Ceramic Reinforced Metal Matrix Composites Research Articles

Deposition mechanism of ceramic reinforced metal matrix composites via cold spraying

Understanding the mechanism underlying metal matrix composites (MMCs) in cold spraying is critical to fabricate innovative MMC coatings and deposits with tailored microstructures and excellent mechanical performance. In this work, we propose a systematic numerical simulation framework combined with experimental observations to reveal the co-deposition mechanism of cold-sprayed metal/ceramic MMCs. The finite element modeling results and experimental validation found some critical conclusions regarding the deposition mechanism. The modeling results show that most of alumina particles are significantly fractured in Inconel718/alumina coating in contrast to aluminum/alumina coating. This fact suggests that the critical fragmentation velocity (CFV) of ceramic particles is dependent on the hardness of the metal substrate/matrix. Ceramic particles are more prone to fracture when co-deposited with metals having high hardness. Moreover, the simulation results also indicate that the rebounded alumina particles or fragments are possibly captured by incoming metal particles and trapped into MMCs. Since intact alumina particles are barely seen in composites, especially when co-deposited with hard metals, it can be concluded that direct ceramic particle deposition significantly relies on fragmentation. In addition, secondary fragmentation plays a key role in the metal-ceramic co-deposition process. The particles that have completed the impact process may be subjected to secondary fragmentation in the form of new cracks and fragmentation due to the impact by following metal and ceramic particles.

High-temperature tribological performance of functionally graded Stellite 6/WC metal matrix composite coatings manufactured by laser-directed energy deposition

Wear-driven tool failure is one of the main hurdles in the industry. This issue can be addressed through surface coating with ceramic-reinforced metal matrix composites. However, the maximum ceramic content is limited by cracking. In this work, the tribological behaviour of the functionally graded WC-ceramic-particle-reinforced Stellite 6 coatings is studied. To that end, the wear resistance at room temperature and 400 °C is investigated. Moreover, the tribological analysis is supported by crack sensitivity and hardness evaluation, which is of utmost importance in the processing of composite materials with ceramic-particle-reinforcement. Results indicate that functionally graded materials can be employed to increase the maximum admissible WC content, hence improving the tribological behaviour, most notably at high temperatures. Additionally, a shift from abrasive to oxidative wear is observed in high-temperature wear testing.

Microstructure, mechanical properties and wear behaviors of TiN/Ti composite coating on laser surface textured Ti6Al4V alloy fabricated by MHz picosecond laser surface alloying

Ceramic-reinforced metal matrix composites (MMCs) coating fabricated by laser surface melting effectively improves the surface mechanical and wear properties of titanium alloys. However, power of several hundred watts is generally used in traditional laser processing, which introduces excessive heat input and leads to thermal deformation and thermal effects, resulting in cracks and reducing mechanical properties and service life of coatings. In order to improve the microhardness and anti-wear properties of Ti6Al4V alloy and extend the service life, a picosecond laser (ps-laser) with a power of 23 W and repetition rate of 19 MHz was utilized to fabricate the uniform and crack-free MMCs coating (TiN/Ti) by melting TiN powders on the textured Ti6Al4V surface. Three different textures with different texture densities and depths were used to evaluate their effects on coatings. Results showed that the reinforced TiN phase was in the form of fine dendrites with an average secondary dendrite arm spacing of 0.84 µm. The microhardness and the anti-wear properties were both inversely proportional to the texture densities because of controlling the volume fraction of TiN in the coating. The microhardness of the sample with greatest microhardness increase was significantly improved from 355 HV0.5 (base material) to 1000 HV0.5 due to the addition of the TiN phase. The sample with a texture density of 5% showed the best anti-wear properties (about 22 times that of the substrate) due to the effective suppression of three-body abrasive wear.

