Effect of Process Control Agent on the Microstructure and Mechanical Behavior of an Aluminum and B4C Metal Matrix Composite

Hofmeister, Clara; Giri, Anit K.; Brennan, Sarah; Sohn, Young-Ho; Delahanty, Tim; Cho, K.

doi:10.1007/978-3-319-48144-9_224

Cited by 4 publications

(3 citation statements)

References 7 publications

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“…The cryomilling procedure involved mixing 0.15 wt% graphite with 800 g of as‐atomized 5083 powder. The graphite was introduced as a hydrogen‐free process control agent to limit the amount of powder agglomeration due to cold welding . The blended powder was mixed with 0.64 cm (¼‐inch) diameter stainless steel milling media (at a ratio of 32:1 with the powder) and milled in liquid nitrogen for 8 hours.…”

Section: Methodsmentioning

confidence: 99%

Comparison of AC to DC current sources for field‐assisted sintering of aluminum alloy 5083 powder

Kellogg

Kornecki

Raju³

et al. 2018

J Am Ceram Soc

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The viability of resistively sintering aluminum 5083 powder with an alternating current (AC) was explored under both as-atomized and cryomilled conditions. Samples were processed under an AC field and a direct current (DC) field. Samples processed by both methods exhibited similar microstructures and densities at different die wall temperatures. For as-atomized powders, similar densities (99% of theoretical [TD]) were achieved at die wall temperatures of 564°C under DC fields and 525°C under AC fields. For cryomilled 5083, densities up to 90% of theoretical were achieved at 550°C under DC fields, while density values 99% of TD were achieved at 500°C under AC fields. Based on these findings, it has been determined that AC fields can be used as an alternative to SPS for achieving optimal density. K E Y W O R D Scryomilling, electrical conductivity, electrical properties, energy coupled to matter, field-assisted sintering technology, spark plasma sintering

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Section: Methodsmentioning

confidence: 99%

Comparison of AC to DC current sources for field‐assisted sintering of aluminum alloy 5083 powder

Kellogg

Kornecki

Raju³

et al. 2018

J Am Ceram Soc

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“…Previously, impurity concentrations of oxygen, hydrogen, carbon and nitrogen were determined through either a gas fusion (GF) or combustion-type techniques [9,[16][17][18]. The disadvantage of these techniques is that it is not possible to differentiate surface contamination from the bulk impurity concentrations and the sample is consumed during the process.…”

Section: Secondary Ion Mass Spectroscopy and The Relative Sensitivitymentioning

confidence: 99%

Quantification of nitrogen impurity and estimated Orowan strengthening through secondary ion mass spectroscopy in aluminum cryomilled for extended durations

Hofmeister

Klimov

Deleghanty³

et al. 2015

Materials Science and Engineering: A

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The strength of aluminum alloys and composites processed through powder metallurgy can be improved through the addition of nano-scale dispersoids introduced during the cryomilling process. Quantification of Orowan Strengthening from these dispersoids requires a reliable measurement of the impurity concentration. Secondary ion mass spectrometry (SIMS) was used to quantify the nitrogen impurity concentration using a 14 N ion implanted standard. An analytical approach is devised to determine the nitrogen concentration of an aluminum alloy and composite based on SIMS measurements. Results are compared to the measurements carried out by gas fusion analysis. An increase in nitrogen concentration was observed with an increase in cryomilling time up to 72 hours. The nitrogen concentration varied from 1.64 ± 0.17 at.% (0.80 ± 0.08 wt.%) to 19.12 ± 1.10 at.% (13.17 ± 0.71 wt.%) for the 8 hr and 72 hr cryomilled nanocrystalline AA5083, respectively. Assuming that all nitrogen reacts to form dispersoids, the determined nitrogen concentration was used to calculate the volume and weight fractions of dispersoids, which in turn was used to estimate the strengthening contribution via Orowan strengthening. Orowan strengthening was calculated using dispersoids of 3, 9 and 15 nm. The range of Orowan strengthening contribution was estimated in MPa to be from 7.69 ± 0.78 to 3.03 ± 0.31 for the 8 hr nanocrystalline AA5083 sample and 154.97 ± 10.29 to 61.09 ± 4.06 for the 72 hr nanocrystalline AA5083 sample.

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“…Many methods, such as pressure-less infiltration [14], casting [15,16], and powder metallurgy [17][18][19], are used for the production of B 4 C-Al composites. Among these methods, powder metallurgy is the most used technology [20][21][22], but its low efficiency and high cost severely limit its wide application. In comparison, the casting method can achieve efficient production and low cost, especially for the production of large-sized ingots.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Performance of a Three-Layered Al/7075–B4C/Al Composite Prepared by Semi Continuous Casting and Hot Rolling

Zhang

et al. 2018

Metals

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A three-layered composite material, consisting of an Al outer layer and a 7075-10 wt % B4C inner layer, was fabricated by semi-continuous casting and following a hot rolling process. The composite exhibits a clear layered structure with a good interfacial bond between layers. In the sessile drop experiment, the Al alloy melt dropped on the 7075-B4C composite at 650 °C, with the contact angle decreasing from 105° to 25° in 50 s, indicating that the infiltration and spreading both played important roles in the wetting process. In the inner layer, the reinforced B4C particles were distributed uniformly in the 7075 alloy matrix, and enhanced the average hardness of the inner layer to 163.4 HV, compared to that of the outer layer at 32.8 HV. The composite plate of 20 mm obtained the compression strength of 152 MPa. The electron probe microanalysis (EPMA) line scanning result showed that no harmful reaction or element diffusion occurred between B4C and the surrounding 7075 matrix. The B4C particles remained mechanically bonded into the matrix, and significantly reduced the bullet speed during the projectile impact test.

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Effect of Process Control Agent on the Microstructure and Mechanical Behavior of an Aluminum and B4C Metal Matrix Composite

Cited by 4 publications

References 7 publications

Comparison of AC to DC current sources for field‐assisted sintering of aluminum alloy 5083 powder

Comparison of AC to DC current sources for field‐assisted sintering of aluminum alloy 5083 powder

Quantification of nitrogen impurity and estimated Orowan strengthening through secondary ion mass spectroscopy in aluminum cryomilled for extended durations

Microstructure and Performance of a Three-Layered Al/7075–B4C/Al Composite Prepared by Semi Continuous Casting and Hot Rolling

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