Microstructural features influencing the strength of Trimodal Aluminum Metal-Matrix-Composites

Yao, Bo; Hofmeister, Clara; Patterson, Travis; Sohn, Yong Ho; Bergh, M. van den; Delahanty, Tim; Cho, Kyu

doi:10.1016/j.compositesa.2010.02.013

Cited by 60 publications

(34 citation statements)

References 26 publications

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“…Luton et al [19] suggested that O and N were coadsorbed on the surface of Al during cryomilling and were then trapped as the Al matrix particles were rewelded, and eventually, Al(ON) would form during high-temperature consolidation of the powder. Al nitrides also have been recently observed, [7,24] as well as transitional phases of Al and N. [7] Besides nitrides, cryomilling contaminants such as O, N, H, C, and Fe, in addition to alloying elements from the Al 5083 alloy such as Mg, Mn, Cu and Cr, can segregate to grain boundaries and impede grain growth. Whether or not the secondary phases of concern contain N, their effect on grain size stability could be somewhat similar.…”

Section: Introductionmentioning

confidence: 96%

“…In situations where boundary migration is impeded by secondary-phase impurities (pinning particles), the Burke model suggests that the rate of grain growth is no longer proportional to the instantaneous grain size (as expressed by Beck et al [17] ), but it is proportional to the difference between the curvature of the instantaneous grain size and the curvature of the limiting grain size. [22] Although some evidence of nitrides is found inside the structure of cryomilled Al and Al alloys, researchers have also commonly referred to Al oxynitrides, [19] Al oxides, [15,16,18,[23][24][25] and Al carbides [16,24] as additional secondary-phase particles that could inhibit grain boundary mobility. During cryomilling, Al 2 O 3 is trapped within the grains as a result of the breakup of the oxide scale inherent to the as-atomized Al 5083 particles.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Nitrogen Content on Thermal Stability and Grain Growth Kinetics of Cryomilled Al Nanocomposites

Hashemi-Sadraei

Mousavi

Vogt

et al. 2011

Metall Mater Trans A

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Nanocomposite powders of Al 5083/B 4 C were produced via cryogenic milling (cryomilling) of boron carbide (B 4 C) particles in Al 5083 matrix. The effect of milling time (up to 24 hours), and consequential nitrogen content, on grain growth in the nanocrystalline Al 5083 matrix was investigated. Thermal stability was studied at temperatures as high as~0.96 T m and annealing times of up to 24 hours. Average grain sizes increased with time and temperature and tended to stabilize after longer annealing times, regardless of nitrogen content. Higher thermal stability was observed in samples with higher nitrogen content, with the average grain size remaining in the range of 30 nm, even after exposure to the most extreme annealing conditions. This behavior was attributed to the retarding effect that nitrides have on grain growth, as a result of pinning grain boundaries. Kinetic studies based on the Burke equation showed two thermally activated grain growth regimes-a low-temperature regime with an activation energy of 15 kJ/mol and a high-temperature regime with an activation energy of 58 kJ/mol.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Influence of Nitrogen Content on Thermal Stability and Grain Growth Kinetics of Cryomilled Al Nanocomposites

Hashemi-Sadraei

Mousavi

Vogt

et al. 2011

Metall Mater Trans A

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“…A critical requirement for the application of trimodal composites is the creation of a strong interfacial bond between ceramic reinforcement and metal matrix to allow for effective load transfer. Different interfacial structures, including presence of amorphous layers between B 4 C and the UFG Al phase [1][2][3], formation of nanocrystalline grains with diameters of 30-50 nm at the Al/B 4 C interface [1,2] and segregation of Mg to Al/B 4 C interfaces [3,4], have been reported in separate literatures. However information on the relationship between different interface morphologies (e.g., amorphous layers, nanocrystalline grains, etc.)…”

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confidence: 99%

Metal/ceramic Interface Structures and Segregation Behavior in Aluminum-based Composites