A novel ceramic reinforced hierarchical metal matrix composite (Fe/Fe2B): Production and characterization

Lightweight and high strength are the common aspects of ceramic-reinforced metal matrix composites (CMMC) and wire-reinforced composites (WRC). The latter is preferred for enhanced loading response ensured by the presence of extended reinforcements in the metal matrices. Unlike the traditional Al- and Ti-matrix WRC, utilization of composite wires, instead of monolithic wires, as reinforcements for metallic WRC has multiscale engineering benefits. For example, combining the high hardness of the Fe2B and ductility of Fe can benefit tribocomponents where high temperature stability, hardness consistency and adequate toughness is required. Current study investigates the manufacturability of an Fe2B-reinforced Fe-matrix hierarchical WRC using powder metallurgy, in situ phase synthesis, and diffusion bonding. Carefully optimized boriding and diffusion bonding parameters (1100 °C, 2 h, 35 MPa, and 10–20 vol% B4C in Fe powder) assisted in manufacturing a well-bonded WRC; however, diffusion-bonded regions of the wire and sheath-core interfaces within the single-core wires developed carbon-deficient regions. Results showed that increasing fraction of the Fe2B phases within the cores minorly influenced the tensile and bending behavior of wires and WRC, respectively. The wires' tensile strength and WRC's bending fracture loads were decisively influenced by the core diameter of the single-core composite wires, acting as reinforcement. Additionally, while cores developed transverse cracks, the critical inter-wire and sheath-core interfaces preferably failed with longitudinal cracks due to the presence of carbon-deficient regions at the interfaces.

Manufacturing of Ceramic Reinforced Metal Matrix Composites (Al/Sicp) And Their Characterization Through Powder Metallurgy Methods

Metal Matrix Composites is two or more combination material with aluminum metal as matrix and devolved to fix metal act, strength, high temperature stability and hardness. Metal matrix composites have been developed so many because it has low density, corrosion proof, cheap and easy fabrication. Powder metallurgy technique is one of metal matrix composites fabrication process in solid state that is still developed because more economic, doesn't need difficult equipment. Aluminum that use in this research is Al alloy type 2124. Metal matrix composites fabrication process with powder metallurgy method using wet mixing with pure ethanol, cold compaction 300 MPa and inert gas atmospheric using Nitrogen gas (N2) at sintering process. Variation of sinter temperature that used is 450, 500, 550, and 600 oC with highly temperature average 5 oC/min and holding time for 1 hour and with speed flow Nitrogen gas (N2) 5 lt/min with pressure 1000 kgf/cm2. From research result can be concluded the mechanical properties and physical properties from metal matrix composites reinforced ceramics Al/SiCp increase with sinter temperature highly and with reinforcement particle addition SiC can increase mechanical properties and physical properties such as: hardness, wear resistance, coefficient of thermal expansion and corrosion resistance. From microstructure analysis, particle Sic distributed homogeneously at test specimen based on SEM analysis, and structure crystal analysis test result XRD show that dominant phase appear is Al, and Sic.

Effect mechanism of mono-particles or hybrid-particles on the thermophysical characteristics and mechanical properties of Cu matrix composites

The nature of ceramic particles plays a decisive role in the performance of the ceramic/metal composites. This work is designed to deeply analyze the effect of mono-particles and hybrid-particles on the thermal and mechanical characteristics of the composites by means of experiment and finite element analysis. The in-situ TiB2/Cu and (TiC + TiB2)/Cu composites were fabricated by reactive hot pressing in Cu–Ti–B and Cu–Ti–B4C reaction systems. The two kinds of composites have similar coefficient of thermal expansion, while the (TiC + TiB2)/Cu composite demonstrates higher thermal conductivity and better compression properties than the TiB2/Cu composite. Simulations suggest that the spherical TiC particles in the (TiC + TiB2)/Cu composite optimize the heat transfer path and improve the stress distribution and plastic deformation, which are the main reasons for the difference in composite properties. Besides, the TiB2/Cu composite demonstrates excellent wear resistance due to the pinning effect of the hexagonal columnar particles. This would help deepen the understanding of the strengthening mechanism of mono-particles or hybrid-particles ceramic reinforced metal matrix composites and have a significant guiding role in the microstructure design and synergy optimization of composite.

