Magnesium Metal Matrix Composites Research Articles

Investigation of graphene-reinforced magnesium metal matrix composites processed through a solvent-based powder metallurgy route

In the present investigation, AZ31 alloy is homogeneously reinforced with 0.2, 0.3, 0.4 and 0.5 wt% of reduced graphene oxide (r-GO) nanosheets for the first time through a series of methodologies involving solvent processing, mechanical alloying, cold pressing and finally sintering under argon atmosphere at $$560^{\circ }\hbox {C}$$ . Scanning Electron Microscopy (SEM) assisted with energy-dispersive X-ray analysis revealed that this inventive fabrication route is useful to easily disperse r-GO into the matrix material and thereby attain methodical homogeneity with a uniform particle size. The attained results show that amongst the others, addition of 0.4 wt% r-GO have obviously improved the hardness up to 64.6 HV and also yielded a better inhibition efficiency of 84% on corrosion. Any further increase of r-GO content resulted for significant decrease in the wear rate up to the level of $$2.6~\hbox {mm}^{3}\hbox { Nm}^{-1}$$ .

Effects of solidification cooling rate on the corrosion resistance of a biodegradable β-TCP/Mg-Zn-Ca composite

Biodegradable beta-tricalcium phosphate (β-TCP) particle reinforced magnesium metal matrix composites (Mg-MMC) have attracted increasing interest for application as implant materials. This investigation was conducted to study the effect of cooling rate on the microstructure and corrosion behavior of a biodegradable β-TCP/Mg-Zn-Ca composite. The composite was fabricated under a series of cooling rates using a wedge-shaped casting mold. The microstructure of the composite was examined by optical and scanning electron microscopy, and the corrosion behavior was investigated using an electrochemical workstation and immersion tests in a simulated body fluid (SBF). Faster cooling rates were shown to refine the secondary phase and grain size, and produce a more homogenous microstructure. The refined microstructure resulted in a more uniform distribution of β-TCP particles, which is believed to be beneficial in the formation of a stable and compact corrosion product layer, leading to improved corrosion resistance for the composite.

Study on Fabrication of Magnesium based Metal Matrix Composites and its improvement in Mechanical and Tribological Properties- A Review

The present study, based on the literature review, reinforcing material, processing route, mechanical and tribological properties of Mg based metal matrix composites containing single and multiple reinforcement. Magnesium composites are new class metal matrix composites widely used in aerospace and automobile industries due to their low density, good mechanical properties, better corrosion and wear resistance, low thermal coefficient of expansion as compared to conventional metals and alloys. The performance of composites depends upon the right combination and composition of reinforcement material with the matrix material. This paper presents few of the available literature review the combination of reinforcement material with magnesium matrix metal. Magnesium metal matrix composites with reinforcement(s) and filler materials are finding increased applications because of improved mechanical and tribological properties. Addition of reinforcing materials such as Al2O3, SiC, B4C, metallic glass, etc., is one of the ways to enhance various mechanical and tribological properties of Mg based MMCs. When graphite is added composites decrease in tensile and hardness was observed whereas with graphite addition specific wear rate decreases. Waste materials may used as reinforcement such as fly ash, rice husk ash, etc. for low cost reinforcement which may results in better mechanical and wear properties.

Investigation of wear behaviour and microstructure of hot-pressed TiB2 particulate-reinforced magnesium matrix composites

ABSTRACTIn this study, magnesium and magnesium metal matrix composites (Mg-MMCs) reinforced with 10, 20 and 30 weight (wt.)% TiB2 particulates were produced by powder metallurgy using the hot pressing technique. The hardness, density, wear behaviour and microstructure of samples were investigated. Uniform distributions of TiB2 particulates were observed except with some partial agglomeration for 30 wt-% TiB2. When compared to pure Mg, the hardness increment of Mg-MMCs reinforced with 10, 20 and 30 wt-%TiB2 particulates was 10.7, 31.9 and 65.3%, respectively. As compared to pure Mg, under load of 20 N, the decrease in wear rate in 10, 20 and 30 wt-% reinforcement was 28.71, 34.98 and 42.92%, respectively. It is believed that the reason of decrease in wear rate was the presence of harder TiB2 particulates, which resisted to wear and plastic deformation. For pure Mg, oxidative wear changed to oxidative and mild abrasive wear transition from 10 to 20 N. Mg/TiB2 composites exhibited abrasive wear mechanism under load of 10 and 20 N except 30 wt-% TiB2 composite indicated oxidative and adhesive wear. However, a transition from mild abrasive wear to severe abrasive wear was observed with increasing load in composites.

