SiC Reinforced Al Matrix Composites Research Articles

Reinforcing Al matrix composites by novel intermetallic/SiC interface and transition structure

Interfacial bonding has attracted extensive attention because it essentially affects the performance of SiC reinforced Al matrix composites. To investigate the impact of Ni and Cu inherent in the Al matrix on the interfacial bonding of the composite, Al–Si–Mg/oxidized SiC composite and Al–Si–Cu–Ni–Mg/unoxidized SiC composite were fabricated by semisolid stir casting. Our study demonstrated that several intermetallics can nucleate and grow on the surface of SiC in Al–Si–Cu–Ni–Mg/unoxidized SiC composite during solidification, forming the intermetallic/unoxidized SiC interface and Al-intermetallic-SiC transition structure. The bonding of the Al3CuNi/unoxidized SiC interface is stronger than the conventional Al/oxidized SiC interface. The Al3CuNi/unoxidized SiC interface is functional in impeding crack propagation and withstanding loading during deformation. Moreover, the Al-intermetallic-SiC transition structure can alleviate the agglomeration of SiC particles, improve the overall coherency and coordinate the deformation of the composite. The extraordinary interface and structure strengthen the composite to a certain extent both at room and high temperatures.

Application of grey-ANFIS system to optimize the drilling characteristics of nano SiC reinforced Al matrix composites

Application of grey-ANFIS system to optimize the drilling characteristics of nano SiC reinforced Al matrix composites

Sustainable Drilling of Nano SiC Reinforced Al Matrix Composites Using MQL and Cryogenic Cooling for Achieving the Better Surface Integrity

Metal Matrix Nano Composites (MMNCs) are progressive alternatives of formal metal materials, are presently accomplishing a growing inclination of research and engineering approaches for challenging operations such as aviation, nuclear power, and automotive for the improved mechanical properties and comparatively light in weight. Machining these MMNC leftovers, however, is a stimulating task as an effect of its mechanical heterogeneity, which primes the product of rapid wear of the tool to worsen the integrity of the surface at the point of machining. This article presents cryogenic Machining (CM), Minimum Quantity Lubrication (MQL) and Dry Machining (DM) of Nano SiC reinforced Al matrix composite and its induced surface integrity characteristics such as surface roughness, burr height and microhardness. The drilling experiments are carried out computer numeric control (CNC) machine considering a carbide drill with dia of 10 mm having a contact point of 90o, 118o, and 135o. The Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-Ray Spectroscopy (EDAX), Atomic Force Microscope (AFM), and Vickers microhardness test are used to assess the subsurface deformation and morphology. An evolutionary Non-dominated Sorting Genetic Algorithm - II (NSGA-II) is used for improving the performances such as surface roughness (SR) and burr height (BH) subjected to distinct cooling environments. The results showed that minimal SR and BH are 0.29 μm and 0.23 mm respectively under 500 rpm, 50 mm/min feed, 900point angle, and 1% wt of Nano SiC and CM shows reduced depth of plastic deformation in the subsurface of machined composites. The FESEM results show that the better surface finish are found on MMNC surface when machined under CM.

Sustainable drilling performance optimization for Nano SiC reinforced Al matrix composites

ABSTRACT Metal Matrix Composites (MMC) reinforced by nanoparticles are competent materials, appropriate for functional and structural applications. Green manufacturing is a style for mechanized that minimizes dissipate and contamination. The pollution prevention resolves in manufacturing industries to expand and execute various environmentally-friendly strategies. The primary purpose of green machining is to hold up future generations by attaining process sustainability. In the present investigation, cryogenic machining (CM) of Nanoscaled SiC reinforced Aluminum (Al) matrix composites gives experimental outcomes and also the correlation of its performance with dry machining (DM) and Minimum Quantity Lubrication (MQL). The drilling tests are organized using a vertical machining center (VMC), which is directed by computer numeric control (CNC) employing carbide drills of 10 mm dia with cutting point angles of 90, 118, and 135 degrees. Experiments have planned as per the response surface methodology (RSM) based on Box-Behnken design (BBD). Teaching–Learning-Based Optimization (TLBO) is implemented to optimize the drilling criteria such as the speed of the spindle, feed rate, weight % of nano SiC, and cutting angle. Subsequently, Scanning Electron Microscope (SEM) is utilized to inspect the subsurface of the machined specimen.

