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Title: Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites.

Abstract

Abstract not provided.

Authors:
;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1264296
Report Number(s):
SAND2006-1529C
525901
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the TMS Annual Meeting held March 13-16, 2006 in San Antonio, TX.
Country of Publication:
United States
Language:
English

Citation Formats

Prasad, Somuri V., and Asthana, Rajiv. Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites.. United States: N. p., 2006. Web.
Prasad, Somuri V., & Asthana, Rajiv. Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites.. United States.
Prasad, Somuri V., and Asthana, Rajiv. Wed . "Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites.". United States. doi:. https://www.osti.gov/servlets/purl/1264296.
@article{osti_1264296,
title = {Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Friction and Wear Mechanisms in Aluminum Alloy Metal-Matrix Composites.},
author = {Prasad, Somuri V. and Asthana, Rajiv},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2006},
month = {Wed Mar 01 00:00:00 EST 2006}
}

Conference:
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  • The main aim of this study is to produce copper reinforced metal matrix composite (MMC) layers using micron sized SiC particles via friction stir processing (FSP) in order to enhance surface mechanical properties. Microstructural evaluation using optical microscopy (OM) and scanning electron microscopy (SEM) indicated that an increase in traverse speed and a decrease in rotational speed cause a reduction in the grain size of stir zone (SZ) for the specimens friction stir processed (FSPed) without SiC particles. With the aim of determining the optimum processing parameters, the effect of traverse speed as the main processing variable on microstructure andmore » microhardness of MMC layers was investigated. Higher traverse speeds resulted in poor dispersion of SiC particles and consequently reduced the microhardness values of MMC layers. It was found that upon addition of SiC particles, wear properties were improved. This behavior was further supported by SEM images of wear surfaces. Results demonstrated that the microcomposite produced by FSP exhibited enhanced wear resistance and higher average friction coefficient in comparison with pure copper. Tensile properties and fracture characteristics of the specimens FSPed with and without SiC particles and pure copper were also evaluated. According to the results, the MMC layer produced by FSP showed lower strength and elongation than pure copper while a remarkable elongation was observed for FSPed specimen without SiC particles. Research Highlights: {yields} Decrease in traverse speed leads to good dispersion of SiC particles in composites. {yields} No distinct TMAZ in side regions of SZ of FSPed specimens with SiC particles. {yields} Microhardness of FSPed specimens with SiC particles shows a remarkable increase. {yields} Reinforcement of Cu with SiC particles improves wear and friction behavior of surface. {yields} A weak bonding in tensile due to probable agglomeration for SiC containing samples.« less
  • Tool wear for threaded steel pin tools declines with decreasing rotation speed and increasing traverse or weld speeds for the friction-stir welding (FSW) of Al 359+20% SiC metal-matrix composite (MMC). Less than 10% tool wear occurs when the threaded tool erodes to a self-optimized shape resembling a pseudo-hour glass at weld traverse distances in excess of 3 m. There is only a 7% reduction in the SiC mean particle size in the weld zone for self-optimized pin tools with no threads as compared with a 25% variation for threaded tools wearing significantly at the start of welding. The weld zonemore » becomes more homogeneous for efficient welding with self-optimized tools, and there is a reduction in the weld zone grain size due to dynamic recrystallization, which facilitates the solid-state flow. Transmission electron microscopy shows little difference in the dislocation density from the base material to the weld zone, but there is a propensity of dislocation loops in the weld zone. The weld zone is observed to harden by as much as 30%, in contrast to the base material, as a consequence of the recrystallized grain size reduction and the SiC particles distributed therein.« less
