Magnesium Composites Research Articles

Effect of ageing temperature on the corrosion behaviour of UHTC particulates reinforced magnesium composites fabricated through ultrasonic assisted squeeze casting process

The corrosion behaviour of AZ91D magnesium alloy reinforced with 5-wt% of various Ultra High-Temperature Ceramics (UHTC) such as TaC, HfC, TiN, TiB2, and TiC has been analysed in this current research work. AZ91D magnesium alloy and proposed composites were fabricated through ultrasonic assisted squeeze casting process and followed by T6 heat treatment at different ageing temperatures (170, 200, 230, and 260 °C). As per ASTM standards, the fabricated composites were subjected to various analyses on density, porosity, microstructure, hardness, and corrosion behaviour. The distribution of reinforcements was revealed by the optical microscope and scanning electron microscope images of composites. The presence of primary phase (α-Mg), intermetallic phase (β-Mg17Al12) and reinforcements in the composites were confirmed in the XRD analysis. Because of high densification, lower grain size, and lesser porosity level, TaC and HfC particulate reinforced composites showed higher hardness (170.3 and 160.4 HV respectively) at 230 °C compared to other composites. The salt spray corrosion test (3.5 wt% NaCl) on composites with varying exposure times (24, 48, and 72 h) revealed that, due to the formation of a dense and stable anti-corrosion protective layer with reduced β-Mg17Al12 phase, TaC and HfC composites exhibited higher corrosion resistance up to 48 h and ageing temperature of 230 °C. The scanning electron microscope image of the corroded samples showed pits and crack formation at an exposure period of 72 h.

WITHDRAWN: Mechanical and corrosion behavior of Groundnut Shell ash particle (GSAp) reinforced AZ31 magnesium composite

Magnesium based alloys are some of the widely used lightweight metals in vehicles and aerospace industries, but these materials are having low strength to weight ratio when compared to Aluminium. To enhance the strength to weight ratio of magnesium, some ceramic materials like carbides and oxides of metals or some natural residues are added as reinforcements and proved to have better augmentations in the physical properties. In the present work, AZ31 magnesium alloy is reinforced with 1%, 2%, 3% of Ground Nut Shell Ash particles (GSAp) through powder metallurgy, and properties like Micro hardness, Compressive strength is studied and the Microstructural analysis is also done. The addition of ash particles as reinforcement has not shown much variation in the strength and hardness, the addition of ash particles more than 3% leads to crack and the addition of ash particles increases the rate of corrosion.

Recent studies on particulate reinforced AZ91 magnesium composites fabricated by Stir casting – A review

Magnesium Metal Matrix Composites (Mg MMC) have been the focus of consideration by many researchers for the past few years. Many applications of Mg MMCs were evolved in less span of time in the automotive and aerospace sector to capture the benefit of high strength to weight ratio along with improved corrosion resistance. However, the performance of these materials in critical conditions is significantly influenced by several factors including the fabrication methods used for processing the composites. Most of the papers addressed all the manufacturing strategies of Mg MMC but no paper was recognized as a dedicated source for magnesium composites prepared through stir casting process. Since stir casting is the least expensive and most common process in the preparation of composites, this paper reviews particulate based Mg MMCs fabricated with stir casting technology. AZ91 series alloys are considered as the matrix material while the effect of different particle reinforcements, sizes , weight fractions on mechanical and tribological responses are elaborated in support with micro structural examinations. Technical difficulties and latest innovations happened during the last decade in making Mg MMCs as high performance material are also presented.

Effect of Surfactant Polyvinyl Pyrrolidone on the Properties of Microporous Carbon Nanospheres Reinforced Magnesium Matrix Composites.

Microporous carbon nanospheres (PCNS)-reinforced magnesium (Mg) composites were prepared using polyvinyl pyrrolidone (PVP) as surfactant and PCNS as reinforcement. The influence of PVP treatment and the effectiveness of PCNS on the mechanical properties of Mg-based composites were investigated. The results show that the PCNS can enhance the properties of the Mg matrix. Moreover, the PVP can effectively improve the dispersion of PCNS in the Mg matrix but had a negative influence on the tensile properties of composites. The MgO films with high tensile strength were produced between matrix and reinforcement after removing PVP, which effectively promotes the interface compatibility and improves the properties of the composite. The tensile yield strength and specific strength of PCNS-reinforced Mg matrix composite exhibited 177 MPa and 102.4 × 103 N∙m/kg, respectively, which were 77% and 78% higher than those of the Mg matrix.

