied at the pressure of 110 MPa. Introduction of alumina particles into copper matrix affected on the significant increase of hardness and in the case of Cu-30 vol. % of alumina particles to 128 HBW. Electrical resistivity was strongly affected by the ceramic alumina particles and addition of 20 vol. % of particles caused diminishing of electrical conductivity to 20 S/m (34.5% IACS). Thermal conductivity tests were performed applying two methods and it was ascertained that this parameter strongly depends on the ceramic particles content, diminishing it to 100 Wm-1K-1 for the composite material containing 30 vol.% of ceramic particles comparing to 400 Wm-1K-1 for the unreinforced copper. Microstructural analysis was carried out using SEM microscopy and indicates that Al2O3 particles are homogeneously distributed in the copper matrix. EDS analysis shows remains of silicon on the surface of ceramic particles after binding agent used during preparation of ceramic preforms.

12

Własności trybologiczne materiałów kompozytowych na bazie stopów EN AW-2024 i EN AW-7075

Kurzawa A., Granat K., Grodzka E., Naplocha K., Kaczmar J. W.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 1 spec.

97--102

PL

W pracy zostały przedstawione wyniki badań intensywności zużycia ściernego materiałów kompozytowych na bazie stopów EN AW-2024 i EN AW-7075 umacnianych cząstkami ceramicznymi Al2O3. Materiały zawierające 10÷40%obj. cząstek umacniających wytworzone metodą squeeze casting poddano ścieraniu z zastosowaniem metody pin-on-disc. Pozytywny efekt wzrostu odporności na zużycie ścierne potwierdzono dla materiałów opartych na stopie 7075 umocnionych od 10 do 30%obj. Al2O3. Umocnienie cząstkami stopu 2024, chociaż nieznacznie podniosło ich odporność na ścieranie przy zawartościach objętościowych cząstek ceramicznych 10 i 20% obj. to nie jest jednak satysfakcjonujące. Siła docisku próbki wpływa w zasadniczy sposób na intensywność zużycia materiałów kompozytowych. Pod mniejszym ciśnieniem 0,2 MPa pomiędzy próbką a tarczą materiały kompozytowe wykazały ok. 2-3 krotnie większą odporność na zużycie w porównaniu do stopu nieumocnionego. Zwiększenie ciśnienia do 1,0 MPa i 1,2 MPa spowodowało zwiększenie szybkości zużycia próbek, w szczególności dla materiałów zawierających 40% obj. cząstek Al2O3. Materiały kompozytowe na osnowie stopu AW-2024 generowały o ok 20÷25% większe opory tarcia od materiałów wytworzonych na osnowie stopu AW-7075. W wyniku analizy powierzchni ścierania stwierdzono, że wraz ze wzrostem zawartości objętości cząstek umacniających zmieniał się charakter zużycia z mieszanego, adhezyjno-ściernego występującego w kompozytach z 10% obj. cząstek Al2O3 w typowo ścierne występujące w materiałach zawierających 40% obj. udział umocnienia. Stopień zużycia przeciwpróbki silnie zależał od użytego materiału osnowy. Pomimo że stop nieumocniony AW-2024 wpływał na zużycie żeliwnej tarczy wolniej od stopu AW-7075, to jednak w materiałach zawierających umocnienie tendencja była odwrotna. Chropowatość Ra dna rowka przeciwpróbki potwierdza głębsze bruzdowanie przy ścieraniu kompozytów wytworzonych na osnowie stopu AW-2024. Największą chropowatość wykazały powierzchnie tarcz na których ścierano próbki z zawartością 10% obj. cząstek. Wraz ze wzrostem udziału cząstek w materiałach kompozytowych chropowatość przeciwpróbki maleje.

13

Effect of nickel equivalent on austenite transition ratio in Ni-Mn-Cu cast iron

Janus A., Kurzawa A.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 2

53--58

EN

Determined was quantitative effect of nickel equivalent value on austenite decomposition degree during cooling-down castings of Ni-Mn- Cu cast iron. Chemical composition of the alloy was 1.8 to 5.0 % C, 1.3 to 3.0 % Si, 3.1 to 7.7 % Ni, 0.4 to 6.3 % Mn, 0.1 to 4.9 % Cu, 0.14 to 0.16 % P and 0.03 to 0.04 % S. Analysed were castings with representative wall thickness 10, 15 and 20 mm. Scope of the examination comprised chemical analysis (including WDS), microscopic observations (optical and scanning microscopy, image ana-lyser), as well as Brinell hardness and HV microhardness measurements of structural components.

