SiC Particulate Metal Matrix Composites Research Articles

Novel Algebraic Matrix Method Used to Generate Linear Equation for Surface Roughness and Material Removal Rate during Wet/Dry Turning Operation on MMCs Al6061-T6/SiC

Stir casting process is well known for reinforcement of ceramic particle in aluminium. Due to improved properties of Al6061-T6/SiC particulate metal matrix composites have attracted by industry as well as received wider attention of material expertise. The purpose of this study is to evaluate the turning process parameters through algebraic matrix which is unique approach. Also studied effects of spindle speed, feed, SiC silicon carbide-3% and 6%, depth of cut and nose radius on modifier element for instance surface roughness Ra and material removal rate MRR in both dry and wet condition. In addition to optimize the turning process parameters are on Al6061-T6/SiC 3% and 6% with a coated tungsten tool. The experimental runs are designed using the taguchi based multiple factorial design DOE and their outcomes are analyzed using Analysis of Variance ANOVA. Mathematical models are established using algebraic matrix to represent the relationship among turning process parameters as independent variables, surface roughness and material removal rate as dependent variables. For every experimental run, a same cutting insert was used to encourage accurate reporting of the surface roughness and material removal rate. The statistical variations revealed that the main effect of spindle speed, feed, SiC silicon carbide-3% and 6%, depth of cut and nose radius are influenced the surface roughness and material removal rate. Moreover, Built-up-edge BUE formation was observed at every combinations of machining parameters such as spindle speed, feed, SiC silicon carbide-3% and 6%, depth of cut and nose radius which affected the surface quality negatively. The proximity of predicted results and experimental results provide proof that the algebraic matrix – DOE method has successfully established the predictive models. It is strongly suggested SiC silicon carbide 3% and 6% are successfully reinforced in Al6061 as well as optimize turning process parameters in wet condition than dry condition. Mathematical models for surface roughness and material removal rate are found to be statistically significant in wet condition.

Surface characteristics modification of lm25 aluminum alloy – 5% sic particulate metal matrix composites by friction stir processing

Stir casting is employed for successful casting of aluminum-based metal matrix composite (MMC) plates of 12 mm thickness. Surface imperfections, porosity and reinforcement agglomeration are the main concerns in stir casting processes. Solid state friction stir processing (FSP) enhances mechanical characteristics by grain refinement and uniform distribution of reinforcement of MMC. Some of the crucial specifications of FSP include the tool traverse speed, tool rotational speed, tool shoulder diameter (D/d) ratio, pin design, pin length and axial force. In this investigation, five varying tool traverse speeds ranging between 20 mm and 60 mm per min were experimented on the stir cast plates. The wear rate, microstructure and microhardness evaluation on FSP plates revealed that wear resistance of 40 mm/min tool traverse speed FSP plate is superior and attribute to significant microhardness values. In addition, fine grains, uniform distribution and SiC particle bonding with aluminum matrix contribute to effective resistance to wear.

Tension and fatigue behavior of Al-2124A/SiC-particulate metal matrix composites

The tension and fatigue properties of SupremEX® 225XE composites (Al-2124A/25%/SiCp/3 μm) were determined for extruded samples tested in the longitudinal orientation in the T4 condition. Tension testing was conducted at 0.001/sec on as-machined cylindrical samples tested with high alignment fixtures according to ASTM E−8. The fatigue tests were conducted on polished hourglass fatigue samples with stress ratio R = 0.1 and test frequency of 20 Hz using hydraulic grips on a Model 810 MTS servo-hydraulic testing machine according to ASTM E466-15. A total of 26 samples were tested with stress levels between 448 MPa and 557 MPa. The resulting stress vs. cycles to failure (i.e. S-N) curve was compared to the unreinforced matrix alloy, other unreinforced high strength aerospace aluminum alloys, as well as other conventionally processed MMCs. The SupremEX® 225XE MMC exhibited improvements to both the low cycle fatigue (LCF) and high cycle fatigue (HCF) performance compared to these materials. The fatigue strength at 107 cycles was 448 MPa, well in excess of those for monolithic aluminum alloys as well as conventionally processed MMCs. Detailed fractography revealed the presence of a unique cone-shaped fracture feature for samples failing in HCF. Calculations based on fracture morphologies suggested catastrophic fatigue fracture occurred as the material reached its critical fracture toughness. Initial modeling of this fatigue performance used a variant of the Universal Slopes Criterion proposed in early work at Case Western Reserve University by S. M. Manson.