Wear Resistance of Aluminum Matrix Composites’ Coatings Added on AA6082 Aluminum Alloy by Laser Cladding

Ceramic-reinforced metal matrix composites are known for their high wear resistance. A coating based on these materials would be helpful to improve the wear behavior of aluminum alloys. Laser cladding has been used to deposit a coating consisting of an aluminum alloy reinforced with SiC particles on an AA6082 aluminum alloy. Laser cladding is a very energetic technique that causes the SiC particles to react with the molten aluminum to form Al4C3, which degrades the particles and reduces the properties of the coating. The formation of this detrimental compound was successfully achieved with the addition of Silicon and Titanium to the composite matrix. The microstructures of the newly developed material were characterized and the wear behavior was studied under dry sliding conditions on a pin-on-disc tribometer. The relationship between the microstructure and wear behavior was identified. The absence of Al4C3 in the Al40Si/SiC and Al12Si20Ti/SiC coatings’ microstructures resulted in an abrasion mechanism instead of a delamination mechanism. The wear behavior changed along the sliding distances. During the first 200 m of sliding distances, the wear rate of all coatings was lower than the uncoated one due to their higher microhardness. For longer sliding distances, the wear resistance of the uncoated AA6082 was higher than the coated ones due to the formation of a lubricant oxide layer on the AA6082 worn surface. For 1000 m of wear distances, the wear behavior was different for each coating. The wear rate of the Al12Si/SiC coating continued growing due to the delamination mechanism and the presence of Al4C3 that acted as starting crack points. The wear rate of the Al40Si/SiC coating decreased due to the formation of a thin, superficial oxide layer. The wear rate of the Al12SiTi/SiC progressively decreased along the sliding distance to below the substrate wear rate.

Laser Coatings via State-of-the-Art Additive Manufacturing: A Review

Ceramics and ceramic-reinforced metal matrix composites (CMMCs) demonstrate high wear resistance, excellent chemical inertness, and exceptional properties at elevated temperatures. These characteristics are suitable for their utilization in biomedical, aerospace, electronics, and other high-end engineering industries. The aforementioned performances make them difficult to fabricate via conventional manufacturing methods, requiring high costs and energy consumption. To overcome these issues, laser additive manufacturing (LAM) techniques, with high-power laser beams, were developed and extensively employed for processing ceramics and ceramic-reinforced CMMCs-based coatings. In respect to other LAM processes, laser melting deposition (LMD) excels in several aspects, such as high coating efficiency and lower labor cost. Nevertheless, difficulties such as poor bonding between coating and substrate, cracking, and reduced toughness are still encountered in some LMD coatings. In this article, we review recent developments in the LMD of ceramics and CMMCs-based coatings. Issues and solutions, along with development trends, are discussed and summarized in support of implementing this technology for current industrial use.

Mechanisms of laser energy absorption and melting behavior during selective laser melting of titanium-matrix composite: role of ceramic addition

The laser energy absorption and melting behavior of ceramic reinforced metal matrix composites during selective laser melting (SLM) additive manufacturing are vital for the subsequent metallurgical behavior. In this study, the mesoscopic simulation was proposed to investigate the influence of ceramic addition on the laser energy absorption and powder melting behaviors during SLM of TiC/Ti6Al4V composites. As the addition of TiC particles increased from 0 wt.% to 5 wt.%, the packing density of composite powder increased from 2.357 g cm−3 to 2.588 g cm−3, while the hall velocity decreased from 36.00 s to 73.14 s, indicating the powder flowability decreased with the ceramic addition. Meanwhile, the number of laser-powder interactions increased from 1.267 × 106 to 1.626 × 106, thereby enhancing the laser multiple reflection phenomenon in the powder bed. The concentrated irradiance distribution on the metal powder was dispersed into the surrounding powder. The average irradiance intensity on TiC particles was continuously improved, which increased the overall laser absorptivity from 0.655 to 0.72, yielding an elevated maximum operating temperature within the molten pool from 3501 K to 3668 K. However, with the excessive addition of ceramics (5 wt.%), balls and trapped unmelted particles deteriorated the surface morphology of the melted track. It can be attributed to the high required energy for complete melted TiC and the elevated difficulty of completely wetting unmelted particles. These results provided the physical understanding of high-quality and defect-free components of SLM processed composite materials.

