Aluminum Based Hybrid Metal Matrix Research Articles

Investigation of Mechanical and Tribological Behaviors of Aluminum Based Hybrid Metal Matrix Composite and Multi-Objective Optimization.

Aluminum metal matrix composites are potential materials for aerospace and automobile industrial applications due to their enhanced mechanical and tribological properties. Aluminum reinforced with silicon carbide particles has been developed with enhanced mechanical and tribological behavior, but it lacks wettability between matrix and reinforcement causing weak bonding, which reduces the degree of enhancement. The objectives of this study were to fabricate aluminum-based metal matrix composites with enhanced wettability at varying stirring speeds (350, 450, 550 rpm), stirring time (5, 10, 15 min), weight percentage of SiC (0, 5, 10 wt.%), and weight percentage of MoS2 (0, 2, 4 wt.%). Nine samples were fabricated using stir casting based on Taguchi L9 orthogonal array. Hardness, tensile strength, and wear rate of the developed composite were investigated and analyzed as a single response characteristic using Taguchi’s signal-to-noise ratio and as a multi-response characteristic using hybrid Taguchi–grey relational analysis (HTGRA). The results revealed that the addition of SiC in the composite produced better hardness, tensile strength, and wear rate. The addition of MoS2 in the composite showed better hardness and tensile strength only up to 2 wt.% of MoS2, and in the case of wear rate, the addition of MoS2 in the composite up to 4% showed better wear resistance. Al–SiC–MoS2 hybrid composite shows better enhancement in hardness, tensile strength, and wear resistance than the Al–SiC composite.

Prediction of mechanical properties of aluminium metal matrix hybrid composites synthesized using Stir casting process by Machine learning

In recent days, aluminium based hybrid metal matrix composites (Al-HMMC) is heavily demanding in aerospace and marine industry due to its enriched mechanical properties. Al7075 and Al6061 aluminium alloy are most widely used as a base matrix in Al-HMMC and stir casting method is an efficient process to manufacture them. The mechanical properties of Al-HMMC depend on material parameters and fabrication process parameters. Effecting parameters were identified based on a thorough literature review, and they include material parameters such as different types of matrix, reinforcements, and their weight percentages and sizes, as well as fabrication process (Stir Casting) parameters such as stirring speed, stirring time, and reinforcement mixing temperature. To achieve desirable results of hybrid composite materials from stir casting method, it requires high experimental cost and time. To overcome these limitations, machine learning and artificial intelligence are emerging tools, which utilize probabilistic and statistical methods to learn from the past experience based upon the experimental data to predict more accurate outcomes. In this work an attempt has been made to develop a machine learning model that can predict mechanical properties accurately. Experimental data of mechanical properties of aluminium HMMC has been collected and then used for training and testing of different machine learning models. Decision tree regression model showed maximum accuracy of 92.029 % on dataset for prediction of Ultimate Tensile strength (UTS) of Al-HMMC. The UTS of two samples of Al-HMMC with Al7075 and Al6061 as base matrix were predicted from decision tree model and compared with actual experimental values with an error < 10%.

Tribological behaviour of aluminium based hybrid metal matrix composites (Al6061/B4C/ZrO2/SiC)

This research is aimed into the use of stir casting technique to make a variety of reinforced aluminium and non-reinforced hybrid composite materials. Aluminium Metal Matrix reinforced with different volume proportions of ZrO2 (2%, 4% and 6%) and SiC (4%, 8%, 12%) particulate by stir casting techniques. Al6061 and B4C are selected as a base material and ZrO2 and SiC utilized as a reinforced material. Actual density and theoretical density are calculated using the Archimedes principle and the rule of mixtures, respectively, and the porosity is measured in terms of theoretical and actual densities. It can be observed that the density of hybrid composites increases with the addition of reinforcement materials in aluminium matrix. The Pin-on-disc apparatus was used to conduct the wear experiment various sliding distance, sliding speed and applied loads. As results concluded that wear rate of Al6061 + 2%B4C + 6%ZrO2 + 12%SiC hybrid composites are smaller than that of unreinforced aluminium alloys. From the experimental analysis the increasing reinforcements of ZrO2 and SiC particle in aluminium metal matrix decreases the wear rate of prepared hybrid samples. Increasing the load on the abrasive disk reduces the abrasion rate on all models and decreases at a sliding speed of 4.5 m / s and then increases. However, the wear rate decreases with increasing sliding speed, while the depreciation rate increases with increasing sliding distance and load.