Corrosion behavior of extremely hard Al-Cu/Mg-SiC light metal alloy composites

In this study, hot-pressing technique was used to produce Al-5wt.% Cu-20vol.% SiC and Al-5wt.% Mg-20vol.% SiC particulate metal matrix composites. The powders were ball milled and the powder mixtures were hot pressed uniaxially under a pressure of 550 MPa at a temperature of 450 °C in vacuum atmosphere for different holding times of 30, 60 and 120 min. A common observation was that the density of Al composites decreased slightly with increasing hot press sintering time. The Al-5wt.% Cu-20vol.% SiC samples exhibited maximum density of ∼95.7% ρth (theoretical density) and Al-5wt.% Mg-20vol.% SiC composite was measured with maximum density of ∼97.8% ρth after hot pressing for 30 min. The XRD and SEM characterization confirms presence of Al, SiC and CuAl2 phases for Al-Cu-SiC. Whereas the microstructure of Al-Mg-SiC composite consists of Al0.95Mg0.05 solid solution phase along with SiC phase. Among all the compositions, a maximum hardness of 3.2 GPa was noted for the Al composites, which were hot pressed at 60 min. A comparison with the existing literature reveals the presently developed Al alloy composites exhibited superior hardness. Corrosion tests were carried out using potentiodynamic polarization and electrochemical impedance spectroscopy to study the corrosion behavior of both these hard composites in marine environment (3.5wt.% NaCl) at room temperature. The corrosion rate of the samples varied between 1.8 and 2.7 mpy (mils per year), particularly, Al-5wt.% Cu-20vol.% SiC composite showed better corrosion resistance. Further impedance spectroscopy analysis revealed that Al-Cu-SiC has relatively larger semi-circular diameter when compared to Al-Mg-SiC. These observations indicate that Al-Cu-SiC exhibits high polarization resistance than Al-Mg-SiC composite.

An investigation of cutting force and tool–work interface temperature in milling of Al–SiCp metal matrix composite

Aluminium–SiC particulate metal matrix composites have attracted much interest in recent years among practitioners and researchers in the field of aerospace, automobile, nuclear, electronic packaging and other industries due to their low coefficient of thermal expansion, high strength and stiffness, hardness, wear and corrosion resistance properties. The present study focuses on aluminium A356 alloy with four different volume % of SiC particle–reinforced metal matrix composites synthesized by vacuum hot-pressing technique to achieve uniform dispersion of finer reinforcement over the matrix with higher densification. In order to study the machinability issues of the developed composites, computer numerical control end milling studies were conducted using central composite experimental design by varying cutting speed, feed and depth of cut, and the responses such as cutting forces and tool–work interface temperature were measured. The effect of machining parameters and reinforcement on the matrix during machining was analysed and optimized, which gives valuable guidelines to the manufacturing industries. The response surface models were developed and compared with experimental results. The results show that increase in volume % of SiCp reinforcement over the matrix results in higher tool–work interface temperature and needs higher cutting force during machining process.

Effect of turning parameters on surface roughness of A356/5% SiC composite produced by electromagnetic stir casting

In the present investigation, A356 alloy 5 wt% SiC composite is fabricated by electromagnetic stir casting process. An attempt has been made to investigate the effect of CNC lathe process parameters like cutting speed, depth of cut, and feed rate on surface roughness during machining of A356 alloy 5 wt% SiC particulate metal-matrix composites in dry condition. Response surface methodology (Box Behnken Method) is chosen to design the experiments. The results reveal that cutting speed increases surface roughness decreases, whereas depth of cut and feed increase surface roughness increase. Optimum values of speed (190 m/min), feed (0.14 mm/rev) and depth of cut (0.20 mm) during turning of A356 alloy 5 wt% SiC composites to minimize the surface roughness (3.15μm) have been find out. The mechanical properties of A356 alloy 5 wt% SiC were also analyzed.

Study of Cutting Force and Surface Roughness in Machining of ZA43 SiC Particulate MMC

The present paper reveals the machinability properties of Zinc - Aluminium alloy reinforced with SiC particulate metal matrix composite. The composite was prepared using liquid metallurgy technique. In this study, MMC Zn-57%Al-43% was fabricated by SiC (1% and 5%) with average particle size of 30μm. Full factorial design was used to plan the experiments (54 trials) and ANOVA method was used to analyze the results. Coated carbide tool CCMT9T304 was used in the experiment. Dry turning was employed with spindle speeds of 32, 48 and 73 m/min and feed rates of 0.2, 0.3 and 0.5 mm/rev and depths of cut of 0.25, 0.5 and 0.75 mm. It was observed from the results that cutting force was significantly affected by speed, feed and depth of cut where as surface finish was affected greatly by speed and feed. Depth of cut has less effect on surface finish.

