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Manufacturing of Composite Castings by the Method of Fused Models Reinforced with Carbon Fibers Based on the Aluminum Matrix

Szymański Paweł

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

118--123

EN

The paper presents an attempt to produce aluminum matrix composites reinforced with short carbon fibers by precision casting in a chamber with a pressure lower than atmospheric pressure. The composite casting process was preceded by tests related to the preparation of the reinforcement. This is related to the specificity of the precision casting process, in which the mold for shaping the castings is fired at a temperature of 720°C before pouring. Before the mold burns, the reinforcement must be inside, while the carbon fiber decomposes in the atmosphere at 396°C. In the experiment, the reinforcement in the form was secured with flake graphite and quartz sand. The performed firing procedure turned out to be effective. The obtained composite castings were evaluated in terms of the degree of alloy saturation and the displacement of carbon fibers. As a result of the conducted tests, it was found that as a result of unfavorable arrangement of fibers in the CF preform, the flow of metal may be blocked and porosity may appear in the casting.

2

In-situ metal matrix composites development for additive manufacturing: a perspective

Essien U. A., Vaudreuil S.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 111, nr 2

78--85

EN

Purpose: This paper presents an overview on some ceramic materials capable of achieving in-situ reinforcements in Al/Al-alloy metal matrix composites (MMCs) during laser processing. It also presents perspective on further exploitation of the in-situ reinforcement capabilities for high quality MMCs feedstock material development. Design/methodology/approach: The approach utilized in writing this paper encompasses the review of relevant literature on additive manufacturing (AM) of MMCs. Findings: It is widely accepted that the in-situ reinforcement approach has proven to be more advantageous than the ex-situ approach. Though there are still some challenges like the formation of detremental phases and the evaporation of low melting temperature elements, the in-situ reinforcement approach can be used to tailor design composite powder feedstock materials for the AM of MMCs. The preprocessing or tailor-designing in-situ metal matrix composite powder before laser melting into desired components holds more promises for metal additive manufacturing. Practical implications: The need for the development of MMCs powder feedstock that can be directly fabricated using suitable AM technique without prior powder processing like blending or mechanical alloying has not yet been addressed Therefore, having a pre-processed in-situ reinforced MMC feedstock powder can encourage easy fabrication of MMC and other advantages of AM technologies powder recycling. Originality/value: The idea explained in this article is relevant to materials development for AM processing of metal matrix composite. This paper has pointed out future trends for MMCs materials feedstock powder development and new ideas for further exploitation of MMCs and AM technologies. The advantages of tailor-designing composite powders other than merely mixing them has been emphasized.

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Effect of Zeolite Addition on the Production of a Cast Porous Composite Based on AC-AlSi11 Silumin

Borowiecka-Jamrożek Joanna, Kargul Marcin

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

96--101

EN

The paper presents the application of the casting method for the production of porous composites, called syntactic foams, of the casting alloy - solid particles type. This method was used to produce composites based on Al alloys reinforced with particles of clinoptilolite, a natural mineral from the zeolite group. Before the casting process, tests were carried out on the morphology, physicochemical properties and chemical composition of the zeolite, which was obtained from a rock called zeolite tuff, mined in a quarry in Kucin, (VSK PRO-ZEO s.r.o., Slovakia). Observations of the microstructure of the produced composites were also carried out using a scanning electron microscope. Diffractometric tests of zeolite rock as delivered for research and of the produced samples reinforced with zeolite particles were also carried out. Initial studies of the density and porosity of the produced composites were performed. The usefulness of the presented method of composite production was assessed on the basis of the conducted structural tests, with particular emphasis on the particle distribution in the alloy matrix.

4

Tailoring the mechanical properties of hypereutectic in situ Al–Mg2Si composites via hybrid TiB2 reinforcement and hot extrusion

Moazami Mohammad Rasool, Razaghian Ahmad, Mirzadeh Hamed, Emamy Massoud

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e87, 1--9

EN

Microstructure and mechanical properties of Al-15Mg 2 Si-xTiB 2 hybrid composites in the as-cast and wrought conditions were studied. TiB 2 addition led to a significant refinement and modification of primary Mg2Si particles (up to 3 wt% TiB 2 addition) via the heterogeneous nucleation mechanism, which improved the as-cast tensile properties. Further additions led to the appearance of coarse needle-shaped Al 3Ti particles with the consequent deterioration of tensile properties. Hot deformation by extrusion process and elevated-temperature exposure resulted in the fragmentation, dispersion, and spheroidization of pseudo-eutectic Mg 2 Si constituents, which led to a significant enhancement of tensile properties. The ultimate tensile strength of the extruded Al-15Mg 2 Si-3TiB 2 composite was 285 MPa with the total elongation of ~ 8%, which revealed a good strength-ductility balance. The corresponding value for the as-cast Al-15Mg 2 Si composite was only 198 MPa%. Accordingly, this study revealed that the presence of optimum amount of TiB 2 combined with high-temperature thermo-mechanical processing could remarkably improve the mechanical properties of the hypereutectic Al-Mg-Si composites in terms of strength-ductility balance, quality index, and tensile toughness.