An Investigation of corrosion of friction welded and post-weld heat-treated AA6061/SiC/graphite hybrid composites

The aluminium-based hybrid metal matrix composites have noteworthy applications in sub-sea installations, structures of deep-sea crawlers, submarine parts, engine cylinders, drum brakes etc., as they possess high strength, corrosion resistance, chemical, and dimensional stability. In this investigation, the pitting corrosion behaviour of friction welded and post-weld heat-treated AA6061/SiC/graphite hybrid composites were analysed. The corrosion rates of AW (as welded), ST (Solution treated), STA (Solution treated and Aged), and AA (Artificially Aged) weld joints were experimentally determined. The corrosion behaviour has been discussed in light of microstructure. The experimental results revealed that the STA joints exhibited better corrosion resistance characteristics as compared to AW, AA, and ST joints. The corrosion rate was high for AW joints, followed by AA and ST joints, respectively. Taking into account the corrosion rates of AW and STA joints, the STA joints have a corrosion rate 34.6% lesser than that of AW joints. A comparison of AA and ST with STA joints reveals that the rate of corrosion for STA joints was 31.1% lesser than that of AA joints and 28.8% lesser than that of ST joints. A lower corrosion rate was observed for STA joints as compared to AA, AW, and ST joints.

Effect of 6 Wt.% Particle (B4C + SiC) Reinforcement on Mechanical Properties of AA6061 Aluminum Hybrid MMC

Aluminum based hybrid metal matrix composite with more than two particle reinforcement is very much popular for heavy duty application, and the proportion of these particle reinforcement can be controlled to achieve desired mechanical properties (strength and wear resistance). AA 6061 alloys popularly used in aircraft and automobile applications, tends to have inferior tribological property and therefore particle reinforcements are being made to strengthen the matrix. The prime objective of this investigation is to study the effect of varying wt.% of proportionate individual reinforcement (SiC and B4C) on the mechanical properties of a particular composition (6 wt.%) of AA 6061 hybrid composite. The present investigation is done to evaluate the dependance of hard particle reinforcements on the strength and elongation behaviour of hybrid composite. Hardness measurement and uniaxial loading techniques were used to characterize the mechanical properties of the as-cast hybrid composites, whereas OM, XRD and SEM analysis was done to study the distribution of reinforcement within the base (AA 6061) metal matrix phase. The improvement in mechanical properties, such as Vickers hardness, UTS, yield strength and elongation were presented and explained using various hypothesis proposed by previous studies. The role of clustering theory and effect of binary eutectic Mg2Si phase found to be key the enhanced mechanical properties of the hybrid composites. Addition of Alkaline Earth Metal (Mg) during the synthesis process have led to an increase in the elongation of hybrid composite with the increase in wt.% of reinforcement which is analogous to the effect of alkali metals (‘Na’ and ‘Li’) addition that helps in refining the Mg2Si Eutectic phase.

Wear Characteristics of Hybrid Aluminium MMCs Subjected to Extrusion Process

Aluminium alloys are extensively used due to their excellent mechanical and thermal properties, However the performance of these materials are enhanced with the addition of ceramic reinforcement phase into the aluminium matrix phase, forming a newer material having improved mechanical and tribological properties. The processing technique of these materials plays a vital role in obtaining required properties of the materials. Among the available processing techniques, liquid state processing (Stir Casting) technique is widely used because of its processing feasibility. However, the problem associated with the process is agglomeration of reinforcement particles, uneven distribution, blowholes, porosity which challenges the researchers in obtaining the required properties. To overcome these limitations, Secondary processing technique like Extrusion is used which enhances the properties of processed materials. In the present work is carried out by selecting Aluminium A356 as base material to which 10% of 23μm size Al2O3 is reinforced. Hybrid composite material is processed by adding 1%, 3% & 5% MoS2 particulates of 5μm size along with Al2O3. The sliding wear characteristics of aluminium based hybrid metal matrix composites have been studied in the present work and the sliding wear resistance of the material is found to improve with addition of MoS2 particulates.