Dry Sliding Wear Behaviour of SiC Particles Reinforced Zinc-Aluminium (ZA43) Alloy Metal Matrix Composites

The present paper reveals the wear behaviour of Zinc - Aluminium alloy reinforced with SiC particulate metal matrix composite. The composite is prepared using liquid metallurgy technique. The unlubricated pin-on disc wear test is conducted to find the wear behaviour of the ZA43 alloy based composite. The sliding wear test is conducted for different load, speed and time. The result reveals that wear rates of composite is reduced as reinforcement increases. For the same working conditions wear rate increases with increasing load and with increasing speed. The tested samples are examined by taking micro structure photos and analyzed for the type of wear. Dominating wear types observed are delamination and abrasion.

Effect of machining parameters on surface roughness and tool wear for 7075 Al alloy SiC composite

In the present study, an attempt has been made to investigate the influence of cutting speed, depth of cut, and feed rate on surface roughness during machining of 7075 Al alloy and 10 wt.% SiC particulate metal-matrix composites. The experiments were conducted on a CNC Turning Machine using tungsten carbide and polycrystalline diamond (PCD) inserts. Surface roughness of 7075Al alloy with 10 wt.% SiC composite during machining by tungsten carbide tool was found to be lower in the feed range of 0.1 to 0.3 mm/rev and depth of cut (DOC) range of 0.5 to 1.5 mm as compared to surface roughness at other process parameters considered. Above cutting speed of 220 m/min surface roughness of SiC composite during machining by PCD tool was less as compared to surface roughness at other values of cutting speed considered. Wear of tungsten carbide and PCD inserts was analyzed using a metallurgical microscope and scanning electron microscope. Flanks wear of carbide tool increased by a factor of 2.4 with the increase of cutting speed from 180 to 240 m/min at a feed of 0.1 mm/rev and a DOC of 0.5 mm. On the other hand, flanks wear of PCD insert increased by only a factor of 1.3 with the increase of cutting speed from 180 to 240 m/min at feed of 0.1 mm/rev and DOC 0.5 mm.

The drilling of Al/SiC p metal–matrix composites. Part II: workpiece surface integrity

The wide scale introduction of metal–matrix composites (MMCs) will increase simultaneously with development in technologies. Aluminum–matrix composites are widely used for their favorable specific strength/stiffness and corrosion resistance properties. As a consequence of the widening range of applications of MMCs, the machining of these materials has become a very important subject for research. MMCs are extremely difficult to machine (turning, milling, drilling, threading) due to their extreme abrasive properties. With the projected widespread application of MMCs, it is necessary to develop an appropriate technology for their efficient and cost-effective machining. This paper deals with the surface integrity of drilled Al/17%SiC particulate MMCs. Dry drilling tests, at different spindle-speed, feed rates, drills, point angles of drill and heat treatment, were conducted in order to investigate the effect of the various cutting parameters on the surface quality and the extent of the deformation of drilled surface due to drilling. For this reason, the surface roughness of the workpiece material was investigated after drilling operations. The workpiece material was drilled in four heat treatment conditions: as-received, solution treated, and solution treated and aged for 4 and 24 h. The drills used were 5 mm diameter, and 90°, 118° and 130° point angles. The experiments were performed under conditions the different speeds of 260 and 1330 rpm and the feed rates of 0.08 and 0.16 mm/rev. Drilling tests were carried out using high-speed steel (HSS), TiN coated HSS and solid carbide drills. In the experimental results, it is determined that increasing drill hardness and feed rate decrease the surface roughness of drilled surface for all heat treated conditions. In addition, the optimum surface roughness was determined when the solid carbide drill tools were used on the specimens with peakaged condition.

Microstructural characterization and tensile properties of hot pressed Al–SiC composites prepared from pure Al and Cu powders

A conventional hot pressing method was used to produce Al–Cu–SiC particulate metal matrix composites. The matrix alloy was prepared from elemental powders of Al and 5 wt.% Cu. The composite comprises 13.3 or 27.2 vol.% SiC p with an average size of 10 μm. The powder mixtures were hot pressed uniaxially under nitrogen atmosphere. It is shown that Cu aids in the formation of a liquid phase. Practically pore free structures are obtained after pressing at 600°C. Elastic modulus, tensile strength and yield strength values were improved with incorporation of the reinforcement in composites prepared by fine Al powder. The ductility, on the other hand, decreased sharply with increasing amount of strengthening phase.