Preparation of magnesium metal matrix composites by powder metallurgy process

Magnesium is the lightest metal used as the source for constructional alloys. Today Magnesium based metal matrix composites are widely used in aerospace, structural, oceanic and automobile applications for its light weight, low density(two thirds that of aluminium), good high temperature mechanical properties and good to excellent corrosion resistance. The reason of designing metal matrix composite is to put in the attractive attributes of metals and ceramics to the base metal. In this study magnesium metal matrix hybrid composite are developed by reinforcing pure magnesium with silicon carbide (SiC) and aluminium oxide by method of powder metallurgy. This method is less expensive and very efficient. The Hardness test was performed on the specimens prepared by powder metallurgy method. The results revealed that the micro hardness of composites was increased with the addition of silicon carbide and alumina particles in magnesium metal matrix composites.

Studies on Synthesis of Magnesium Based Metal Matrix Composites (MMCs)

Magnesium and Magnesium alloy matrix composites widely used in aerospace and automobile industries due to their low density, good mechanical properties, better wear resistance, low thermal coefficient of expansion as compared to conventional metals and alloys. This paper provides the majority techniques involved in fabrication magnesium metal matrix composites. Further, it shows that the successful synthesis of Mg (AZ91D)/ (0, 5, 10, 15, & 20 wt %) TiCP composites and found no surface defects by visual inspection. The presence of TiCp seen in an optical microscope and it shows the uniform distribution of TiCp within the matrix without any agglomeration.

Tribological behaviour of Magnesium Metal Matrix Composites reinforced with fly ash cenosphere

Now a day’s metal matrix composites are used in many industries such as aerospace and automobiles. The demand of magnesium metal matrix composites has increased in these industries mainly due to its high specific strength, better damping properties, excellent cast ability, and superior machinibility. The need of high performance and light weight material for some demanding application has led to the development of magnesium matrix composites and cost effective fabrication techniques. Tribology is a science and engineering that deals with the study and application of the principle of friction, lubrication and wear. This review article is mainly concentrated on the wear and frictional behaviour of magnesium metal matrix composites when they are reinforced with various kinds of reinforcements.

Effects of heat treatment on the microstructure and microplastic deformation behavior of SiC particles reinforced AZ61 magnesium metal matrix composite

In this paper, solution and ageing heat treatment processes were used to improve microplastic deformation behaviors of as-cast SiCp/AZ61 magnesium metal matrix composites (Mg MMCs) fabricated by stir casting method. Higher percentages of SiC particle reinforcements showed higher microhardness values. Ageing heat treatment process was seen significant on the 12h aged 2wt% SiCp/AZ61 Mg MMC which induced lower microhardness value. At the 12h ageing of 2wt% SiCp/AZ61 Mg MMC the formations of particle free regions and discontinuous secondary phases were observed. For a higher ageing time, the secondary phases distribution became continuous and laminar structure. The addition of 5wt% SiC particles resulted in the formation of Mg2Si phase throughout the whole heat treatment processes. The addition of SiC particles reinforcements increased the phase heterogeneity during ageing heat treatment processes. XRD patterns revealed the presence of nanocrystalline MgSiO3 phase on the 12h aged 2wt% SiCp/AZ61 Mg MMC. Using reference intensity ration (RIR) method a 51.6% of MgSiO3 phase was determined which can cause the formation of microplastic deformation behavior. And also, the maximum average crystallite size, compressive microstrain and microcrack-free phase boundaries were observed on the 12h aged 2wt% SiCp/AZ61 Mg MMC.