Tribo-mechanical characterisation of self-lubricating aluminium based hybrid metal matrix composite fabricated via powder metallurgy

In this research, the tribo-mechanical behaviour of self-lubricating aluminium (Al) based hybrid metal matrix composites (MMCs) reinforced with graphite (Gr) and Al2O3 particles (Al+Gr+Al2O3) were studied aiming to obtain the superior wear and mechanical properties in a single material. Three different compositions of hybrid MMCs were fabricated by powder metallurgy technique, their wear and mechanical properties were tested and compared with pure Al and Al+Gr composite. The microstructure of the samples was examined and various mechanical properties such as microhardness, tensile and flexural strength were evaluated. The wear behaviour of the hybrid MMCs was investigated by using a pin-on-disc tribometer. The results revealed that the combined effect of Al2O3 and graphite reinforcement particles significantly improved the wear and mechanical properties of hybrid MMCs. All the mechanical properties were increased and the wear rate and coefficient of friction were decreased remarkably. Besides, the reinforcement composition of 3%Gr and 10%Al2O3 (Al+3%Gr+10%Al2O3) forms a smooth tribosurface thus increases the wear-resistant properties at the highest level than that of other compositions of the hybrid MMCs.

Tribo-Mechanical Characterization of Self-Lubricating Aluminium Based Hybrid Metal Matrix Composite Fabricated Via Powder Metallurgy

In this research, the tribo-mechanical behaviour of self-lubricating aluminium (Al) based hybrid metal matrix composites (MMCs) reinforced with graphite (Gr) and Al2O3 particles (Al+Gr+Al2O3) were studied aiming to obtain the superior wear and mechanical properties in a single material. Three different compositions of hybrid MMCs were fabricated by powder metallurgy technique, their wear and mechanical properties were tested and compared with pure monolithic Al and Al+Gr composite. The microstructure of the samples was examined and various mechanical properties such as microhardness, tensile and flexural strength were evaluated. The wear behaviour of the hybrid MMCs was investigated by using a pin-on-disc tribometer. The results revealed that the combined effect of Al2O3 and graphite reinforcement particles significantly improved the wear and mechanical properties of hybrid MMCs. All the mechanical properties were increased and the wear rate and coefficient of friction were decreased remarkably. Besides, the reinforcement composition of 3%Gr and 10%Al2O3 (Al+3%Gr+10%Al2O3) forms a smooth tribosurface thus increases the wear resistant properties at the highest level than that of other compositions of the hybrid MMCs.

Optimizing the machining variables in CNC turning of aluminum based hybrid metal matrix composites

Aluminum based hybrid metal matrix composites (HMMC) are being employed nowadays in automobile, aeronautical, sports equipment etc. In this study, three different Al6063 based hybrid metal matrix composites (HMMC) samples having reinforcement with 3%, 6% and 9% by weight respectively are fabricated using stir casting method. Reinforcements used are waste products, namely, jute ash, groundnut shell and sugarcane. Surface roughness of these fabricated composite are is tested by varying machining parameters. The design of experiment is constructed by Taguchi method using three factors and two level, with L8 orthogonal array in which surface roughness is the output response parameter. These recorded results are analysed using analysis of variance and optimization of process parameters is done using response surface methodology and genetic algorithm. The Genetic algorithm optimization is achieved within 102 generations which is quite fast. On comparing it was found that results obtained from GA closely agreed with those obtained from the Response surface methodology.