Equal channel angular pressing and mechanical investigation of magnesium composite with aluminium oxide and silicon carbide as reinforcements

In this experimental analysis pure magnesium based aluminium oxide and silicon carbide reinforced hybrid composite was prepared by stir casting process. The mechanical and metallurgical properties of magnesium composite before and after equal channel angular processing (ECAP) were analysed. The scanned electron microscopy (SEM) investigation reveals about the uniform distribution of aluminium oxide and silicon carbide reinforcement particles in the magnesium matrix composite. The results show that the tensile strength of magnesium matrix composite was improved drastically by the effect of ECAP process. Further the hardness property was also increased by the incorporation of silicon carbide reinforcement particle. All these results depicts that the hybrid magnesium composite can be developed as the best material where homogeneous mixture, improved hardness and ultimate tensile strength are of primary importance in automotive and aerospace applications.

Mechanical and microstructural properties of graphene reinforced magnesium composite

Abstract Magnesium (AZ31) is suited for implant having good biocompatibility and elastic modulus. In this paper biocompatibility material was prepared by reinforcing hardest Graphene nano particles. This paper portraits the fabrication of Biocompatibility composite material by reinforcing Nanographene with different weight percentage (0.2 wt%, 0.4 wt%, 0.6 wt%) with magnesium alloy (AZ31), by stir casting process. The composite material was studied for its properties such as micro hardness, microstructure, tensile strength, Impact strength and density, compared with the base (AZ31) alloy .The study describe the potential application of (AZ31) Magnesium alloy with reinforced particle which suits for implant application and human bone related material. The study describe the potential application of (AZ31) Magnesium alloy with reinforced particle which suits for implant application and human bone related material.

Mechanical Properties and Corrosion Resistance of Magnesium–Hydroxyapatite Composites Fabricated by Spark Plasma Sintering

Recent studies indicate that biodegradable magnesium alloys and composites are attracting a great deal of attention in orthopedic applications. In this study, magnesium–hydroxyapatite (Mg–HAP) composites with different compositions and grain size were fabricated by a spark plasma sintering (SPS) method. Their mechanical properties and corrosion behavior in a pseudo-physiological environment were investigated by pH measurements and inductivity coupled plasma (ICP) elemental analysis after an immersion test using Hanks’ solution. The results clearly showed that the addition of HAP improved both the mechanical properties and corrosion resistance. The results also indicated that the finer grain size improved most of the properties that are needed in a material for an orthopedic implant. Furthermore, the authors reveal that there is a strong correlation between the compressive strength and the porosity. In order to achieve the same compressive strength as human bone using these fabrication conditions, it is revealed that the porosity should be lower than 1.9%.

Cryogenic Drilling of AZ31 Magnesium Syntactic Foams.

Machined surface quality and integrity affect the corrosion performance of AZ31 magnesium composites. These novel materials are preferred for temporary orthopedic and vascular implants. In this paper, the drilling performance of AZ31-magnesium reinforced with hollow alumina microsphere syntactic foam under LN2 cryogenic, dry, and Almag® Oil is presented. Cutting tests were conducted using TiAlN physical vapor deposition (PVD) coated multilayer carbide and K10 uncoated carbide twist drills. AZ31 magnesium matrices were reinforced with hollow alumina ceramic microspheres with varying volume fractions (5%, 10%, 15%) and average bubble sizes. Experimental results showed that the drilling thrust forces increased by 250% with increasing feed rate (0.05 to 0.6 mm/tooth) and 46% with the increasing volume fraction of alumina microspheres (5% to 15%). Cryogenic machining generated 45% higher thrust forces compared to dry and wet machining. The higher the volume fraction and the finer the average size of hollow microspheres, the higher were the thrust forces. Cryogenic machining (0.42 µm) produced a 75% improvement in surface roughness (Ra) values compared to wet machining (1.84 µm) with minimal subsurface machining-induced defects. Surface quality deteriorated by 129% with an increasing volume fraction of alumina microspheres (0.61 µm to 1.4 µm). Burr height reduction of 53% was achieved with cryogenic machining (60 µm) compared to dry machining (130 µm). Overall, compared to dry and wet machining methods, cryogenic drilling can be employed for the machining of AZ31 magnesium syntactic foams to achieve good surface quality and integrity.