RETRACTED: The effect and mechanism of alloying elements on Al/SiC interfacial reaction in Al melt

Abstract The control of the Al SiC interfacial reaction is a critical process in the preparation of SiC-reinforced Al matrix composites. The brittle phase Al4C3 formed during the interfacial reaction can reduce the strength, elastic modulus and corrosion resistance of the composites. The impregnation method was used in this paper to observe the interfacial reaction between pure Al and SiC under different reaction conditions. It was revealed that an increase in temperature is beneficial to the decomposition of SiC, the increase of atomic diffusion rate and the nucleation of Al4C3. Furthermore, an extension of reaction time promoted the further nucleation and growth of Al4C3. Meanwhile, the experimental results showed that Cu, Si and Mg all can reduce the amount of Al4C3 formed on the interface to varying degrees and function through different influence mechanisms. These results provide significant guidance for the preparation of Al/SiC used in electronic packaging with good thermal conductivity.

Experimental Evaluation of the Lubrication Performance in MQL Grinding of Nano SiC Reinforced Al Matrix Composites

Metal matrix composites (MMCs) are materials which have been extensively used in the aerospace and automobile industries and have been categorized as hard-to-machine materials.Lubricants participate a significant role in machining, particularly in the grinding process. As a effect of the rising require for environmental safety and the growing number of health problems faced by workers, traditional lubricants are gradually being replaced. This research evaluate the performance of MQL grinding of nano SiC reinforced Al matrix composites using SAE20W40, Cashew nut shell oil and nano Tio2 filled Cashew nut shell oil as base oils. Experiments for grindability study were approved on a horizontal spindle cylindrical grinding machine using Response Surface Methodology. In this research, the influences of n grinding parameters including wheel speed, work piece speed, depth of cut and wt% nano SiC have been considered on the basis of the grinding forces and temperature to develop optimum grinding narration such as lubrication, high biological and ecological safety. The result shows that the application of nano fluid leads to the reduction of tangential forces and grinding zone temperature. Surface integrity of machined surface were studied using Scanning electron microscopy (SEM).

Roles of alloying elements in wetting of SiC by Al

Wetting of SiC by Al alloys is a key issue in the preparation of SiC-reinforced Al matrix composites. The wettability could be improved by alloying of Al, yet controversial results widely exist in the literature. We investigated the effects of four important alloying elements (Si, Cu, Ti and Mg) and their concentrations on the wettability in the Al/SiC system using a dispensed sessile-drop method. The results demonstrate that Si could weaken or even inhibit the formation of Al4C3 and substantially improve the wettability via an adsorption effect; Cu slightly deteriorates the wettability, but alleviates the formation of Al4C3 by decreasing the activity of Al; Ti strongly adsorbs at the solid−liquid interface, forming TiCx instead of Al4C3, and thus significantly improves the wettability; Mg may also favor the wettability due to its help in the disruption of the oxide film covering the Al surface via evaporation and its strong affinity for the silica film on the SiC surface; but for a clean Al/SiC system, the effect of Mg is essentially limited. In addition, the evaporation of Mg always leads to a reduction in the drop volume, which causes a decrease in the apparent contact angle, but this effect is usually neglected.

Tensile deformation of nanocrystalline Al-matrix composites: Effects of the SiC particle and graphene

Tensile deformation of SiC-reinforced Al-matrix composites are investigated via molecular dynamics simulations. To uncover the role of SiC particles in Al-matrix composites, the volume fraction, size and distribution are tailored, respectively. With increasing volume fraction of SiC particles, the elastic modulus and tensile strength of the composite are enhanced, while the ductility decreases. On the contrary, the increasing particle size at a constant volume fraction leads to an opposite trend. A sample with an inhomogeneous distribution of particles has a higher peak stress but a lower failure strain, since such an inhomogeneous distribution is more liable to block the slip of local dislocations, which may result in the localized strain distribution in the composite. By encapsulating SiC particles with graphene, the effect of graphene is also taken into account. Due to the high elastic modulus and the stronger bonding to SiC and Al, graphene enhances the elastic modulus of encapsulated SiC nanoparticles and improves the weak interface bonding between SiC and Al. Although the added graphene promotes the tensile strength of the composite, the ductility is not altered obviously due to the small size of particles.