High strength-ductility synergy of MgAlB4 whisker reinforced aluminum matrix composites achieved by in situ synthesis

For ceramic reinforced metal matrix composites, it is a critical issue to improve the limited ductility to achieve a combination of high strength and high toughness. Herein, in-situ synthesized MgAlB4 whisker reinforced Al (MgAlB4w/Al) composites with rational distribution of the reinforcement were successfully prepared by an efficient process combining vacuum pressureless sintering and hot-extrusion. The results demonstrate that the MgAlB4 whiskers noticeably coarsen with increasing sintering temperature, while the sintering duration has little effect on the size of the whiskers. The as-extruded composite with 15 wt% MgAlB4w has excellent comprehensive properties with the ultimate tensile strength of 380 MPa and the fracture elongation of ~9.6%. Fracture analysis reveals that the whiskers bear most loads and fracture firstly to form crack sources with the load increasing during drawing. In addition, the alignment distribution of MgAlB4w along extrusion direction is the main reason for the improved ductility of the MgAlB4w/Al composite.

Design of binder jet additive manufactured co-continuous ceramic-reinforced metal matrix composites

Ceramic-reinforced metal matrix composites (MMCs) display beneficial properties owing to their combination of ceramic and metal phases. However, the properties are highly dependent on the reinforcing phase composition, volume fraction and morphology. Continuous fiber or network reinforcement morphologies are difficult and expensive to manufacture, and the often-used discontinuous particle or whisker reinforcement morphologies result in less effective properties. Here, we demonstrate the formation of a co-continuous ceramic-reinforced metal matrix composite using solid-state processing. Binder jet additive manufacturing (BJAM) was used to print a nickel superalloy part followed by post-processing via reactive sintering to form a continuous carbide reinforcing phase at the particle boundaries. The kinetics of reinforcement formation are investigated in order to develop a relationship between reactive sintering time, temperature and powder composition on the reinforcing phase thickness and volume fraction. To evaluate performance, the wear resistance of the reinforced BJAM alloy 625 MMC was compared to unreinforced BJAM alloy 625, demonstrating a 64 % decrease in the specific wear rate under abrasive wear conditions.

Casting temperature dependent wear and corrosion behavior of 304 stainless steel reinforced A356 aluminium matrix bimetal composites fabricated by vacuum-assisted melt infiltration casting

This study aims to determine optimum casting temperature to achieve maximum wear and corrosion resistance in 304 stainless steel (SS) reinforced A356 matrix bimetal composites, which have been developed for use where conventional ceramic reinforced metal matrix composites have been used. Vacuum-assisted melt infiltration casting technique was used to manufacture bimetal composites at the various casting temperatures from 630 °C to 880 °C. The composite samples were subjected to dry sliding ball-on-disc tests using Al2O3 ball and immersion test in 3.5% NaCl solution for 7–21 days. θ (Fe4Al13) and η (Fe2Al5) phases developed at A356/304 interfaces and thickened with increasing temperature. Abrasion and adhesion as predominant wear mechanisms were observed in worn surface examinations, while pitting and galvanic corrosion occurred in corroded surfaces. The most suitable casting temperature was found to be 730 °C, considering the wear and corrosion properties of produced bimetal composites under certain conditions.

