Strengthening of composites due to microstructural changes in the matrix

Arsenault, R.J.; Wang, L.; Feng, C.R.

doi:10.1016/0956-7151(91)90327-w

Cited by 397 publications

(123 citation statements)

References 11 publications

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“…The influence of smaller reinforcing particles on the tensile flow stress of particle reinforced composites has been documented in several other studies [30 Á/ 34]. Smaller particles are more effective in hardening the metal matrix by dislocation punching during cool-down from processing temperatures, which accounts for the differences in yield stress [35]. At higher strains the existence of deformation gradients in the composite matrix adds yet another size-dependence to the flow stress: the smaller the reinforcements, the smaller the interparticle distances, and thus the larger the strain gradients.…”

Section: Flow Stressmentioning

confidence: 91%

Effect of reaction on the tensile behavior of infiltrated boron carbide–aluminum composites

Kouzeli

Marchi

Mortensen

2002

Materials Science and Engineering: A

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Gas pressure assisted liquid metal infiltration was employed in the fabrication of various high volume fraction B 4 C Á/Al composites. Two reaction products were observed and identified in the composites, namely AlB 2 and Al 3 BC. An increase in total volume fraction of these phases results in an increase in flow stress of the composites, concomitant to a decrease in ductility. The latter was shown to be related to an accelerated accumulation of damage, which we quantified by monitoring the stiffness of the composites as a function of strain. A simple relationship is used to quantitatively link internal damage accumulation and tensile ductility in the present composites. #

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Section: Flow Stressmentioning

confidence: 91%

Effect of reaction on the tensile behavior of infiltrated boron carbide–aluminum composites

Kouzeli

Marchi

Mortensen

2002

Materials Science and Engineering: A

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“…The resulting mechanism leads to a strengthening effect by increasing the dislocation densities, especially at the interface of fiber/matrix or near to reinforcement particles. Dislocation density was increased by the cooling rate and related to the size and the volume fraction of reinforcement particles [25].…”

Section: Tensile Propertiesmentioning

confidence: 99%

Microstructure and properties of aluminum silicon/short fibre carbon composites fabricated by semi-solid thixomixing

2015

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A novel method was developed, based on thixotropic nature of semi-solid slurry of aluminum silicon alloy, for the effective dispersion and distribution of short carbon fibers (C sf ) under intensive shear stress (τ) into the eutectic without physical or chemical damage.The C sf were distributed homogeneously into the matrix at optimum conditions: a temperature of 576-580 °C, around 48% of solid fraction, and rotation speed of mixing was at 100 rpm. The gas entrapment and porosity was a challenge in the fabrication the aluminum composite by thixomixing, and its size increased when the samples were heat treated. The extruded and heat treated composites had around 24% improvement of mechanical strength as assessed by tensile tests. The predominant deposition of silicon and its intermetallics at the interfacial region improved the wettability and adherence to achieve good mechanical properties. The formation of some intermetallics can be helpful to overcome low wettability effects and their structural evolutions were impressive. The fractography analysis illustrated the ductile fracture with some plastic deformation as the results of dimples and some fiber pull-out in the fractured surface. Ultra-micro hardness evaluation showed good interfacial bonding after heat treatment. The thixomixing process can be developed to produce various composites with different reinforcement.

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“…Na slici 2.1 prikazani su neki primeri primene čestično ojačanih kompozita sa metalnom osnovom. Povećanje čvrstoće diskontinualno ojačanih kompozita sa metalnom osnovom posledica je razlike u toplotnom širenju keramičkog ojačanja i metalne matrice [65]. U toku izrade kompozita, matrica i ojačanje zagrevaju se do procesne temperature, dovode u termomehaničku ravnotežu, a zatim ostave da se hlade.…”

Section: Diskontinualno Ojačani Kompoziti Sa Metalnom Osnovomunclassified

“…Toplotno skupljanje metalne matrice u toku hlađenja je mnogo veće nego kod ojačanja, što dovodi do geometrijske neusklađenosti. Na graničnoj površini metal/keramička čestica ovaj geometrijski disparitet stvara naprezanja, koja utiču na povećanje gustine dislokacija u matrici, u okolini čestice [65]. Pri izboru metalne osnove kompozita i ojačanja treba voditi računa o kompatibilnosti odabranih materijala, da u toku izrade kompozita ne bi došlo do odvijanja nepoželjnih hemijskih reakcija na graničnoj površini osnova/ojačanje.…”