Using low-temperature sinterless powder method to develop exceptionally high amount of zinc containing Mg–Zn–Ca alloy and Mg–Zn–Ca/SiO2 nanocomposite

Magnesium alloys and composites have gained critical importance in several industries owing to their superior specific properties. Understanding and interpreting the influence of the processing technology, alloying and reinforcement addition on the mechanical response of magnesium is vital to improve its commercial acceptability. The presence of secondary phases in a magnesium alloy system influences the behavior of the material tremendously. The incorporation of alloying elements beyond the solubility limits using high-temperature processing technologies may result in unwanted secondary phases which might be detrimental. In this study, Mg–19Zn–1Ca alloy and Mg–19Zn–1Ca+1SiO2 nanocomposite containing an exceptionally high amount of zinc (19 wt percent) were fabricated via sinterless powder metallurgy method followed by hot extrusion by judiciously controlling temperature at each stage to minimize secondary phase formation. The addition of SiO2 nanoparticles to such alloy was further investigated. Results revealed a low incidence of secondary phase formation leading to enhanced physical and mechanical properties when compared to high weight percent Zn compositions fabricated using traditional methods and many commonly used commercial Mg alloys and stainless steel. The addition of SiO2 nanoparticles enhanced thermal stability and damping response marginally while compressive yield strength, ultimate compressive strength and fracture strain of ∼202–208 MPa, ∼380 MPa, and ∼17% were similar for both the alloy and nanocomposite.

Investigation of Microstructures, Mechanical Properties of AZ91E Hybrid Composite Reinforced with Silicon Carbide and Fly Ash

In this study, the stir casting processing technique was used to produce the AZ91E hybrid composite reinforced with Silicon Carbide (SiC) and Fly ash (FA) particles in different weight percentages varying from 0 to 10%.30 μm in size. This paper investigates the micro structural phenomena and partial mechanical behavior (i.e., tensile strength, hardness, and fracture toughness) of AZ91E alloy reinforced with SiC and FA. Scanning Electron Microscope (SEM) furnished with Energy Dispersive X-ray spectroscopy (EDX) was used to investigate the microstructures. The results show that the SiC and Fly-ash particles are uniformly distributed in the matrix, and there is no sign of SiC and Fly ash agglomerations. The densities of the composites varied from1.805–1.829 g/cm3.The results of hybrid composite samples are then compared with as AZ91E alloy samples. This study found that the addition of both a hard reinforcement (e.g., SiC) and soft reinforcement (e.g., fly ash) remarkably improves the mechanical property such as tensile strength, the hardness of magnesium composites. However, the fracture toughness and elongation of magnesium composites were decreased due to grain refinement due to the addition of reinforcement particles. The tensile test results obtained from the experimental process were compared with finite element method results. The finite element results were in good agreement with the experimental results.

Characteristics of Magnesium/B4C Reinforced Composite Fabricated by Stir Casting Method

At present the development of magnesium composites is increasingly being carried out, this is due to the main advantages of magnesium which has the lowest density when compared with other metals so that it can save fuel use when applied as a constituent of an automotive product yet still has great mechanical properties. In this research, magnesium composite is fabricated by mixing magnesium as composite matrix and micro B4C as reinforcement particle with 2, 4, 6, and 8 Vf-% by stir casting method. The magnesium reinforced B4C particles has improved the mechanical properties of the composite. The best mechanical properties of magnesium composite are shown by the addition of 8 Vf-% B4C particles. These values increase up to 73 HRH for the hardness and 64 MPa for the UTS as well as, 0.11 J / mm2 for the impact value. The wear rate also reduced to 0.0023 mm3/m. The mechanical properties of magnesium composite are increased due to the increasing number of B4C particles thatcaused new interfaces which will block dislocation movement and dispersed B4C particles will also act as load restraint elements. Composite characterization was also carried out by using SEM-EDS and XRD test to find out the compounds and phases formed from the fabricated composites -then it was known that the possible compounds formed from the composites produced were MgB2, MgO, B4C, and Mg2B2O5 respectively.

