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1.
ACS Omega ; 8(30): 26828-26836, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37546647

RESUMO

In the current study, a two-stage stir cast process was used to produce Al6082 reinforced with sized graphite particulates, and the material's mechanical and tribological properties were analyzed. The graphite content in the Al6082 alloy was increased from 2 to 6% in steps of 2 wt %. The impact of graphite addition to Al6082 was evaluated using microstructural micrographs, hardness test, tensile test, and wear test outcomes. The matrix alloy's microstructure and particle distribution were analyzed using scanning electron microscopy and energy-dispersive spectroscopy. The microstructure of Al6082 shows that the reinforcement particles are evenly distributed throughout the matrix. Although the hardness of metal-matrix composites was slightly reduced when graphite was added at concentrations of up to 6 wt %, the material's tensile strength and wear resistance were significantly improved. Micrographs taken by a microscope were used to examine the fractured surfaces of tensile test specimens. Wear experiments were performed using a conventional pin-on-disc tribometer to examine the tribological properties of both unreinforced matrix and graphite composites. With the addition of 2, 4, and 6 wt % of graphite particles, the composites' wear resistance was significantly improved. Wear of alloys and their composites was analyzed to determine how load and sliding speed impacted wear loss.

2.
ACS Omega ; 8(29): 26332-26339, 2023 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-37521657

RESUMO

The present study aims at producing transient liquid phase (TLP) bonded Al2219 joints with pure Cu (copper) as an interlayer. The TLP bonding is carried out at the bonding temperatures in the range of 480 to 520 °C while keeping the bonding pressure (2 MPa) and time (30 min.) constant. Reaction layers are formed at the Al-Cu interface with a significant increase in diffusion depth with the increase in the bonding temperature. The microstructural investigations are carried out using scanning electron microscopy and energy-dispersive spectroscopy. X-ray diffraction study confirms the formation of CuAl2, CuAl, and Cu9Al4 intermetallic compounds across the interface of the bonded specimens. An increase in microhardness is observed across the bonding zone with the increase in the bonding temperature, and a maximum hardness value of 723 Hv is obtained on the diffusion zone of the specimen bonded at 520 °C. Furthermore, the fractography study of the bonded specimens is carried out, and a maximum shear strength of 18.75 MPa is observed on the joints produced at 520 °C.

3.
ACS Omega ; 8(26): 23763-23771, 2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37426234

RESUMO

Micron-sized B4C addition to the Al2011 alloy was investigated for its impact on mechanical and wear performance. The stir-casting method was used to manufacture the Al2011 alloy metal matrix composites reinforced with varying percentages of B4C particulates (2, 4, and 6). The microstructural, mechanical, and wear properties of the synthesized composites were tested. scanning electronic microscope (SEM) microscopy and XRD patterns were used to characterize the microstructure of the samples that were obtained. The XRD patterns confirmed the presence of B4C particles. The addition of B4C reinforcement increased the metal composite's hardness, tensile strength, and compressive strength. Incorporating the reinforcement resulted in a decrease in elongation for the Al2011 alloy composite. The wear behavior of the prepared samples was examined under various load and speed conditions. In terms of wear resistance, the microcomposites were far superior. SEM observations of the Al2011-B4C composites revealed numerous fracture and wear mechanisms.

4.
ACS Omega ; 8(26): 23528-23544, 2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37426284

RESUMO

Hybrid composite materials are a form of material that incorporates more than one type of reinforcement into a matrix to attain enhanced qualities. This usually includes the use of nanoparticle fillers in classic advanced composites with fiber reinforcements such as carbon or glass. In the current investigation, the impact of carbon nanopowder filler on the wear and thermal performance of the chopped strand mat E-glass fiber-reinforced epoxy composite (GFREC) were analyzed. Multiwall carbon nanotube (MWCNT) fillers were used; they react with the resin system to contribute a significant improvement of properties in the polymer cross-linking web. The experiments were carried out employing the central composite method of design of experiment (DOE). A polynomial mathematical model was created using response surface methodology (RSM). To forecast the wear rate of composites, four machine learning (ML) regression models were built. The study's findings indicate that the addition of carbon nanopowder has a substantial impact on the wear behavior of composites. This is mostly owing to the homogeneity created by the carbon nanofillers in uniformly dispersing the reinforcements in the matrix phase. Results revealed that a load of 1.005 kg, a sliding velocity of 1.499 m/s, a sliding distance of 150 m, and 15 wt % of filler were found to be the optimal parameters for the efficient reduction of specific wear rate. Composites with 10 and 20% carbon contents exhibit lower thermal expansion coefficients than plain composites. These composites' coefficients of thermal expansion fell by 45 and 9%, respectively. If the carbon proportion increases beyond 20%, so will the thermal coefficient of expansion.

5.
ACS Omega ; 8(14): 13444-13455, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37065059

RESUMO

An Al2014-alumina (Al2O3) composite's characteristics are significantly influenced by the reinforcement particle size variation. Therefore, this study examines the microstructure, mechanical, fractography, and wear performance of an Al2014-Al2O3p composite made using a unique two-stage stir casting method and various alumina weight fractions (9, 12, and 15 wt %). Three categories of alumina particle size are used, i.e., fine particle size (FPS, 8 µm), intermediate particle size (IPS, 53 µm), and coarse particle size (CPS, 88 µm). The shapes of the composites were characterized using scanning electron microscopy. According to scanning electron microscopic analyses of the microstructure, the FPS dispersion was more uniform than IPS and CPS, whereas CPS causes agglomeration. Additionally, the studies show that the FPS composite outperformed CPS and IPS composites in terms of mechanical characteristics and wear performance. The fractography study shows conical and equiaxed dimple failure in the Al2014 matrix and the circular cavities.

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