Microstructure evolution of in-situ (Ti,W)C-Al2O3 particle-reinforced alloy fabricated by gas tungsten arc cladding

This paper reports the fabrication of TiC-Al2O3 or (Ti,W)C-Al2O3 ceramic reinforced metal matrix composites (MMC) using gas tungsten arc cladding. For fabrication of the MMC, an in-situ reaction was used to reduce oxides by employing C and Al as reducing materials during the cladding process, and the strengthened particles formed on the surface by solid state reaction were then grown through interaction in the metal matrix. The reactions forming phases in this system were subsequently examined through thermodynamic calculations. Results showed that TiC and Al2O3 peaks were observed in XRD for the reduction of TiO2 and WO3 by Al and C. The cladded hardfacings were covered by a composite slag zone, which consisted of Al2O3 particles embedded in Al and Ti based ceramic matrix, and that carbide particles such as TiC and (Ti,W)C were distributed intensively inside the MMC zone. Most of the TiC particles in the MMC zone had a slow growth rate because the interface controlled the growth; however, some particles that highly interacted with metals exhibited a dendrite structure. (Ti,W)C particles without dendrite growth formed a spherical shape, and the size of the particles was controlled by diffusion of the solute. Following the dissolution and precipitation process, (Ti,W)C-strengthened particles were found to have a sintering-like core/rim structure. Furthermore, the microhardness of the clad obtained was 600–900 HV0.2, which is significantly better than that obtained with commercial TiC powder.

High-performance joining technology for aluminium matrix composites using ultrasonic-assisted brazing

ABSTRACTHigh-performance aluminium matrix composite joints were fabricated using a new joining technology assisted by ultrasonic vibration. The performance of the joints was close to that of the parent materials. The microstructure and the mechanical performance were found to be systematically dependent on the volume fraction and the distribution of reinforcement particles in the bond region. The authors believe that this study can be generalised to the bonding of other ceramic-reinforced metal matrix composites.

The Influence of the Particle Size on the Adhesion Between Ceramic Particles and Metal Matrix in MMC Composites

This study investigated the influence of the particle size on the adhesion force between ceramic particles and metal matrix in ceramic-reinforced metal matrix composites. The Cu-Al2O3 composites with 5 vol.% of ceramic phase were prepared by a powder metallurgy process. Alumina oxide powder as an electrocorundum (Al2O3) powder with different particle sizes, i.e., fine powder <3 µm and coarse powder of 180 µm was used as a reinforcement. Microstructural investigations included analyses using scanning electron microscopy with an integrated EDS microanalysis system and transmission microscopy. In order to measure the adhesion force (interface strength), we prepared the microwires made of the investigated materials and carried out the experiments with the use of the self-made tensile tester. We have observed that the interface strength is higher for the sample with coarse particles and is equal to 74 ± 4 MPa and it is equal to 68 ± 3 MPa for the sample with fine ceramic particles.

The measurement of the adhesion force between ceramic particles and metal matrix in ceramic reinforced-metal matrix composites

This paper presents the method for measurement of the adhesion force and fracture strength of the interface between ceramic particles and metal matrix in ceramic reinforced-metal matrix composites. Three samples with the following Cu to Al2O3 ratio (in vol.%) were prepared: 98.0Cu/2.0Al2O3, 95.0Cu/5.0Al2O3 and 90Cu/10Al2O3. Furthermore, microwires which contain a few ceramic particles were produced by means of electro etching. The microwires with clearly exposed interface were tested with use of the microtensile tester. The microwires usually break exactly at the interface between the metal matrix and ceramic particle. The force and the interface area were carefully measured and then the fracture strength of the interface was determined. The strength of the interface between ceramic particle and metal matrix was equal to 59±8MPa and 59±11MPa in the case of 2% and 5% Al2O3 to Cu ratio, respectively. On the other hand, it was significantly lower (38±5MPa) for the wires made of composite with 10% Al2O3.