Performance of hybrid nano-micro reinforced mg metal matrix composites brake calliper: simulation approach

Most commercial vehicles use brake calliper made of grey cast iron (GCI) which possesses heavy weight. This contributes to the total weight of the vehicle which can lead to higher fuel consumption. Another major problem is GCI calliper tends to deflect during clamping action, known as “bending of bridge”. This will result in extended pedal travel. Magnesium metal matrix composites (Mg-MMC) has a potential application in the automotive industry since it having a lower density, higher strength and very good modulus of elasticity as compared to GCI. This paper proposed initial development of hybrid Mg-MMC brake calliper. This was achieved by analyzing the performance of hybrid nano-micro reinforced Mg-MMC and comparing with the conventional GCI brake calliper. It was performed using simulation in ANSYS, a finite element analysis (FEA) software. The results show that hybrid Mg-MMC has better performance in terms of reduction the weight of the brake calliper, reduction in total deformation/deflection and better ability to withstand equivalent elastic strain.

Particle Size and Particle Percentage Effect of AZ61/SiCp Magnesium Matrix Micro- and Nano-Composites on Their Mechanical Properties Due to Extrusion and Subsequent Annealing

Magnesium metal matrix composites (Mg MMCs) possess relatively more favorable mechanical properties than Mg alloys because they add reinforcements, such as small particles, short fibers, or continuous fibers, into the matrix. This study investigated the influence of adding different sizes and percentages of silicon carbide particles (SiCp) for manufacturing AZ61/SiCp Mg alloy composite extrusion plates on the mechanical properties of SiCp. We also examined the impact and discussed the evolution of microstructures, changes of material strength, ductility, formability, and other mechanical properties caused by a subsequent annealing treatment after plate extrusion. The results showed that the mechanical properties of plates can be improved by adding reinforcement particles. The effects of grain refinement were as follows: the smaller the size of the reinforcement particles, the greater the enhancement of mechanical properties. Among them, the AZ61/1 wt % SiCp/50 nm MMC plate had relatively excellent mechanical properties. Specifically, the ultimate tensile strength, yielding strength, ductility, hardness, and grain size of the plate were 331 MPa, 136.4 MPa, 43.1%, 62 HV, and 3.3 μm, respectively. Compared with SiCp-free Mg MMC plates, these properties of the AZ61/1 wt % SiCp/50 nm MMC plate were enhanced (or refined) by 6.4%, 3.4%, 83.4%, 2%, and 13.2%, respectively; by contrast, formability decreased by 9.1%.

Tribological behaviour predictions of r-GO reinforced Mg composite using ANN coupled Taguchi approach

This paper deals with the fabrication of reduced graphene oxide (r-GO) reinforced Magnesium Metal Matrix Composite (MMC) through a novel solvent based powder metallurgy route. Investigations over basic and functional properties of developed MMC reveals that addition of r-GO improvises the microhardness upto 64 HV but however decrement in specific wear rate is also notified. Visualization of worn out surfaces through SEM images clearly explains for the occurrence of plastic deformation and the presence of wear debris because of ploughing out action. Taguchi coupled Artificial Neural Network (ANN) technique is adopted to arrive at optimal values of the input parameters such as load, reinforcement weight percentage, sliding distance and sliding velocity and thereby achieve minimal target output value viz. specific wear rate. Influence of any of the input parameter over specific wear rate studied through ANOVA reveals that load acting on pin has a major influence with 38.85% followed by r-GO wt. % of 25.82%. ANN model developed to predict specific wear rate value based on the variation of input parameter facilitates better predictability with R-value of 98.4% when compared with the outcomes of regression model.

Influence of calcium hexaboride reinforced magnesium composite for the mechanical and tribological behviour

The effect of calcium hexaboride (CaB6) reinforced magnesium metal matrix composite (Mg-MMC) for mechanical and tribological behavior have been investigated. Fabrication of the Mg-MMC was done by the squeeze casting process using the bottom pouring stir casting furnace. Mechanical properties such as tensile strength and hardness of the composites were analyzed. The dry sliding wear behavior of the pure Mg and the composites was evaluated in the pin-on-disk tribo-meter using SAE52100 bearing steel disk at room temperature. Improvement in the mechanical property was found in CaB6 reinforced Mg-MMC as compared with pure Mg. A significant fact was that, addition of CaB6 enhanced the wear resistance of Mg-MMC, revealing the delamination wear mechanism is dominant from other wear mechanisms.

