Boundaries and interfaces in ultrafine grain composites

Li, Y.; Zhang, Z.; Vogt, Rustin; Schoenung, Julie M.; Lavernia, Enrique J.

doi:10.1016/j.actamat.2011.08.005

Cited by 78 publications

(19 citation statements)

References 50 publications

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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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confidence: 99%

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

Zhang

Rufner

et al. 2015

Microsc Microanal

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“…To that effect, the interfacial structures that form between Al and B 4 C reinforcements in 5083 AA trimodal composite have been studied using high resolution transmission electron microscopy (HRTEM) [8,17,22]. Li et al [17,22] reported the presence of amorphous layers, with a typical thickness between 5 and 8 nm, separating B 4 C particles and the UFG Al phase. The authors suggested that the interfacial layers likely originated from the native surface oxide of 5083 AA during processing [17], but detailed studies were not conducted to ascertain the origin of these layers.…”

Section: Introductionmentioning

confidence: 98%

“…Inspection of the published literature shows that the mechanical behavior of trimodal composites has been studied for the past decade [13][14][15]17,18]. A widely used matrix is Al-Mg partly due to the excellent balance of strength, weldability and corrosion resistance of this family of alloys [19].…”

Section: Introductionmentioning

confidence: 99%

Metal/ceramic interface structures and segregation behavior in aluminum-based composites

Zhang

Rufner

et al. 2015

Acta Materialia

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a b s t r a c tTrimodal 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. Tailoring of microstructures with specific mechanical properties requires a detailed understanding of interfacial structures to enable strong interface bonding between ceramic reinforcement and metal matrix, and thereby allow for effective load transfer. Trimodal AA metal matrix composites typically show three characteristics that are noteworthy: nanocrystalline grains in the vicinity of the B 4 C reinforcement particles; Mg segregation at AA/B 4 C interfaces; and the presence of amorphous interfacial layers separating nanocrystalline grains from B 4 C particles. Interestingly, however, fundamental information related to the mechanisms responsible for these characteristics as well as information on local compositions and phases are absent in the current literature. In this study, we use high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy, and precession assisted electron diffraction to gain fundamental insight into the mechanisms that affect the characteristics of AA/B 4 C interfaces. Specifically, we determined interfacial structures, local composition and spatial distribution of the interfacial constituents. Near atomic resolution characterization revealed amorphous multilayers and a nanocrystalline region between Al phase and B 4 C reinforcement particles. The amorphous layers consist of nonstoichiometric Al x O y , while the nanocrystalline region is comprised of MgO nanograins. The experimental results are discussed in terms of the possible underlying mechanisms at AA/B 4 C interfaces.

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“…Reinforcement particles play an important role in determining the properties of materials. It has been reported that the presence of nanoparticles enhances strength and plasticity by interacting with dislocations, while simultaneously retarding grain growth [10,11]. In a previous work [12], we have studied Al6061 composites reinforced with Y 2 O 3 and TiC.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Aging Behavior of Al6061 Composites Reinforced with Y2O3 and TiC

Chen

Lin

2017

Metals

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Abstract:The reinforcement particles play important roles in determining microstructural development and properties of Al6061 composites. In the present work, the aging behavior of Al6061 reinforced with Y 2 O 3 and TiC particles produced via mechanical alloying are investigated. The results indicate that the peak-aged Al6061 alloy without reinforcement demonstrates the highest hardness, which corresponds to the formation of the Mg-Si precipitates. However, precipitation formation is not observed in the case of the Al6061 composites, which can be attributed to the fact that the Mg-Si clusters and GP zones are inhibited by the presence of the reinforcement particles. The solute elements segregate in the complex oxides or carbides and contribute to only a slight increase in hardness.

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Boundaries and interfaces in ultrafine grain composites

Cited by 78 publications

References 50 publications

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

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

Metal/ceramic interface structures and segregation behavior in aluminum-based composites

A Study on the Aging Behavior of Al6061 Composites Reinforced with Y2O3 and TiC

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