Particle Reinforced Metal Matrix Composites Research Articles

Observing and Modeling the Wear Process of Heterogeneous Interface.

Understanding and controlling the wear process of heterogeneous interfaces between soft and hard phases is crucial for designing and fabricating materials, such as improving the wear resistance of particle reinforced metal matrix composites and the accuracy and efficiency of chemical mechanical polishing. However, the wear process can be hardly observed, as interfaces are buried under the surface. Here, we proposed a nanowear test method by combining focused ion beam cutting to expose interfaces, atomic force microscopy to rub against interfaces, and scanning electron microscope to characterize the interface damage. Using this method, three typical wear forms had been observed in Al/SiC composite, i.e., merely matrix wear, particle fracture, and particle pullout. A theoretical model was proposed that revealed that the increasing interfacial friction would induce particle fracture or pullout, depending on the particle edge angle and tip edge angle. This work sheds light on wear control in composites and nanofabrication.

Ultrafast fabrication of W/Cu composites using flash sintering

When the proportion of reinforcing phases is high and the wettability between the secondary phase and the metal is poor, preparing fully dense particle-reinforced metal matrix composites becomes challenging. This study employs the flash sintering method to prepare fully dense WCu20 composite materials within a few tens of seconds. It is found that during the “thermal runaway' process of flash sintering, the Cu phase undergoes rapid melting and solidification, and the core mechanism of material densification is that pressure causes Cu liquid to quickly fill the gaps between tungsten particles. Pressure not only promotes the contraction of the framework formed by tungsten particles but also facilitates the complete filling of gaps within the tungsten frameworks by the Cu liquid and promotes the rapid expulsion of bubbles from the Cu liquid, thereby achieving rapid densification of WCu20 composite materials. Moreover, an increase in the temperature enhances the fluidity of the Cu liquid, which aids in filling the gaps between tungsten particles and promotes the discharge of bubbles from the Cu liquid. Flash sintering is a common technique for the sintering and densification of metal powders, suitable for the rapid preparation of various metal matrix composites.

Ultra-high strength metal matrix composites (MMCs) with extended ductility manufactured by size-controlled powder and spherical cast tungsten carbide

The main challenge of particle reinforced metal matrix composites (MMCs) is balancing strength and ductility. This research uses type 420 stainless steel and spherical cast tungsten carbide (WC/W2C) with a similar powder size and range as raw powders to manufacture laser powder bed fusion (LPBF) 420 + 5 wt% WC/W2C MMCs. LPBF 420 + 5 wt% WC/W2C MMCs contain austenite, martensite, and W-rich carbides (WC/W2C, FeW3C, M6C, and M7C3) from nanometre to micrometre scale. The well-balanced composition creates a crack-free reaction layer between the reinforced particles and matrix. This reaction layer consists of two distinct layers, depending on the element concentration. The LPBF 420 + 5 wt% WC/W2C MMCs achieved an excellent compressive strength of ∼5.5 GPa and a considerable fracture strain exceeding 50 %. The underlying mechanisms for the improved mechanical properties are discussed, providing further insight to advance the application of MMCs via additive manufacturing.

Regulating the microstructure of Ti@TiAlSi core-shell structured reinforcing particles endows Al–Si alloy matrix composites with high strength and ductility

Forming spherical core-shell (CS) structured reinforcing particles, consisting of a Ti core and a surrounding TiAlSi intermetallic shell, by in situ reaction between Ti and Al matrix is a promising approach to overcome the strength-ductility trade-off in particle reinforced Al–Si matrix composites. However, the phase constituent and microstructure of the shells are highly sensitive to the Al–Si alloy composition and processing parameters of the powder thixoforming method. Therefore, the effects of Si content and partial remelting temperature on the microstructure of CS particles and the tensile properties of the resultant composites were investigated in this study. The results indicate that uniform and compact shell can be achieved only by the τ2-phase reaction layer generated during partial remelting. To form the τ2 phase, the Si content in the liquid phase of the semisolid billet prior to thixoforming must be higher than 10.3 wt%. This can be achieved through adjusting the Si content in the Al–Si alloy matrix or/and partial remelting temperature. Moreover, the Ti core radius to shell thickness ratio of ∼1.5 was proposed to achieve the composites with both high strength and ductility. These findings are helpful for designing the microstructure and fabricating CS particles reinforced metal matrix composites with excellent comprehensive mechanical properties.

Enhanced wear resistance of TiC/Ti6Al4V composites through changing TiC morphologies in laser direct energy deposition

The wear performance of particle-reinforced metal matrix composites is significantly influenced by the morphologies of ceramic particles. In this study, the friction and wear characterization of titanium matrix composites (TMCs) with different TiC morphologies was studied. This TMCs, consisting of 20 wt% of TiC, was prepared by laser direct energy deposition (LDED). Different LDED parameters are employed to changing the morphologies of TiC. Two distinct TiC morphologies, equiaxed and dendritic, are achieved by varying the laser scanning speed and laser power during the LDEDed TMCs. The friction and wear tests of TMCs with different TiC morphologies are carried out by using a ball-on flat reciprocating tribometer. The results reveal that TMCs with different TiC morphologies manifest divergent wear mechanisms. TMCs with equiaxed TiC dominates three-body wear due to the fracture debonding and pulling out of TiC, resulting in a higher wear rate. TMCs with dendritic TiC mainly dominates two-body wear, facilitated by the protection of hard dendrites and the tribolayer, which leads to a 59% improvement in wear resistance compared to TMCs with equiaxed TiC. This work provides a method of TiC morphologies changing to achieve an enhanced wear performance for TMCs.