Ameliorated mechanical and thermal properties of SiC reinforced Al matrix composites through hybridizing carbon nanotubes

By hybridizing carbon nanotubes (CNTs) into SiC reinforced Al matrix composites, a novel composite was fabricated to achieve excellent mechanical properties and low coefficient of thermal expansion simultaneously. The study demonstrated that the CNTs can help to acquire the uniform dispersion of SiC particles in the Al matrix, because of their interaction during ball milling and hot rolling processes. In addition, the results revealed that such design optimizes both the mechanical and thermal properties, due to homogeneous microstructure as well as tight and uniform interfaces induced by the addition of CNTs. Strengthening mechanism and Sideridis's model were used to discuss the effects of the CNTs on the mechanical and thermal properties. This study opens up an unexplored avenue for simultaneous improvement of the mechanical and thermal properties of metal matrix composites.

Effect of extrusion treatment on the microstructure and mechanical behavior of SiC nanowires reinforced Al matrix composites

In the present work, microstructure and mechanical performance of extruded SiCnw/Al composites have been investigated. The extrusion treatment leads to the alignment of SiC nanowires and the densification of the composites. The average length of SiC nanowires has been shortened after extrusion. High density dislocation tangles have been observed in Al matrix after extrusion. As the “non-deformable” phases, SiC nanowires inhabited the movement and deformation of surrounding Al matrix, leading to the formation of the grain boundaries. Therefore, SiC nanowires were mainly found at the boundary of Al grains in the extruded composites. Regardless of content of SiC nanowires, the yield strength, tensile strength and elongation of SiCnw/6061Al composites have been improved after extrusion treatment. Based on generalized mixture rule considering the effect of porosity, the increase of elastic modulus of SiCnw/6061Al composites is mainly due to the densification effect. The strengthening factor and efficiency of SiC nanowires are highest among all SiC reinforcements, and the strengthening behavior of SiC reinforced Al matrix composites could be well explain by the modified shear-lag model. The ratio of strengthening efficiency of SiCnw/Al composites before and after extrusion was about 0.6, indicating that orientation optimization of SiC nanowires is an effective method to improve the mechanical properties of SiCnw/Al composites.

Fabrication of SiC-Particles-Shielded Al Spheres upon Recycling Al/SiC Composites

Wettability of liquid A359 alloy on SiC particles under molten salt NaCl-KCl-NaF is found at 180 deg, meaning that SiC particles prefer the molten salt phase against the Al phase or the Al/molten salt interface. Thus, this molten salt can be used for recycling, i.e., to separate the phases in the SiC reinforced Al matrix composites. If the separation process is interrupted, Al droplets (submillimeter solidified powder) can be produced, stabilized/surrounded by a monolayer of shielding SiC particles.

Microstructures and Wear Properties of Al Matrix Composites Fabricated by Two Different Processes

SiC particulates reinforced metal matrix composites (MMCs) were fabricated by two different processes, pressureless infiltration and thermal spray. 10, 20, 30, 40 and 50 vol% SiC reinforced Al matrix composites (AMCs) were fabricated by these two processes. For these AMCs, dry sliding wear tests were performed under a normal load of 3 N, a constant sliding speed of 0.2 m/s and sliding distance of 1000 m against an AISI 52100 ball. Microstructures and wear behavior were studied by means of scanning electron microscope (SEM) and electron probe micro-analysis (EPMA).

Wear of SiC-reinforced Al-matrix composites in the temperature range 20–200°C

The influence of temperature on wear resistance was studied in a 2618 Al alloy reinforced with 15 vol% SiC particulates and the corresponding unreinforced alloy in the temperature range 20–200 °C. A transition from mild to severe wear (shown by an increase of two orders of magnitude in the wear rates) was observed in both materials beyond a critical temperature. The addition of the SiC particulates improved the wear resistance by a factor of two in the mild wear region, and the transition temperature, which was around 50 °C higher in the composite. This higher transition temperature was due to the retention of the mechanical properties in the composite at elevated temperature. Heat treatments (either natural or artificial aging) did not modify substantially the wear resistance of either the composite or the unreinforced alloy.

Particle cracking in PM processed SiC reinforced Al matrix composites: B. Wang et al (University of Alabama, USA)

Particle cracking in PM processed SiC reinforced Al matrix composites: B. Wang et al (University of Alabama, USA)