Processing, Microstructure and Mechanical Properties of Al2O3 and SiC Reinforced Magnesium Metal Matrix Hybrid Composites

Magnesium alloy (AZ31) is used as the base metal matrix. Alumina (Al2O3) with 5 wt%) and silicon carbide (SiC) with varying 0-8 wt% is used as the reinforcing ceramic materials. The compacted green samples were sintered at 450°C for 20 min. The prepared metal matrix composite hybrid (MMC) samples were subjected to characterization and mechanical studies such as optical microstructure, X-ray diffraction, Scanning electron microscopy (SEM), and hardness. Results showed that magnesium metal matrix composites (MMC) hardness increased from 64.53 to 75.16 HV, which was mainly due to the presence of reinforcements Al2O3 and SiC along with precipitates. Addition of alumina and silicon carbide on magnesium alloy, influenced the hardness of MMC.

Factors influencing creep resistance in discontinuously reinforced magnesium metal matrix composites

Factors influencing creep resistance in discontinuously reinforced magnesium metal matrix composites

Effects of reinforcement morphology on the mechanical behavior of magnesium metal matrix composites based on crystal plasticity modeling

In this work, we investigate the role of elastic inclusions in a plastically anisotropic matrix using crystal plasticity modeling and simulation. Magnesium (Mg) is taken as a model matrix material, which exhibits large plastic anisotropy that originates from slip and twinning mechanisms with dramatically different activation stresses. Using an idealized setup of a periodic unit cell comprising single crystal Mg matrix with an embedded elastic inclusion, we investigate the role of inclusion shape and alignment in the evolution of composite flow responses under compressive and tensile loads. This idealization serves as a model setup for highly textured microstructures that result from extrusion or rolling processes. Detailed analysis reveals how slip and twinning mechanisms evolve with strain and how they depend on the reinforcement morphology. Results indicate that under the loading condition that preferentially activate {101¯2} extension twinning, the inclusion morphology and alignment significantly influence the amount of flow hardening at a given strain and its evolution as a function of increasing strain. This twinning induced hardening effect exists in addition to the classical hydrostatic constraint effect induced by the presence of elastically stiff inclusions. We propose a simple empirical expression, which quantifies this coupling. On the other hand, when extension twinning is not an active deformation mechanism, the flow hardening characteristics are similar to the classical MMCs that deform by dislocation slip. We also investigate the effects of reinforcement aspect ratio and volume fraction on the composite responses. Finally, we briefly discuss how these observations on single crystal MMC models can be extended to textured polycrystalline Mg MMCs.

Review on mechanical properties of magnesium (nano)composites developed using energy efficient microwaves

Magnesium (with density, ρ = 1.74 g cc− 1) being ∼35% lighter than aluminium and ∼75% lighter than steel is an attractive and a viable candidate for the fabrication of lightweight structures. Being the designers' choice for weight critical applications, extensive research efforts are underway into the development of magnesium metal matrix composites (Mg-MMCs) through various cost effective fabrication technologies. In recent years, there has been a progressive advancement in utilising the microwave energy to consolidate powder materials, and the present study accentuates the use of energy efficient and environment friendly microwave sintering process to synthesise magnesium based composite materials. The processing advantages of the innovative and cost effective microwave assisted bidirectional rapid sintering technique followed by hot extrusion are first briefly introduced. Subsequently, the properties of various Mg-MMCs containing nanosized ceramic/metal particles, synthesised using this technique, are presented. Special emphasis has been made on the commending mechanical properties displayed by the nanoparticle reinforced Mg composites (Mg-MMNCs). Finally, an account of continuing research initiatives related to the development of novel lightweight Mg composites containing amorphous reinforcement is also highlighted.