14

Bending strength and fracture investigations of Cu based composite materials strengthened with \delta-alumina fibres

Kaczmar J. W., Granat K., Naplocha K., Kurzawa A., Grodzka E., Samociuk B.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 2

59--63

EN

Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu – 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300ºC the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

15

The effect of α-alumina particles on the properties of EN AC-44200 Al alloy based composite materials

Kaczmar J. W., Kurzawa A.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 1

39--44

EN

Purpose: The unreinforced EN AC-44200 aluminium alloy is characterized by the medium mechanical properties and the purpose of performed investigations was improvement of mechanical properties of this alloy by introducing stable ceramic α-alumina particles. Design/methodology/approach: The composite materials were manufactured by squeeze casting of porous ceramic preforms characterized by the open porosities of 90%, 80%, 70% and 60% with the liquid EN AC-44200 aluminum alloy. The composite materials containing 10 vol. %, 20 vol. %, 30 vol. % and 40 vol. % were manufactured and characterized by the homogeneous distribution of alumina particles in the matrix. On the base of microscopic investigations there was ascertained good bonding at the interface matrix/ strengthening particles. Findings: Manufacturing of porous ceramic preforms from alumina powders characterized by the desired open porosity was elaborated. After squeeze casting with liquid EN AC-44200 alloy there was noticed considerable increase of physical and mechanical properties: hardness HB increased from 82 HB for unreinforced alloy to 150 HB for material containing 40 vol. % of particles. There was noticed increase of tensile strength, bending strength and compression strength, although what is typical for composite materials, decrease of impact strength. Research limitations/implications: There was noticed small rest porosity with decreasing porosity of the ceramic preforms. Further investigations on porosity removal basing on modification of production parameters are forseen. Practical implications: Reinforcing of EN AC-44200 aluminum alloy with ceramic particles is effective taking into account increase of hardness and strength (tensile, bending, compression), although the relatively low impact strength can be restriction for the applications of these materials as the elements subjected to dynamic loads. Originality/value: Manufactured materials can be applied as elements subjected to static loads and the relatively large specific strength allow to diminish the weight of elements applied in the construction of means of transportation.

16

Tribological properties of Cu based composite materials strengthened with Al2O3 particles

Kaczmar J., Granat K., Grodzka E., Kurzawa A.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 2s

33--36

EN

In the present work copper was strenghtened with 20 and 30 vol. % of alumina particles characterized by diameter of 3-6μm. The copper based composite materials were manufactured by the squeeze casting method. Preheated preforms made from Al2O3 particles were placed in the desired place in the heated cast die and the squeeze casting process with liquid copper was performed applying the infiltration pressure of 90MPa and pressure was kept for 10-15s until solidification was complete. The microstructure and physical properties: Brinell hardness (HBW) and density were characterized. Metallografic examinations showed that alumina particles were uniformly distributed in the copper matrix. Hardness of 208 HBW for composite materials containing 30 vol.% of particles was achieved. Wear investigations were performed applying the tribological pin-on-disc tester. Friction forces between copper based composite materials containing 20 and 30 vol. % of Al2O3 particles and cast iron were registered and wear was determined on the base of the specimen mass loss after 1.0, 3.5 and 8.5 km friction distance.

17

Tribological properties of AC44200 based composites strenghead with Al2O3 particles

Kurzawa A., Grodzka E., Janus A., Kaczmar J. W.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2

69-74

EN

The paper presents a research on abrasion resistance of aluminium-based composites consisting of EN AC-44200 matrix reinforced with Al2O3 particles. The examinations revealed that wear intensity of the composites decreased with increasing volume fraction of the particles. Much more intensive abrasive wear was observed on the first kilometre in comparison to the wear on the subsequent distances, i.e. from 1 to 3.5 km and from 3.5 to 8.5 km of the wear distance. Microscopic examinations permitted determining the way and type of wear occurring in the examined materials. In the case of the AC-44200 matrix, typical adhesive wear is observed. In composite materials however, abrasive wear prevails over adhesive wear. Increased volume fraction of Al2O3 particles in composite materials results in increasing friction factor in average by 0.250 per each 10 vol.%. Wear of the cast-iron counterspecimen is also strongly dependent on volume fraction of the reinforcing particles. The counterspecimen demonstrates the largest wear when working in contact with a composite material containing 40 vol.% of Al2O3 particles.

18

Effect of alloying elements on solidification of primary austenite in Ni-Mn-Cu cast iron

Janus A., Kurzawa A.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2 spec.