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Experimental investigation and optimization of mechanical properties of nitinol reinforced composites

Kalepu Sambasivarao, Nallu Ramanaiah

Composites Theory and Practice

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2021

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R. 21, nr 4

154--160

EN

Metal matrix composites (MMCs) have elevated properties when compared to their parent metals. Aluminium, due to its light weight has a versatile set of applications. In the present work, the 2024 aluminium alloy was chosen as the metal matrix, was melted and stir cast at a temperature of around 900°C along with an addition of a nickel-titanium (Ni-Ti) in powder form as the reinforcement in varying proportions (2, 4, 6, 8% weight fractions). Tests were conducted to analyse the tensile strength, impact strength, elongation and microstructure of the produced specimens. SEM micrographs revealed that the MMCs with 2 and 4 wt.% reinforcement exhibited better dispersion of the reinforcement. The composites having the 4 and 6 wt.% additions of Ni-Ti powder exhibited better ultimate tensile strength when compared to the other specimens, whereas the one with the 8 wt.% addition of Ni-Ti powder revealed better impact strength. Some agglomerations of the Ni-Ti particles were observed on the fractured surface. When evaluating the optimum result using design expert or the design of experiments, it is understood that when the data points are evenly split, either transformation or a higher order model can improve the fit to obtain the optimum result. The yield strength of the metal matrix composite which indicates the ability of the material to withstand permanent deformation varies with respect to the additions of Ni-Ti powder. It occurred that the MMCs with the 4 and 6 wt.% reinforcement produced better results when compared with the 2 and 8 wt.% ones, respectively. The impact strength of the composite containing the 8 wt.% addition exhibited better resistance when compared with the 2, 4 and 6 wt.% reinforced MMCs. It was revealed that the 8 wt.% addition of Ni-Ti powder to the metal matrix resisted fracture due to the applied load. The lower limit for the ultimate tensile strength is 186 MPa and for the upper limit it is 212.14 MPa, which are within the acceptable range; therefore, the optimum results are within the limits.

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Effect of Temperature on the Structure and Mechanical Properties of Mechanically Alloyed Al-NiO Composite

Zygmunt-Kiper M., Blaz L, Sugamata M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 1

121--126

EN

Mechanical alloying of high-purity aluminum and 10 wt.% NiO powders combined with powder vacuum compression and following hot extrusion method was used to produce an Al-NiO composite. Mechanical properties of as-extruded materials as well as the samples annealed at 823 K /6 h, were tested by compression at 293 K - 770 K. High mechanical properties of the material were attributed to the highly refined structure of the samples. It was found that the structure morphology was practically not changed during hot-compression tests. Therefore, the effect of deformation temperature on the hardness of as-deformed samples was very limited. The annealing of samples at 823 K/6 h induced a chemical reaction between NiO-particles and surrounding aluminum matrix. As a result, the development of very fine aluminum oxide and Al3Ni grains was observed.

PL

Kompozyt na osnowie aluminium zawierający dodatek 10% mas. NiO wytworzono metodą mechanicznej syntezy stosując mielenie proszków aluminium i tlenku niklu oraz mechaniczną konsolidację uzyskanego proszku metodą prasowania próżnio- wego i wyciskania w temperaturze 673 K Własności mechaniczne uzyskanego kompozytu, jak również próbek wyżarzonych w 773 K/6 godz., badano w zakresie 293 K-770 K w próbie ściskania. Badania strukturalne wykazały silne rozdrobnienie skład- ników strukturalnych zarówno w materiale wyciskanym, jak również w próbkach wyżarzonych, co jest przyczyną wysokich własności mechanicznych uzyskanego kompojrytu. W przypadku próbek odkształcanych „na gorąco” praktycznie nie obserwuje się istotnych zmian morfologii struktury. Jednakże wyżarzanie w 823 K/6 godz. spowodowało zmiany strukturalne wywołane reakcją chemiczną między cząstkami NiO a osnową, której skutkiem było utworzenie silnie dyspersyjnych wydzieleń tlenku aluminium i ziam fezy międzymetalicznej typu AI3Ni.

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The effect of sintering temperature,sintering time and reinforcement particle size on properties of Al-Al2O3 composites

Konieczny M.