Comprehensive analysis and manufacture of recycled aluminum based hybrid metal matrix composites through the combined method; sintering and sintering + forging

Recycled AA7075 aluminum alloy and pure electrolytic copper were used as the matrix to manufacture new aluminum-copper metal matrix composites (ACMMCs). Powder metallurgy methods were used and the green compacts were finalized by sintering only and sinter + forging. Experimental and numerical investigation of recycled hybrid metal matrix composites manufactured by the two methods was performed. Al–Cu matrix combined with the reinforcements ZnO, Nb2Al and SiC. Two basic formulations were used where the contents Nb2Al and SiC was kept constant and the content of ZnO were 15 wt% and 30 wt%, respectively. The effects of these reinforcements used in the hybrid metal matrix composite structure on the mechanical and physical properties were investigated. The Nb2Al, SiC ratios used in the structure (chemical interaction in the internal structure, the effects on static-dynamic compression and wear behaviors) were kept constant, in particular the ZnO component (interactions with other components and their effects on electrical properties) were investigated. Micro-hardness analyses, surface scratch tests, quasi-static and dynamic compression tests were conducted. Also, electrical conductivity of the composites were determined. The effect of the composite's formulations and production method on the results were investigated. It was found when ZnO content was reduced the yield stress and ultimate strength values increased, but their resistance to impact loading reduced. Also, sinter + forged samples exhibited higher yield stress and ultimate strength than the just sintered samples. The damage and microstructural analyses were performed by Scanning Electron Microscope (SEM). Moreover, a non-linear numerical model was utilized to simulate quasi-static compression and dynamic compression (low velocity impact) behaviors of the composites for both formulations and manufacturing methods. Finite element simulations were performed using the ABAQUS™/Explicit dynamic finite element software. It was determined that there was a satisfactory agreement between experimental and finite element model results.

Investigating the EDM parameter effects on aluminium based metal matrix composite for high MRR

Aluminum based hybrid metal matrix composite have found extensive applications in field of automobiles. This paper investigates the significant effect of machining parameters like pulse-on time (T-on), pulse-off time (T-off), voltage (V) and current (I) on material removal rate (MRR). In this study the aluminum metal matrix composite with SiCp and Grp was casted. Hybrid Aluminum metal matrix composite was machined using one tool materials (Copper) of ɸ12 mm for experiments. The design matrix and mathematical models were developed by RSM (response surface methodology) using the Design expert 9.0.6 software. The experimental results show the impact of change in parametric values on material removal rate for hybrid metal matrix composite. To check the signification of model the ANOVA (Analysis of variance) technique was used. The SEM (Scanning electron microscope) was done to study the surface characteristics of the machined samples.

Studies on mechanical properties of aluminum based hybrid metal matrix composites

Aluminum alloy provides the best alternative to steel with improved performance over the more common metals and alloys frequently used in automotive industries and aerospace segment. Hybrid Aluminum Alloys Metal Matrix Composites (HMMCs) are gaining specific attentions in automotive and aerospace applications based on its low density, high strength and its good structural rigidity. In this research work, an investigation is made to fabricate and compare the mechanical and metallurgical properties of Al 6063-Silicon Carbide with Al 6063-Silicon Carbide/Graphite hybrid metal matrix composite materials. The composites were manufactured by means of stir casting techniques in which quantity of reinforcement is in the range from 5% to 15% in steps of 5 wt.% per sample. The manufactured composites are characterized by mechanical properties, density and microstructural studies and evaluated as per ASTM standards. The optical microphotographs of the composites are uniform distribution of the hybrid particles in the composites with few clusters. The experimental densities were found to be lower than, compare to the theoretical densities in all the composites. The dispersed Silicon Carbide and Graphite in Al 6063 alloy contributed to improving the tensile strength (MPa) of the composites. From scanning electron microscope (SEM) analysis, the samples were found having uniform distribution of the hybrid reinforcement particles (SiC.and Graphite) in the matrix without any tunnel and voids effects.

Automotive industry application of aluminium-based hybrid metal matrix composite

Monolithic materials cannot fulfil the demands for the advanced industrial requirements. Therefore, composite materials which possess the combined properties of different constituents are developed. In this experimental work, Al 6061 was used as matrix and Al2O3, SiC and E glass short fibres were used as the reinforcement material. The composite specimen is fabricated through stir casting by varying the weight percentage of reinforcements and matrix materials. The investigation concluded that the load and sliding speed are expanded to improve the wear rate, and developing the sliding distance the wear rate is decreased. The different compositions of the materials are tested by using Pin on Disc apparatus to find the wear rate. From the experimental results the least wear rate is obtained in the composition (C4) of 70% wt of Al 6061, 15% wt of Al2O3, 9% wt of SiC and 6% wt of E glass short fibre.