Computational modeling of degradation process on the mechanical performance of Poly-lactic acid /Magnesium composite

In this study, the corrosion behavior of biodegradable composites is modeled. These composites are made of Poly-Lactic acid and Magnesium with different volume fractions. The scanning electron microscopy images of these composites were taken, and statistical reconstruction of the composite based on scanning electron microscopy images was done by the phase recovery algorithm, the three-dimensional structure of this composite was extracted with this reconstruction, then a three-dimensional cellular automata model was developed to predict the corrosion of this composite. Results of experiments for the composite with 10% of Magnesium volume fraction were used to calibrate the parameters of the cellular automata model, and with these parameters, the results for the composite with 5% of Magnesium volume fraction was obtained, and with comparing these data with the results of the experiment, our model was validated. In the end, we estimated the mechanical properties of these composites and analyzed the results.

Characterization, Mechanical and Wear Behaviour of Magnesium (AZ91D)/Graphite/Tungsten Carbide Hybrid Composites Fabricated by Powder Metallurgy

In this study, magnesium (AZ91D) hybrid composites reinforced with graphite and tungsten carbide were fabricated by compact pressing powder metallurgy technique. Optical microstructure and XRD studies were carried to analyse the distribution of particles and to identify the phases. The mechanical and wear characteristics of the fabricated magnesium (AZ91D) composite samples were studied. The measured density and calculated density of the composites are close to each other indicating minimum porosity. The presence of graphite and tungsten carbide enhances hardness of the composites. Strength of magnesium (AZ91D) composites is higher than the base alloy at room temperature. Addition of tungsten carbide in magnesium composites decreases the wear. Magnesium hybrid composites used in the study exhibit high strength, high hardness and wear resistance.

A review on environment friendly and lightweight Magnesium-Based metal matrix composites and alloys

Magnesium is the lightest metal known on earth has a great potential to be used as a structural alloy. The lightweight alloy and composite property attract the automobile and aerospace companies and provide an alternative to replace the denser metals such as steel, cast iron, zinc alloys and even aluminium alloys. In the present scenario of global warming and increased CO2 content, the introduction of limiting emission legislation has triggered the fascinate in magnesium alloys and its composites. Owing to lowest density, the usage of magnesium has been increased in the last decade and several programs related with processing, development, improvement in design and production field are going on to minimize the emission threat over the environment. This paper aims to discuss briefly followed by examples, the future trends, increasing use of magnesium alloys and composites and its good environmental impacts. So, it was concluded that the overall weight reduction of vehicle by using magnesium-based MMCs and its alloys elucidate the drastic enhancement in its performance in terms of mechanical and tribological behavior which consequently creates a potential for its usage in advanced manufacturing technology for automobile and aerospace sector.

Experimental studies on magnesium metal matrix composites processed by Twist Extrusion

Recently magnesium alloys and magnesium composite were widely used due to their good strength to weight ratio. These materials find its applications in the bio-medical and in aviation industries. The aim of this study is to twist extrude the hybrid magnesium composite. The magnesium AZ91 alloy is used matrix medium and it was reinforced with 2%SiC and 1.5% B4C. The twist extrusion was carried out in a split die with a slope angle of 54°. The composite is prepared by the bottom pouring method. The number of passes is limited to one, as adding the reinforcement increases the brittleness of the composites. The twist extrusion of the composite resulted in a porosity free sample. Hardness was measured by Macro-Vickers tester and ASTM A370 standard was used for the tensile test. Results indicate an increase 26.6% in strength and 38.5% hardness of the twist extruded composite.