  • The wear behavior of A356 aluminum alloy (Al-7 pct Si-0.3 pct Mg) matrix composites reinforced with 20 vol pct SiC particles and 3 or 10 vol pct graphite was investigated. These hybrid composites represent the merging of two philosophies in tribological material design: soft-particle lubrication by graphite and hard-particle reinforcement by carbide particles. The wear tests were performed using a block-on-ring (SAE 52100 steel) wear machine under dry sliding conditions within a load range of 1 to 441 N. The microstructural and compositional changes that took place during wear were characterized using scanning electron microscopy (SEM), Auger electron spectroscopy (AES),more » energy-dispersive X-ray spectroscopy (EDXA), and X0ray diffractometry (XRD). The wear resistance of 3 pct graphite-20 pct SiC-A356 hybrid composite was comparable to 20 pct SiC-A356 without graphite at low and medium loads. At loads below 20 N, both hybrid and 20 pct SiC-A356 composites without graphite demonstrated wear rates up to 10 times lower than the unreinforced A356 alloy due to the load-carrying capacity of SiC particles. The wear resistance of 3 pct graphite 20 pct SiC-A356 was 1 to 2 times higher than 10 pct graphite-containing hybrid composites at high loads. However, graphite addition reduced the counterface wear. The unreinforced A356 and 20 pct SiC-A356 showed a transition from mild to severe wear at 95 N and 225 N, respectively. Hybrid composites with 3 pct and 10 pct graphite did not show such a transition over the entire load range, indicating that graphite improved the seizure resistance of the composites.« less
  • The friction and wear behavior of the gold-base (ASTM B541) and palladium-base (ASTM B540) alloy couple has been investigated in three environments as a function of the metallurgical state of the alloys. One environment was laboratory air with 35 to 45% relative humidity; careful controls were imposed to prevent spurious contamination by organic materials. A second environment was high-purity air, contained in a glove box and controlled to less than 1 ppM hydrocarbon and 1 ppM water contamination. The third environment was ultra-high-purity helium, again controlled in a glove box to impurity levels of less than 1 ppM oxygen, watermore » and organic contaminants. The microstructures and hardnesses of the alloys were varied by age-hardening heat treatments and/or cold rolling. Hardnesses for the gold-base alloy varied from HK=332 to HK=354, with the hardnesses of the palladium base alloy varying from HK=337 to HK=353. Friction and wear measurements were made with a pin-on-disc configuration with the palladium alloy serving as the pin and the gold alloy acting as the plate. The poorest friction performance was found in the helium environment where both magnitudes and break-in characteristics varied extensively. The friction coefficient varied from 0.25 to 2.0; the variation for a specific pin-plate combination masked pin-plate material differences, except for cold-rolled plates which had the worst performance. The poor performance in helium is compared with improved performance in the oxygen containing atmospheres where friction coefficients ranged from 0.1 to 0.25. In oxygen containing environments, the break-in was minimal and reproducible.« less
  • Aluminum metal-matrix composites (Al-MMC) are rapidly becoming materials of choice for many aerospace, automotive, recreational sports, and microelectronic applications. The attractive features of these materials include high specific strength and stiffness, a low coefficient of thermal expansion and enhanced wear characteristics relative to monolithic aluminum alloys. The effective engineering application of Al-MMC will commonly require their joining beth to themselves, to dissimilar Al-MMC, and to monolithic aluminum alloys. In the present work, dissimilar-alloy inertia-friction welds were produced between a 6061-T6 Al-MMC tube reinforced with l0 v/o Al{sub x}O{sub 3} particles (W6A.l0A-T6) and a modified A356 case MMC bar reinforced withmore » 20 v/o SiC particles (F3S.20S), or a monolithic 6061-T6511 aluminum alloy bar. In Phase I, a fractional-factorial test matrix was statistically designed and performed to evaluate the effects of flywheel speed and axial pressure on the weld integrity, microstructure, hardness, tensile and torsion strengths and fracture behavior. In Phase 2, the effects of pre-weld machining of the solid bar on weld alignment and mechanical properties were evaluated. inertia-friction welding was shown to be effective for the joining of alumina particulate-reinforced composites to monolithic aluminum and to SiC-particulate reinforced aluminum. High-integrity joints exhibiting a defect-free joint interface with varying degrees of base alloy intermixing were produced at optimum parameter settings. Tensile and torsional strength joint efficiencies for the alumina-particulate MMC to monolithic aluminum alloy welds exceeded 80% and 75%, respectively, with tensile strength maximized with high axial pressure and flywheel speed, and torsional strength maximized at both medium and high levels of flywheel speed and axial pressure.« less