Composites Theory and Practice

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2012

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R. 12, nr 1

39-43

EN

The main aim of this paper was to investigate the effect of sintering temperature, sintering time and reinforcement particle size on the properties of Al-Al2O3 composites. Three sintering temperatures were applied: 500, 550 and 600 °C for 30, 60 and 90 minutes. Experiments were performed using specimens containing 0, 5 and 10% of alumina. The average particle sizes of alumina were 2, 10 and 20 μm. The investigated properties included relative density, hardness and compressive strength. Microstructural observations showed that Al-Al2O3 composites could be successfully formed for all of the studied combinations of sintering temperature, sintering time, alumina particle sizes and amount of reinforcement. The relative density of all the composites increased when the particle size of alumina was reduced. The highest relative density was obtained at 600 °C. Higher hardness and compressive strength were observed in samples containing finer Al2O3 particles. The variations in hardness and compressive strength of Al-Al2O3 composites were dependent on the sintering temperature and time. Increasing sintering time at 500 and 550 °C led to a gradual increase in hardness and compressive strength. Similar results were obtained as well after sintering at 600 °C when the sintering time was increased up to 60 minutes. A prolonged sintering time up to 90 min had a contrary effect on the hardness and compressive strength of the composites.

PL

Głównym celem badań było przeanalizowanie wpływu temperatury spiekania, czasu spiekania oraz wielkości cząstek zbrojących na własności kompozytów Al-Al2O3. Zastosowano trzy temperatury spiekania: 500, 550 i 600°C oraz trzy czasy: 30, 60 oraz 90 minut. Eksperymenty prowadzono na próbkach wykonanych ze spiekanego proszku aluminium oraz na próbkach zawierających dodatkowo 5 i 10% tlenku glinu. W badaniach używano proszku Al2O3 o trzech wielkościach cząstek: 2, 10 oraz 20 μm. Badano wpływ parametrów wytwarzania kompozytów na ich gęstość względną, twardość oraz wytrzymałość na ściskanie. Obserwacje mikroskopowe wykazały, że kompozyty Al-Al2O3 mogą być skutecznie wytwarzane przy zastosowaniu wszystkich użytych kombinacji temperatury spiekania, czasu spiekania oraz zastosowanych ilości oraz wielkości cząstek zbrojących. Gęstość względna kompozytów wzrastała wraz ze zmniejszaniem się wielkości zastosowanych cząstek Al2O3. Najwyższą względną gęstość otrzymano dla kompozytów spiekanych w temperaturze 600°C. Wyższa twardość oraz wyższa wytrzymałość na ściskanie była uzyskiwana w próbkach zawierających mniejsze cząstki tlenku glinu. Zmiany twardości i wytrzymałości na ściskanie były uzależnione od czasu oraz temperatury spiekania. Wzrost czasu spiekania w temperaturach 500 oraz 550°C prowadził do stopniowego wzrostu twardości oraz wytrzymałości na ściskanie. Podobne rezultaty otrzymano także po spiekaniu w temperaturze 600°C, gdy czas spiekania był krótszy niż 60 minut. Jednak wydłużenie czasu spiekania do 90 minut spowodowało spadek twardości oraz wytrzymałości na ściskanie.

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Struktura i właściwości kompozytów zawierających węgiel szklisty

Myalski J.

Inżynieria Materiałowa

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2003

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R. XXIV, nr 6

655-658

PL

W artykule przedstawiono wyniki badań dotyczące właściwości nowej grupy materiałów kompozytowych z osnową metaliczną. Cechą charakterystyczną, wyróżniającą te kompozyty jest wykorzystanie do umocnienia dotychczas nie stosowanych jako zbrojenie cząstek węgla o struktrze amorficznej. Było to spowodowane interesującymi z punktu widzenia właściwości cechami węgla szklistego, do których zaliczyć można dobre właściwości tribologiczne, cieplne oraz mechaniczne. Cząstki wprowadzono do ciekłego metalu osnowy metodą mechanicznego mieszania. Cząstki przed wprowadzeniem do ciekłego metalu pokryto warstwami ochronnymi zapobiegającymi procesom destrukcji termicznej i pozwalającymi na równomierne rozmieszczenie cząstek w osnowie zwiększającym zwilżalność cząstek. Oceny wpływu rodzaju pokrycia na strukturę i właściwości kompozytu dokonano na podstawie badań podstawowych właściwości mechanicznych i tribologicznych. Na podstawie badań wytrzymałościowych stwierdzono, że dodatek cząstek węgla amorficznego powoduje obniżenie zarówno wytrzymałości na rozciąganie oraz udarności. Natomiast korzystnie zmienia właściwości tribologiczne, powodując znaczne obniżenie współczynnika tarcia i zmniejszenie zużycia kompozytu oraz materiału przeciwpróbki.

EN

The paper presents results of investigations devoted properties of new group of metal matrix composite. Characteristic feature of these composites is using of amorphous carbon particles as reinforcement, which was not hiherto employed. The applied reinforcing particles possess numerous interesting properties, like tribological, thermal and mechanical ones. The particles have been introduced into liquid metal through mechanical mixing. Ealier, they were coated with layers protecting against thermal destruction, enabling homogeneous distribution in matrix, increasing wettability and improving particle-matrix bonding. Influence of coating on the composite's structure and properties was assessed on the basis of mechanical and tribological characteristics. Strength studies shown that addition of the amorphous carbon particles decreases both tensile and impact strength but improves tribological features - decreases coefficient of friction and wear resistance.