Zhang

Rufner

et al. 2015

Microsc Microanal

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Trimodal Al alloy (AA) matrix composites consisting of ultrafine-grained (UFG) and coarse-grained (CG) Al phases and micron-sized B 4 C ceramic reinforcement particles exhibit combinations of strength and ductility that render them useful for potential applications in the aerospace, defense and automotive industries. A critical requirement for the application of trimodal composites is the creation of a strong interfacial bond between ceramic reinforcement and metal matrix to allow for effective load transfer. Different interfacial structures, including presence of amorphous layers between B 4 C and the UFG Al phase [1][2][3], formation of nanocrystalline grains with diameters of 30-50 nm at the Al/B 4 C interface [1,2] and segregation of Mg to Al/B 4 C interfaces [3,4], have been reported in separate literatures. However information on the relationship between different interface morphologies (e.g., amorphous layers, nanocrystalline grains, etc.) and their chemical composition profiles remains absent in the literature.The composite powder was fabricated via mixing cryomilling [5] and unmilled powder together and consists of 10 wt.% B 4 C, 30 wt.% CG 5083 AA, and the balance of UFG 5083 AA. The consolidation of mixed powder was achieved via hot isostatic pressing. Electron-transparent TEM samples were prepared by focused ion beam (FIB) sectioning. TEM imaging was performed with either a JEOL 2500 or a FEI F20 UT Tecnai. Electron Energy Loss Spectroscopy (EELS) was done with either a JEOL 2100 or a F20 UT Tecnai. Elemental distribution maps were acquired using an FEI Super-X windowless EDXS detector (FEI Company, Hillsboro, OR) installed on the Titan G2 80-200 instrument. All microscopes are operated at 200 kV. Figure 1a is a bright field TEM image demonstrating a layered structure between a B 4 C particle and the CG Al phase. Figure 1b is a HRTEM image of the same interface that reveals a double-layered interface consisting of an amorphous layer and a Mg-rich layer. Figure 2 shows integrated EELS intensity line profiles across the Al/B 4 C interfaces as a function of relative distance. Chemical composition profiling suggests the existence of Al oxide in conjunction with B 4 C, while single or multiple layers of Mg-rich oxide are observed in between Al oxide and the alloy matrix. HRTEM and EELS experiments revealed an ultra-thin amorphous aluminum oxide layer separating a poly-crystalline MgO layer from the B 4 C dispersoids. Precession assisted electron diffraction mapping was performed for the UFG Al/B 4 C interface and revealed no preferred orientation of the grains in the UFG region with respect to the B 4 C particle. Hence, grain orientation or texturing did not associate with the segregation of Mg at these interfaces.

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“…Park et al [13] investigated the high cycle fatigue behavior of 6061 Al-Mg-Si alloy reinforced Al2O3 microspheres with the varying volume fraction ranging between 5%and 30%. They found that the fatigue strength of the powder metallurgy processed composite was higher than that of the unreinforced alloy and liquid metallurgy processed composite.…”

Section: Aluminium Oxide Reinforced Amcmentioning

confidence: 99%

Study of Aluminium Metal Matrix Composites – Review

2017

IJRTER

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Metal matrix composites have superior mechanical properties in comparison to metals over a wide range of operating conditions. This makes them an attractive option in replacing metals for various engineering applications. This paper provides a literature review, on machining of Aluminium metal matrix composites (AMMC) especially the particle reinforced Aluminium metal matrix composites. This paper is an attempt to give brief account of recent work over AMMC. By suitably selecting the machining parameters, machining of AMMC can be made economical. Keywords -Aluminium metal matrix composites, Reinforcement, Cutting speed, Feed, Depth of cut, Surface finish, Mach inability etc I. INTRODUCTION In the outlook now days, finding ways to develop new structural materials with higher strength to weight ratios is one of the biggest challenges in the transportation and aerospace industry is. Properties like high specific strength, stiffness, better wear resistance and improved elevated temperature properties compared to the conventional metals and alloys are the key reasons for the increasing attention towards Metal Matrix Composites (MMCs). Composite materials consist of two or more materials that differ in chemical and physical properties and are not soluble in one another. The primary constituent in a composite material is the matrix phase that provides load transfer and structural integrity, while the reinforcement to enhance mechanical properties. The matrix and reinforcement materials can either be organic (polymers), inorganic (ceramic or glass) or metallic (aluminium, titanium, etc.). The most common forms of reinforcement materials are fibers (long and short), or particulates. Aluminium and its alloys have attracted most attention as base metal in metal matrix composites [1] . Composite materials have superior specific properties (high strength to weight ratio) compared to metals, high stiffness and good damage resistance over a wide range of operating conditions, making them an attractive option in replacing conventional materials for many engineering applications. Important properties of composite materials are: improved strength & stiffness, excellent fatigue resistance, high heat resistant, high wear resistant, high corrosion resistant, low weight etc. By suitable arrangement of metal matrix and reinforcement addition, it is possible to obtain desired properties for a particular application.Matrix materials in Metal Matrix Composites (MMC) are aluminium, magnesium and titanium alloys. Reinforcing materials in MMC are silicon carbide, boron carbide, alumina and graphite in the form of particles, short fibers (whiskers) or long fibers. In Aluminium Metal Matrix Composites (AMMC), matrix material is aluminium and reinforcement materials are silicon carbide, aluminum oxide, boron carbide, graphite etc. in the form of fibers, whiskers & particles. This paper discusses the important aspects of machining of MMC especially the Aluminium metal matrix composites. Fibers are the important class of reinforcements...

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Microstructural features influencing the strength of Trimodal Aluminum Metal-Matrix-Composites

Cited by 60 publications

References 26 publications

Influence of Nitrogen Content on Thermal Stability and Grain Growth Kinetics of Cryomilled Al Nanocomposites

Influence of Nitrogen Content on Thermal Stability and Grain Growth Kinetics of Cryomilled Al Nanocomposites

Metal/ceramic Interface Structures and Segregation Behavior in Aluminum-based Composites

Study of Aluminium Metal Matrix Composites – Review

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