Fabrication and characterization of Magnesium Metal Composite by Stir Casting

In Automotive and Aerospace industries, the demand for lighter materials is increasing exponentially. The main advantage of Magnesium Metal Matrix Composites over Aluminium Metal Matrix Composites, there is an additional 15-20% weight saving without having to compromise on properties. Metal matrix composites reinforced with Boron carbide and molybdenum disulphide have significant advantage over conventional materials. Generally, these reinforcements are used to improve the hardness and tensile strength of metal matrix composite. In this study, we have performed three castings each on magnesium alloy (A14Z1, A17Z1, and A19Z1) and composites with reinforcements of 2.5% Boron Carbide by stir casting method. Mechanical test like Rockwell hardness were conducted to find hardness of the specimen. The Microstructure was observed through an Optical Microscope. The comparative study of these samples with and without reinforcement were carried out and analyzed. The results showed that there is an appreciable increase in mechanical and metallurgical properties of new magnesium novel composite material used in this investigation.

Vibration analysis of metal – polymer sandwich structure incorporated in car bonnet

The weight of the car material plays an important role in its performance in terms of fuel efficiency, speed and smoke emission. Especially in hybrid electric vehicles, lightweight materials are important for balancing the weight of its electrical components and also to enhance vehicle speed on account of its comparative low mileage. Nowadays, aluminium, magnesium and Carbon Fibre Reinforced Composites (CFRP) were introduced in making of car body panels since those materials can improve its performance. Yet the material costs, fibre orientation and fabrication techniques in case of CFRP in mass production remains a question. Also, the interior of the car panels was filled with vibration barriers or isolators with considerable thickness which can also add weight to the car. Hence a sandwich structure is presented in this work where the polyurethane foam of higher thickness (core) is bonded between two thin metallic face sheets (skin). The polyurethane foam was chosen as the core because of its low density, porosity and viscoelastic behaviour where it can provide better damping capabilities. Hence, the foam can also help in reducing the volume of internal vibration isolators. Since the car bonnet receives the vibration from sources like aerodynamic exposure to air during travel and mechanical movements within the vehicle (engine operation), it was chosen as the subject for vibration analysis.

Study on surface modification of diamond particles and thermal conductivity properties of their reinforced metal-based (Cu or Mg) composites

An innovative molten-salt method is presented for the in-situ reactive preparation of surface-modified diamond particles. Surface-modified diamond particle reinforced metal-based (copper or magnesium) composites were prepared by spark plasma sintering. Field-emission scanning electron microscopy was used to analyze the surface morphologies of the surface-modified diamond samples and the interfacial bonding of the diamond-metal composite materials. The elemental distributions of the surface-modified diamond particles were analyzed by energy-dispersive X-ray spectroscopy, and X-ray diffraction was used to analyze the phase compositions of the samples. By means of X-ray photoelectron spectroscopy and laser Raman spectroscopy, the surface bonding and graphitization of the surface-modified diamond particles were further analyzed. The results showed that the thickness of the modification layer on the surface of diamond increased gradually with increasing holding time. The surface-modified diamond particle reinforced metal-based composite materials had high thermal conductivities. When the volume percentage of diamond was 35%, the thermal conductivities of the diamond–copper composites were as high as 602 W·m−1·K−1, and the thermal conductivity of the diamond–magnesium composites reached 286 W·m−1·K−1.

Characteristics of composite magnesium with micro SiC particle for automotive applications with stir casting method

Composite is a promoted material consists of two or more materials to enhance the properties mechanically. In this study, composites were created by mixing a matrix; magnesium and the reinforcement; SiC microstructure with the addition of a volume fraction of: 2 %vf, 4 %vf, 6 %vf and 8 %vf. This magnesium composite fabrication process is stirred casting. The results of this study show that the addition of SiC micro particles will enhance the properties of the composite–mechanical wise-, namely, wear resistance and hardness. The addition of SiC micro-reinforcing particles that produced the best magnesium composite was by adding 8 %vf volume fraction which produced a hardness value of 83 HB and a wear rate of 0.002015706 mm3/m. Increased mechanical properties in magnesium composites is caused by the reducing grain size and Orowan strengthening mechanism.

Mechanical Characterization and Corrosion Behaviour of Magnesium and Boron Carbide Composites

Mechanical Characterization and Corrosion Behaviour of Magnesium and Boron Carbide Composites