Search results for "Metal matrix composite"
showing 10 items of 13 documents
Influence of friction stir processing conditions on the manufacturing of Al-Mg-Zn-Cu alloy/boron carbide surface composite
2018
Abstract Surface metal matrix composites were synthesized via friction stir processing (FSP) on the surface of aluminium alloy 7075 (AA 7075) sheets by incorporating B4C particles (B4CP). The influence of tool rotational speeds, powder particle sizes, and change in tool travel direction between FSP passes on particle distribution and resulting properties were studied in detail. Change in tool travel direction, decreased tool rotation speed and fine B4C particles enhanced B4CP distribution and wear properties thereof. Wear resistance of composites were doubled on account of the B4CP distribution and resultant several strengthening mechanisms.
Enhancement of mechanical properties of FSWed AA7075 lap joints through in-situ fabrication of MMC
2017
Abstract Friction Stir Processing (FSP) has been demonstrated feasible to create local Metal Matrix Composites (MMCs) in light alloys matrix. In this research, local MMCs were produced contextually to the weld using Friction Stir Welding (FSW). SiC particles were added to AA7075 lap joints by creating a proper groove on the top surface of the bottom sheet. Different welds were produced with increasing number of tool passes. The effect of the multiple passes was investigated through shear tests, macro and micro observations, average grain size and microhardness measurements. The welded joints were compared to a reference weld produced with no reinforcements. It was found that poor mixing bet…
Effect of active heating and cooling on microstructure and mechanical properties of friction stir–welded dissimilar aluminium alloy and titanium butt…
2019
A butt joint configuration of AA6061–pure Ti was welded using friction stir welding (FSW) with an assisted cooling and heating conditions, aiming to attain a flawless joint. Cooling-assisted friction stir welding (CFSW) was carried out with a different cooling medium such as CO2, compressed air and water at controlled flow rate. However, heating-assisted friction stir welding (HFSW) was performed with heating source of GTAW torch just before FSW tool at different current density. Prepared specimens were subjected to optical microscopy (OM), scanning electron microscopy (SEM) and electrodischarge spectroscopy (EDS) for microstructural characterizations. The tensile strength and microhardness…
Al-SiC Metal Matrix Composite production through Friction Stir Extrusion of aluminum chips
2017
Abstract The production of most mechanical component requires machining operation, thus usually implying the cut material to be wasted as scrap. Traditional recycling techniques are not able to efficiently recycle metal chips because of some critical aspects that characterize such kind of scraps (shape, oxide layers, contaminating residues, etc). Friction Stir Extrusion is an innovative solid state direct-recycling technique for metal machining chips. During the process, a rotating tool is plunged into a hollows matrix to compact, stir and finally, back extrudes the chips to be recycled in a full dense rod. This process results to be particularly relevant since no preliminary treatment of t…
Parameters influencing the stiffness of composites reinforced by carbon nanotubes – A numerical–analytical approach
2014
Abstract Due to their high stiffness and strength, as well as their electrical conductivity, carbon nanotubes are under intense investigation as fillers in polymer matrix composites. The nature of the carbon nanotube/polymer bonding and the curvature of the carbon nanotubes may strongly reduce the reinforcing effect of the carbon nanotubes when added to a matrix to create composites. Here the effects of carbon nanotube waviness and the interaction with the matrix on the stiffness of the composite are investigated. Using a mixed numerical–analytical model, a parametric study of the waviness and volume fraction influence of CNTs on the elastic behavior of the nanocomposite is presented. The m…
Cutting performance and indentation behaviour of diamond films on Co-cemented tungsten carbide
2000
Abstract Diamond films were grown by Hot Filament Chemical Vapour Deposition (HFCVD) on differently pretreated ISO-grade K10 cemented carbide (WC-5.8 wt.%Co) cutting inserts. Etching with diluted HNO3 and surface roughening by Murakami's reagent were used as substrate pretreatments. The adhesion of the films was evaluated by indentation tests. In order to obtain a reliable estimation of the adhesion by the slope of the crack radius–indentation load curves, a careful SEM measurement of the crack lengths was performed. Bare and diamond-coated cutting inserts were used for turning tests of Al2O3-reinforced aluminum alloy. The adhesion levels obtained from the indentation curves correlated well…
Controlling electrical percolation in multicomponent carbon nanotube dispersions
2011
Carbon nanotube reinforced polymeric composites can have favourable electrical properties, which make them useful for applications such as flat-panel displays and photovoltaic devices. However, using aqueous dispersions to fabricate composites with specific physical properties requires that the processing of the nanotube dispersion be understood and controlled while in the liquid phase. Here, using a combination of experiment and theory, we study the electrical percolation of carbon nanotubes introduced into a polymer matrix, and show that the percolation threshold can be substantially lowered by adding small quantities of a conductive polymer latex. Mixing colloidal particles of different …
Multiwalled carbon nanotube reinforced polymer composites
2008
Due to their high stiffness and strength, as well as their electrical conductivity, carbon nanotubes are under intense investigation as fillers in polymer matrix composites. The nature of the carbon nanotube/polymer bonding and the curvature of the carbon nanotubes within the polymer have arisen as particular factors in the efficacy of the carbon nanotubes to actually provide any enhanced stiffness or strength to the composite. Here the effects of carbon nanotube curvature and interface interaction with the matrix on the composite stiffness are investigated using micromechanical analysis. In particular, the effects of poor bonding and thus poor shear lag load transfer to the carbon nanotube…
Surface Reflectance: An Optical Method for Multiscale Curvature Characterization of Wear on Ceramic–Metal Composites
2020
Surface gradient characterization by light reflectance (SGCLR) is used for the first time for multiscale curvature calculations and discrimination of worn surfaces on six damaged ceramic&ndash
The performance of molybdenum toughened alumina cutting tools in turning a particulate metal matrix composite
2003
In this paper, a study of the tool wear mechanism in turning aluminium alloy reinforced with alumina using molybdenum-toughened alumina tools is presented. Alumina tools with three different amounts (15, 20 and 25 vol.%) of molybdenum were prepared and tested. The wear type was identified and its evolution with cutting time was measured. The results show that the main mechanism of tool wear is abrasion and not heat. The best overall performance was achieved, as far as flank wear is concerned, using the tool with 20 vol.% of molybdenum added. This has been explained using some of the composites intrinsic properties. SEM examination revealed that molybdenum particles are easily torn from the …