Fabrication and heat treatment of ceramic-reinforced aluminium matrix composites - a review

Abstract Ceramic-reinforced aluminium matrix composites have attracted considerable attention in engineering applications as a result of their relatively low costs and characteristic isotropic properties. Reinforcement materials include carbides, nitrides and oxides. In an effort to achieve optimality in structure and properties of ceramic-reinforced metal matrix composites (MMCs), various fabrication and heat treatment techniques have evolved over the last 20 years. In this paper, the status of the research and development in fabrication and heat treatment techniques of ceramic-reinforced aluminium matrix composites is reviewed, with a major focus on material systems in terms of chemical compositions, weight or volume fraction, particle size of reinforcement, fabrication methods and heat treatment procedures. Various optical measurement techniques used by the researchers are highlighted. Also, limitations and needs of the technique in composite fabrication are presented in the literature. The full potential of various methods for fabricating ceramic-reinforced aluminium matrix composites is yet to be explored.

Microstructure and mechanical properties of 6061 Al alloy based composites with SiC nanoparticles

Materials with high specific strengths as well as damage tolerance are of great importance for automotive and aerospace applications. Ceramic reinforced metal matrix composites (MMCs) show good potential for these uses but have been hampered by insufficient ductility and production issues, both of which this work looks to resolve. Nanoparticle reinforced 6061 aluminium alloy matrix composites have been produced by a powder metallurgy route and shown to exhibit high strength and Young’s modulus alongside good ductility and low density.A powder metallurgy route consisting of high energy ball milling, hot isostatic pressing (HIP) and extrusion has proved a highly effective process for achieving a homogeneous distribution of particles, with minimal clustering of the nanoparticles, at an industrially relevant scale. After heat treatment the composites display high strengths, owing to SiC nanoparticle reinforcement as well as the age hardening effect. The remarkable feature of nanoparticle reinforced MMCs compared to micron size reinforcements is that particle fracture does not occur and effective particle–matrix bonding can be taking place, resulting in a greater combination of strength and toughness.The combination of properties achieved by the composites studied in this work are superior to most of the micron sized particle reinforced MMCs reported elsewhere and are well beyond what is possible with traditional aluminium alloys.

Role of friction stir welding parameters on tensile strength of AA6061–B4C composite joints

Friction stir welding (FSW) is a solid state joining technique developed to join high strength aluminum alloys and various ceramic reinforced metal matrix composites (MMCs). FSW produces sound welds in MMCs without any deleterious reaction between reinforcement and matrix. The present work focused on the effect of FSW parameters on the tensile strength of Al-B4C composite joints. The central composite design of four factors and five levels was used to control the number of experiments. A mathematical model was developed to analyze the influence of FSW parameters. The results indicated that the joint fabricated using rotational speed of 1000 r/min, welding speed of 1.3 mm/s, axial force of 10 kN and the reinforcement of 12% showed larger tensile strength compared with the other joints. The developed model was optimized to maximize the tensile strength using generalized reduced gradient method. The metallographic analysis of the joints showed the presence of various zones such as weld nugget (WN) zone, thermo mechanically affected zone (TMAZ) and heat affected zone (HAZ). The substantial grain refinement of aluminum matrix as well as significant size reduction of B4C particles was observed in the weld nugget. TMAZ was plastically deformed, thermally affected and exhibited elongated aluminum grains.

Interfacial Criteria to Avoid Pushing of Particles during Solidification of Metal Matrix Composites

The interfacial criterion to avoid pushing of particles during solidification of ceramic reinforced metal matrix composites (MMCs) at low rates of the solidification has been found as: i for liquid alloys with at least one interface-active solute (at the melt/particle interface) the engulfment of particles is always ensured by the interfacial energy gradient caused by solute build-up; ii. for pure metals and for alloys with no interface-active components engulfment is ensured if the following condition is fulfilled: Δσ = 2σ cs - σ cl - σ sl < 0 (where σ is the interfacial energy, J/m 2 , and lower indexes indicate the phases in contact: c is for ceramic particle, s is for solid metal and l is for liquid metal A new model is derived to estimate the interfacial energy between solid metal and solid ceramics. Based on this model, the pushing-engulfinent diagrams have been constructed.