Mechanical Behavior Enhancement of AM60/Al2O3p Magnesium Metal–Matrix Nanocomposites by ECAE

The effect of equal channel angular extrusion (ECAE) on the mechanical behavior of AM60/Al2O3p magnesium metal–matrix nanocomposites was investigated. ECAE is a useful technique to produce bulk nanostructured materials through severe plastic deformation. The present magnesium metal–matrix composites (Mg MMCs) with 1 wt% nanosized Al2O3 particles for ECAE were fabricated using stir-casting method. The significantly enhanced mechanical behavior of AM60/Al2O3p magnesium metal–matrix nanocomposites at room temperature, for instance, yield strength (YS), ultimate tensile strength (UTS), and ductility, can be obtained after ECAE process. The AM60/Al2O3p MMC after 4 passes of ECAE exhibited greater YS, UTS, and ductility (+135%, +107%, and +245% increase, respectively) than those of as-cast AM60. Experimental results show that the AM60/1wt %Al2O3p MMC after 4 passes of ECAE exhibits the superior mechanical behavior.

Analyses of reinforcement phases during plasma electrolytic oxidation on magnesium matrix composites

A plasma electrolytic oxidation (PEO) process on SiCP/AZ31 and Al2O3–SiO2(sf)/AZ91 magnesium metal matrix composites (MMCs) in phosphate electrolyte was carried out to reveal the evolution of SiCP and Al2O3–SiO2(sf) reinforcement phases in relation to coating growth. Optical emission spectroscopy (OES) was used to identify the elements presented in the plasma discharge process and evaluate the plasma electron temperature. XRD, SEM, EDS and ICP-AES were employed to characterize the microstructure, composition and phase constituents of the PEO coatings and the dissolved quantity of MMC in the electrolyte. The results show that the elements from the reinforcement phases can be found in the OES spectrum, which indicates that the reinforcement phases are involved in the plasma discharge, and the average electron temperature is about 5000K–7000K during the plasma discharge. The microstructure and composition suggest that MgSiO3, Mg2SiO4 and MgAl2O4 oxide layers are formed at the reinforcement/coating interface due to the local high temperature of the plasma discharge. It is believed that most of the reinforcement phases are molten firstly and then react with oxygen and magnesium oxide to form other oxides. However a few reinforcement phases still remain in the coating close to the MMC/coating interface.

Cutting Force Prediction on Micromilling Magnesium Metal Matrix Composites With Nanoreinforcements

Due to its light weight, high creep, and wear resistance, magnesium metal matrix composites (Mg-MMCs) with nanosized reinforcements are promising for various industrial applications, especially those with high volume fractions of reinforcements. The machinability of Mg-MMCs and related cutting process modeling are important to study. In this paper, an analytical cutting force model is developed to predict cutting forces of Mg-MMC reinforced with SiC nanoparticles in micromilling process. This model is different from previous ones by encompassing the behaviors of nanoparticle reinforcements in three cutting scenarios, i.e., shearing, ploughing, and elastic recovery. By using the enhanced yield strength in the cutting force model, three major strengthening factors are incorporated, including load-bearing effect, enhanced dislocation density strengthening effect, and Orowan strengthening effect. In this way, material properties, such as the particle size and volume fraction as significant factors affecting the cutting forces, are explicitly considered. To validate the model, experiments based on various cutting conditions using two types of end mills (diameters as 100 μm and 1 mm) were conducted on pure Mg, Mg-MMCs with volume fractions of 5 vol. %, 10 vol. %, and 15 vol. %. The experimental results show a good agreement with the predicted cutting force value.

Experimental investigation on the machinability of SiC nano-particles reinforced magnesium nanocomposites during micro-milling processes

This paper experimentally investigates the machinability of magnesium metal matrix composites (Mg-MMCs) with high volume fractions of SiC nano-particles using micro-milling process. The nanocomposites containing 5 vol.%, 10 vol.% and 15 vol.% reinforcements of SiC nano-particles were studied and compared with pure magnesium. The milling was carried out at different feedrates and spindle speeds chosen according to design of experiment (DOE) method. Cutting forces, surface morphology and surface roughness were measured to understand the machinability of the four different materials. Based on response surface methodology (RSM) design, experimental models and related contour plots were developed to build a connection between material properties and cutting parameters. Those models can be used to predict the cutting force, the surface roughness, and then optimise the machining conditions with the required cutting forces and surface roughness.