Evaluation of recast layer and parametric optimization of EDM process on aluminium based HMMCs using grey relational analysis

Metal Matrix Composites (MMCs) have a distinct property such as superior strength, higher elastic modules, augmented wear resistance, decreased weight, and high thermal conductivity as compared to the unreinforced alloy. Due to these superior properties MMCs are difficult for machining in conventional process. Hence, an advanced machining process namely Electrical discharge machining (EDM) process was utilized. In this existent work, an optimization technique called grey relational analysis is employed by optimizing the input process parameters to expose the optimal condition for enhancing the machinability and surface quality of aluminium based hybrid metal matrix composites (HMMCs) during Electrical Discharge Machining (EDM) process. The HMMCs is machined by EDM technique by scrutinizing the input parameters such as peak current (A), pulse on time (μs) and gap voltage (v) under L27 orthogonal array. A response table was exposed to indicate the optimum conditions of the individual parameter. The ANOVA results designates that peak current is the most contributing parameter for all the samples. Finally, a verification test is conducted to authorize the optimal conditions which were derived from the response table. Further the surface effects of the machined surface such as recast layer and machined surface at the circumferential area are analysed. The recast layer is developed on the machined surface at high peak current and pulse on time. At high pulse on time, extreme heat energy was generated which increases the irregular surface on the circumferential area.

Role of TiC and h-BN particles on morphological characterization and surface effects of Al 4032 hybrid composites using EDM process

Aluminum based hybrid metal matrix composites (HMMCs) are utilized in myriad of applications owing to their attractive properties such as low weight to high strength ratio, enriched mechanical and thermal properties over other conventional materials. In this work, the consequence of TiC and h-BN particles on morphological characterization and surface effects of aluminium based HMMCs during electrical discharge machining (EDM) process is discussed. The HMMCs are fabricated by varying the wt. % of TiC and then EDM is done by examining the input parameters such as peak current (A), pulse on time (μs) and gap voltage (v) under L27 orthogonal array method. The performance and surface effects of the machined surface are evaluated after completing the EDM process. The MRR appears to surge with the rise in the peak current and decays with increasing the wt. % of TiC particles. Although by amplifying the wt. % of TiC particles, the size of the craters and the voids is augmented on the machined surface. Furthermore, as the peak current upsurges, the microhardness of the machined samples are augmented.

Dry sliding wear of heat treated hybrid metal matrix composites

In recent years, there has been an ever-increasing demand for enhancing mechanical properties of Aluminum Matrix Composites (AMCs), which are finding wide applications in the field of aerospace, automobile, defence etc,. Among all available aluminium alloys, Al6061 is extensively used owing to its excellent wear resistance and ease of processing. Newer techniques of improving the hardness and wear resistance of Al6061 by dispersing an appropriate mixture of hard ceramic powder and whiskers in the aluminium alloy are gaining popularity. The conventional aluminium based composites possess only one type of reinforcements. Addition of hard reinforcements such as silicon carbide, alumina, titanium carbide, improves hardness, strength and wear resistance of the composites. However, these composites possessing hard reinforcement do posses several problems during their machining operation. AMCs reinforced with particles of Gr have been reported to be possessing better wear characteristics owing to the reduced wear because of formation of a thin layer of Gr particles, which prevents metal to metal contact of the sliding surfaces. Further, heat treatment has a profound influence on mechanical properties of heat treatable aluminium alloys and its composites. For a solutionising temperature of 5500C, solutionising duration of 1hr, ageing temperature of 1750C, quenching media and ageing duration significantly alters mechanical properties of both aluminium alloy and its composites. In the light of the above, the present paper aims at developing aluminium based hybrid metal matrix composites containing both silicon carbide and graphite and characterize their mechanical properties by subjecting it to heat treatment. Results indicate that increase of graphite content increases wear resistance of hybrid composites reinforced with constant SiC reinforcement. Further heat treatment has a profound influence on the wear resistance of the matrix alloy as well as its hybrid composites. For all the heat treatment processes studied ice quenching with ageing duration of 6hrs resulted in improved wear resistance of both the unreinforced matrix alloy and its hybrid composites.