Éditorial

This paper deals with the surface integrity of machined Al/20%SiC particulate metal-matrix composites (PMMC). Dry high-speed turning tests, at different cutting speeds, feed rates and depths of cut, were conducted in order to investigate the effect of the various cutting parameters on the surface quality and the extent of the sub-surface damage due to machining. The cutting tests were carried out using polycrystalline diamond tools (PCD). Scanning electron microscopic images of the machined surfaces indicate the presence of grooves and holes (due to the pull-out of SiC particles). Surface roughness measurements show that the surface roughness improves with an increase in the feed rate and the cutting speed, but slightly deteriorates with an increase in the depth of cut. This was attributed to the reduction in the flank wear of the tool with an increase in feed rate, which was discussed in detail in a companion paper published earlier (El-Gallab and Sklad, J. Mater. Proc. Tech., in press). Microscopic examination of the cross-sections of the chips indicate the localization of the matrix deformation along shear bands, where the reinforcing SiC particles align themselves. Microhardness depth profiles indicate that the sub-surface damage is confined to the top 60–100 μm. Transmission electron microscopic images of the sub-surface layers show that dislocations pile up close to the machined surface, where the matrix grains are smaller. Combining the results presented in this paper and those in the companion paper which dealt with tool wear, it is found that machining this type of composites is most economical and safe at a speed of 894 m min−1, a depth of cut of 1.5 mm and feed rates as high as 0.45 mm rev−1, when the surface roughness, Rmax, did not exceed 2.5 μm. These cutting parameters are much higher than those currently employed in the industry.

Machining of Al/SiC particulate metal matrix composites

This paper deals with the surface integrity of machined Al/20%SiC particulate metal-matrix composites (PMMC). Dry high-speed turning tests, at different cutting speeds, feed rates and depths of cut, were conducted in order to investigate the effect of the various cutting parameters on the surface quality and the extent of the sub-surface damage due to machining. The cutting tests were carried out using polycrystalline diamond tools (PCD). Scanning electron microscopic images of the machined surfaces indicate the presence of grooves and holes (due to the pull-out of SiC particles). Surface roughness measurements show that the surface roughness improves with an increase in the feed rate and the cutting speed, but slightly deteriorates with an increase in the depth of cut. This was attributed to the reduction in the flank wear of the tool with an increase in feed rate, which was discussed in detail in a companion paper published earlier (El-Gallab and Sklad, J. Mater. Proc. Tech., in press). Microscopic examination of the cross-sections of the chips indicate the localization of the matrix deformation along shear bands, where the reinforcing SiC particles align themselves. Microhardness depth profiles indicate that the sub-surface damage is confined to the top 60–100 μm. Transmission electron microscopic images of the sub-surface layers show that dislocations pile up close to the machined surface, where the matrix grains are smaller. Combining the results presented in this paper and those in the companion paper which dealt with tool wear, it is found that machining this type of composites is most economical and safe at a speed of 894 m min−1, a depth of cut of 1.5 mm and feed rates as high as 0.45 mm rev−1, when the surface roughness, Rmax, did not exceed 2.5 μm. These cutting parameters are much higher than those currently employed in the industry.

The friction and wear of Cu-based silicon carbide particulate metaal matrix composites for brake applications

The purpose of this study was to investigate the tribological characteristics of several Cu-based SiC particulate metal matrix composites (pMMCs) synthesized from copper-coated SiC particles. Pin-on-disk tests were done to compare the wear and friction properties of hemispherically lipped pMMC pins with those for grey cast iron machined from an automotive brake rotor. The sliding counterfaces in the tribotests were semi-metallic and low metallic friction materials of the type used in commercial brake pads. Against both of these counterfaces, the pMMCs exhibited lower wear rates than cast iron. It was also observed that the friction coefficients of the pMMCs against the friction material counterfaces were comparable with those for cast iron. Wear mechanisms for the CuSiC pMMC materials were studied using scanning electron and optical microscopy of the wear scars. The influence of SiC particle size and type of friction material counterface on tribological behavior of the pMMCs was also studied, as was the effect of various interfacial coatings designed to improve bonding of the matrix to the particles. A model of the wear of this pMMC material, taking into account the various material parameters, will be presented.

The flowability of particulate TiB2-containing metal matrix composite

This paper reports a study of the flow behaviour of a particulate TiB2-containing metal matrix composite (MMC) and a SiC particulate MMC containing the same matrix alloy, both in comparison with the unreinforced matrix alloy, Al-7Si-0.4Mg.Both the MMCs exhibited a similar extreme sensitivity to surface turbulence during casting, to the point at which it was not easily possible to produce good-quality castings using a conventional gravity-poured filling system. Further results obtained from fluidity measurements showed that the fluidity is not so different to conventional casting alloys, although the fluidity of the TiB2 MMC was slightly less good than the Al-SiC metal matrix composite, which in turn was poorer than the matrix alloy. A surprising result was that increasing the casting temperature did not significantly improve the fluidity of either of the MMCs.The relatively low fluidity and the high density of major defects appears to be associated with the high viscosity of the mixture and the fact that ...