93--96

EN

Within the research, determined were direction and intensity of alloying elements influence on solidification way (directional or volumetric) of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu. 50 cast shafts dia. 20 mm were analysed. Chemical composition of the alloy was as follows: 1.7 to 3.3 % C, 1.4 to 3.1 % Si, 2.8 to 9.9 % Ni, 0.4 to 7.7 % Mn, 0 to 4.6 % Cu, 0.14 to 0.16 % P and 0.03 to 0.04 % S. The discriminant analysis revealed that carbon influences solidification of primary austenite dendrites most intensively. It clearly increases the tendency to volumetric solidification. Influence of the other elements is much weaker. This means that the solidification way of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu does not differ from that in an unalloyed cast iron.

19

Badania wytrzymałości na ściskanie materiałów kompozytowych na osnowie stopu AW-AlCu4Mg2Mn umacnianych cząstkami SiC

Kurzawa A., Kaczmar J. W.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2 spec.

139--142

PL

W pracy przedstawiono wyniki badań wytrzymałości na ściskanie materiałów kompozytowych na osnowie stopu AW-AlCu4Mg2Mn. Materiały do badań zostały wytworzone metodą infiltracji pod ciśnieniem stopem AW-AlCu4Mg2Mn porowatych kształtek ceramicznych wykonanych z cząstek SiC o wielkości 6÷10μm. Praca zawiera analizę przebiegu σ-ε materiałów kompozytowych dla zawartości cząstek SiC wynoszących 10, 20, 30% obj. oraz stopu nieumocnionego. Ponadto przedstawiono analizę mikroskopową powierzchni złomów próbek w płaszczyźnie równoległej do działania siły ściskającej. Wykazano, że badane kompozyty charakteryzują się wyraźnym zmniejszeniem wartości odkształcenia plastycznego wraz ze wzrostem zawartości cząstek umacniających. Materiały nieumocnione w całym zakresie odkształceń wykazują znaczną plastyczność. W przypadku materiałów zawierających 10%obj. SiC w zakresie odkształceń plastycznych następuje nieznaczne umocnienie materiału. Wprowadzenie większej objętości cząstek umacniających do materiałów kompozytowych powoduje znaczne zmniejszenie plastyczności materiałów. Próbki z materiałów o objętości 20 i 30%obj. cząstek SiC ulegają kruchemu pękaniu przy znacznie większych wartościach naprężeń σ.

EN

In this paper strength tests of composite materials based on AW-AlCu4Mg2Mn obtained in uniaxial compression test was studied. Materials used for examination were made from AW-AlCu4Mg2Mn alloy and porous preforms of SiC particles (grain size 6÷10μm) by pressure infiltration (squeeze casting). The stress-strain curves of the materials with 10% vol., 20% vol., 30% vol. particles of SiC, as well unreinforcement alloy and microstructure of scrap surface samples in a plane parallel to the compressive force were analyzed. The investigated metal matrix composites are characterized by marked reduced the plastic strain values with increasing particle strengthening while the unreinforcement materials throughout the range of deformation show considerable plasticity. In the case of the material containing 10% vol of SiC the plastic strain is a slight strengthening of the material. With increasing of the particle content the plasticity decreases. Materials with 20%vol and 30%vol of SiC particles were brittle cracked at much higher values of stress σ.

20

Structure and properties of porous ceramic preforms made of α-alumina particles

Kaczmar J. W., Kurzawa A.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

157--162

EN

Properties of ceramic preforms made of α-alumina particles for strengthening of metal based composite materials manufactured by squeeze casting are discussed in the paper. Composite materials strengthened with ceramic particles can be then plastically worked in order to remove the residual porosity and give the final net shape. There was investigated the permeability of porous preforms as the measure of the open porosity making possible the infiltration process with the molten metal, compression strength, bending strength and shear strength determining the stability of porous ceramic preforms during infiltration. Performed investigations allow to ascertain the occurrence of the open porosity in the porous preforms and strong effect of porosity on permeability. The largest permeability of 19 m2/Pa•s showed porous preforms characterized by porosity the of 90%. The strength properties increased with the decrease of preforms porosity and the prerforms characterized by 60% of porosity were characterized by the largest strength properties (bending strength Rg =7 MPa, compression strength Rc = 11.5 MPa, shear strength Rt = 4.0 MPa). The microscopic observations of fractures surfaces allow to evaluate quality and forming phenomena of the binder bridges connecting the ceramic particles.