Forged HITEMAL: Al-based MMCs strengthened with nanometric thick Al 2 O 3 skeleton

Balog, Martin; Krížik, Peter; Nosko, Martin; Hájovská, Z.; Riglos, María Victoria Castro; Rajner, Walter; Liu, De‐Shin; Šimančík, František

doi:10.1016/j.msea.2014.06.070

Cited by 51 publications

(49 citation statements)

References 28 publications

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“…7.6f). The original oxygen-rich surfaces of the starting particles were not noticeable although they were observed in the samples consolidated at lower temperatures as shown in some previous works [3][4][5]. Therefore, the observed NPs are expected to be oxide compounds originating from the amorphous oxide layer NPs and g and h EDS spectra of the Al matrix and the NPs, respectively, in the sample consolidated from the as-received micro Al powder [38] [ [6][7][8][9][10][11][12][13] that covers the Al particles.…”

Section: Microstructural Characterizationsupporting

confidence: 68%

Consolidation of Micro- and Nano-Sized Al Powder

Casati

2015

SpringerBriefs in Applied Sciences and Technology

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In this final set of experiments, Al NPs were employed in the as-received and ball-milled condition to produce in situ reinforced MMnCs. The NPs possess higher surface than the micro-sized counterpart. This means that they may lead to the production of nanocomposites reinforced with a much higher content of in situ reinforcement and, as a limiting and desired condition, highly reinforced composites could be produced even without relying on ex situ addition of oxide NPs. For comparison, Al micro-sized powder was consolidated in the as-received condition and after ball milling as well. Furthermore, a mix of the two above-mentioned powders was also employed to complete the frame of experimental conditions. A ball-to-powder weight ratio r = 10:1 was adopted for grinding the metal powder for 16 h using 1.5 % of stearic acid as PCA. Powder consolidation was performed by BP-ECAP. It was expected that the higher content of non-metallic compound made the consolidation of powder rather difficult. It was also known that in SPD processes, more ductile and bigger particles ease the consolidation process [3] since the driving force is the severe plastic deformation of metal powder particles. On the contrary, nano-sized particles cannot accommodate high shear strains and are inclined to slip on each other instead of being deformed. Since the back-pressure (BP) revealed to be able to more efficiently consolidate powders by ECAP, it was applied for producing the nanocomposite billets. After preliminary attempts at different temperatures, 600°C was selected as a suitable temperature for producing the following full dense bulk samples: (1) As-received Al micro-powders consolidated by BP-ECAP, (2) As-received Al nano-powders consolidated by BP-ECAP, (3) Ball-milled Al micro-powders consolidated by BP-ECAP, (4) Ball-milled Al nano-powders consolidated by BP-ECAP, (5) Ball-milled Al micro-(50 wt%) and nano-powders (50 wt%) consolidated by BP-ECAP.

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Section: Microstructural Characterizationsupporting

confidence: 68%

Consolidation of Micro- and Nano-Sized Al Powder

Casati

2015

SpringerBriefs in Applied Sciences and Technology

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“…The forging die was preheated to 110 °C. The die walls were lubricated with a graphite water solution [2]. As "hot forged" condition samples of 1.2 (F12) and 8.9 m(F89) were cut and machined by turning cylinders of 10 mm in diameter to obtain SPT specimens.…”

Section: Methodsmentioning

confidence: 99%

“…The HITEMAL ® [1,2] are Al-Al 2 O 3 metal matrix composite (MMC) materials fabricated through powder metallurgy (PM) consolidation of fine atomized Al powder with mean particle size of 1-10 µm. The nanoscale Al 2 O 3 forms in situ and stems from native amorphous (am)-Al 2 O 3 layers on as-atomized feedstock Al powders.…”

Section: Introductionmentioning

confidence: 99%

“…QIFed HITEMAL shows high strengths at elevated temperatures not normally associated with use of conventional Al alloys and superior structural stability after prolonged exposures up to 400 °C, which predetermines these materials for a potential use especially in application at elevated temperatures where excellent creep resistance is required. The spreading of native oxide skin coming from elementary aluminum particles play a key role in the reinforce mechanism of these composites [2]. Such nature and spreading characteristics of the amorphous and crystalline oxide reinforce nanoparticles are strongly dependent of the raw powders and the PM processes [1].…”

Section: Introductionmentioning

confidence: 99%

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Mechanical characterization of PM aluminum composites by small punch test

2018

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In this work Small Punch Test (SPT) was applied to study the mechanical behavior of ultrafine-grained AlAl 2 O 3 metal matrix composites (MMCs) fabricated in situ via powder metallurgy route (HITEMAL ® ). Such MMCs show attractive mechanical properties, enhanced creep performance and increased thermal stability at elevated temperatures, not normally associated with service of conventional Al alloys, even after prolonged high temperature exposure. MMCs fabricated from two powders of different particle size (d 50 = 8.9 and 1.2µm) were evaluated in the present work.SPT was performed at room temperature using disc-shaped specimens of 10 mm in diameter. The effect of the different disc thickness (0.4, 0.5 and 0.6 mm) on the load vs. displacement function was evaluated. The displacements monitored from top and bottom sites of the specimen varied during the course of the test. The discs deformed throughout the test by two plastic stages, typical for ductile materials. The relation between load-displacement and stress-strain tensile curves for both composites was analyzed. A drastic change of mechanical behavior between the green compact of cold pressed material and the hot forged material was detected.New methods of determination of a characteristic load P Y , which represents a transition from elastic to plastic bending regime were presented and discussed. A relationship between P Y and corresponding yield stress was studied for each composite material by a calculation of their respective correlation parameters.

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“…[1][2][3][4][5][6][7][8][9][10][11] In a drive to further enhance the properties of MMCs, recent research has focused on reducing the reinforcement particle size from the micrometric regime to submicron and nanometric length scales. [6,9] The strength and hardness of nanoparticle-reinforced composites have been extensively studied and the operative strengthening mechanisms have been thoroughly described [6,9,12,13] with the general finding that as the reinforcement particle size decreases, the strength of the composite increases.…”

Section: Introductionmentioning

confidence: 99%

Reinforcement Size Dependence of Load Bearing Capacity in Ultrafine-Grained Metal Matrix Composites

Yang

Balog

Krížik

et al. 2017

Metall Mater Trans A

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The length-scale effects on the load bearing capacity of reinforcement particles in an ultrafine-grained metal matrix composite (MMC) were studied, paying particular attention to the nanoscale effects. We observed that the nanoparticles provide the MMCs with a higher strength but a lower stiffness compared to equivalent materials reinforced with submicron particles. The reduction in stiffness is attributed to ineffective load transfer of the local stresses to the small and equiaxed nanoparticles.

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Forged HITEMAL: Al-based MMCs strengthened with nanometric thick Al 2 O 3 skeleton

Cited by 51 publications

References 28 publications

Consolidation of Micro- and Nano-Sized Al Powder

Consolidation of Micro- and Nano-Sized Al Powder

Mechanical characterization of PM aluminum composites by small punch test

Reinforcement Size Dependence of Load Bearing Capacity in Ultrafine-Grained Metal Matrix Composites

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