Section: Diskontinualno Ojačani Kompoziti Sa Metalnom Osnovomunclassified

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Examination of the corrosion process impact on the microstructure and mechanical properties of Zn27Al1.5Cu0.02Mg alloy castings reinforced with silicon carbide particles

Bobić¹

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IZVODNa osnovu izvršenih istraživanja ustanovljeno je da postoji međusobna povezanost mikrostrukture, mehaničkih svojstava i korozionog ponašanja čestičnih ZA27/SiC kompozita. Livena ZA27 legura predstavlja metalnu osnovu za dobijanje kompozita. Struktura legure je tipična dendritna. Trajna transformacija dendritne u ne-dendritnu strukturu izvršena je tiksoformiranjem, dok je poluočvrsli rastop legure bio izložen dejstvu sila smicanja. Kompoziti su dobijeni kompokasting postupkom, uz infiltraciju 1, 3 i 5 mas.% SiC čestica u metalnu osnovu .. Otpornost prema koroziji matrične legure i ZA27/SiC kompozita određena je na osnovu vrednosti za brzinu korozije u rastvoru NaCl (pH=6,7). Određivanje brzine opšte korozije izvršeno je metodom gubitka mase i elektrohemijskim metodama. Otpornost matrične legure prema koroziji veća je od otpornosti kompozita. Uticaj korozije na mikrostrukturu ispitan je primenom svetlosne i skenirajuće elektronske mikroskopije. Posle izlaganja uzoraka u rastvoru NaCl, promena granice tečenja (pri ispitivanju pritiskivanjem), uzeta je kao pokazatelj uticaja korozije na mehanička svojstva matrične legure i kompozita. U matričnoj leguri procesi korozije zahvataju oblast η faze i oblast smeše faza α+η, a koroziona razaranja su površinskog karaktera. Zapaženo je da je u kompozitima sa većim sadržajem infiltriranih SiC čestica (3 i 5 mas.%) došlo do stvaranja nakupina SiC čestica, što je dovelo do obrazovanja mikroprslina i mikropora. Na ovim mestima proces korozije napreduje u dubinu materijala, što se negativno odrazilo na otpornost prema koroziji i mehanička svojstva čestičnih ZA27/SiC kompozita.Ključne reči: kompoziti sa metalnom osnovom, ZA27 legura, tiksoformiranje, kompokasting, opšta korozija, brzina korozije, gustina korozione struje, polarizaciona otpornost, mikrostruktura, granica tečenja pri ispitivanju pritiskivanjem. ABSTRACTOn the basis of examination carried out, the mutual dependence of the microstructure, mechanical properties and corrosion behaviour of particulate ZA27/SiC composites was established. As-cast ZA27 alloy was the metal matrix for producing composites. The structure of as-cast ZA27 alloy is typically dendritic. A permanent transformation of the dendritic structure into nondendritic one was achieved through thixoforming during exposure of ZA27 alloy semi-solid melt to the influence of shear forces. Composites were obtained by compocasting process, through infiltration of 1, 3 and 5 wt.% SiC particles into the metal matrix. Corrosion resistance of the metal matrix and ZA27/SiC composites was evaluated on the basis of corrosion rate in NaCl solution (pH=6.7). Mass loss method and electrochemical polarization measurements were used to determine rate of general corrosion. Matrix alloy resistance to corrosion is higher than the resistance of the composites. The influence of corrosion on the microstructure was examined using light and scanning electron microscopy. After exposure of samples in NaCl slution, compressive yield strength was taken as an indicator of corrosion i...

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Strengthening of composites due to microstructural changes in the matrix

Cited by 397 publications

References 11 publications

Effect of reaction on the tensile behavior of infiltrated boron carbide–aluminum composites

Effect of reaction on the tensile behavior of infiltrated boron carbide–aluminum composites

Microstructure and properties of aluminum silicon/short fibre carbon composites fabricated by semi-solid thixomixing

Examination of the corrosion process impact on the microstructure and mechanical properties of Zn27Al1.5Cu0.02Mg alloy castings reinforced with silicon carbide particles

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