Selective laser melting and mechanical behavior of Mo-coated diamond particle reinforced metal matrix composites

Defects, such as pores, microcracks, and thermal damage, pose significant challenges in the selective laser melting (SLM) process of diamond reinforced metal matrix composites. To address these issues, this study utilizes Mo-coated diamond particles prepared via salt bath plating for SLM processing of CoCr-diamond composites. The SLM process parameters including laser power, scanning speed, and hatch spacing were systematically optimized using the response surface method (RSM). Subsequently, the microstructure and mechanical properties of the SLMed CoCr-diamond composites were thoroughly investigated. Notably, a protective layer of Mo2C is formed on the surface of diamond particles during the salt bath plating process. When compared to the SLMed CoCr-15 vol% Mo-uncoated diamond composite, the Mo coating significantly enhances the compressive strength by 69 % and flexural strength by an impressive 345 % for the CoCr-15 vol% Mo-coated diamond composite.

Effect of Graphene Particle Diameter on Mechanical Properties of Graphene Composite Material

In order to improve the mechanical properties of alloys and broaden their application fields, high-performance metal matric composites have received more and more attention. Graphene has excellent mechanical properties and is often used as a reinforcing phase for various composite materials. However, as the reinforcing phase of the composite, the number, shape, and size of graphene have a significant effect on the overall mechanical properties of the composites. Therefore, the influence of graphene particle diameter on the mechanical properties of graphene particle reinforced metal matrix composites was studied in this paper. By establishing a series of finite element models, we simulated the mechanical behaviour of composite materials under static tension loading. The relationship between graphene particle diameter and material mechanical properties is revealed.

Advancing heat-tolerant composites with coherent ladder interfaces via constructing extremely fine nanolamellar solute-twining architectures

The interface of ceramic particles and metal matrixes extremely impacts the mechanical properties of particle-reinforced metal matrix composites, especially at elevated temperatures. We provide a strategy for constructing extremely fine, in situ-formed coherent nanolamellar solute-twining architectures in a supersaturated MAX/Ni composite to modify the interface, aiming for higher strengths. Through this unique architecture, a coherent interface of ceramic particles and a metal matrix is formed, with an enormous coherent interface known as a ladder interface. The tensile strength at 1023 K is approximately 1 GPa by forming a thermally stable Schwarz crystal structure (< 3 nm). Developing heat-tolerant composites using this architecture may enhance the materials’ available properties for high-temperature applications.

Optimization of wire spark erosion machining of Grade 9 titanium alloy (Grade 9) using a hybrid learning algorithm

Manufacturing has grown challenging because of the increased usage of harder materials, such as titanium alloys, in many industries, such as aerospace, automobiles, and marine. Conventional material removal procedures are not suitable for these tough materials due to their increased hardness and slow machinability. Wire Electrical discharge machining (WEDM) is a modern approach for material removal, particularly for harder materials, such as titanium alloys, nickel alloys, hard particle reinforced metal matrix composites, etc. The research design was performed by deeming the independent factors, such as duration of pulse and applied current. The removal rate of material, surface roughness of the machined region, dimensional deviation, and tolerance errors in form/orientation are considered performance metrics. Taguchi’s approach was engaged to assess the process variables, and the importance of the process factors was established using analysis of variance approach. The purpose of this research is to create an AI based decision making tool, which can be utilized to anticipate the various parameters that impact the WEDM material removal process. The discoveries of the present exploration allowing the manufacturers to make better-informed decisions with a developed model’s capability by demonstrating that the model’s predicted values were in close confirmation to the actual values.

Influence of surface integrity on the fatigue performance of TiB2/Al composite treated by ultrasonic deep rolling: Experiments and simulations

The influences of surface integrity on the fatigue performance of in-situ 6 wt% TiB2/2024Al composite treated by ultrasonic deep rolling (UDR) were comprehensively investigated with both experiments and simulations. Results reveal that only a single pass of UDR treatment can impressively reduce the surface roughness of the fine-turned specimens by 94 %. Moreover, axial compressive residual stress (RSc) larger than −400 MPa and strain hardening (SH) higher than 50 % were obtained on the surface. The comprehensive effect of these surface integrity improvements has enhanced the fatigue limit by 22 %, extended the fatigue life by 10∼20 times, and expanded the safe region in the Goodman-Haigh graph by 14.6 %. More importantly, UDR significantly dispersed the TiB2-particle aggregates in the composite surface, which provided the possibility of improving the surface comprehensive mechanical properties of particles reinforced metal matrix composites (PRMMCs) through a simple and convenient mechanical way.

Computational damage analysis of metal matrix composites to identify optimum particle characteristics in indentation process

This paper presents an integrated numerical model that investigates the effects of Al2O3 particle volume fraction, distribution, size, shape, and clustering on the deformation, damage, and failure behaviors of particle-reinforced metal matrix composites. Additionally, the effects of the cohesive strength of the matrix-particle interface and the initial void volume fraction on these behaviors are investigated. In this study, random microstructure-based finite element modeling approach is used. The Gurson-Tvergaard-Needleman model is used to capture the plastic deformation and ductile cracking of the matrix, whereas the Johnson–Holmquist II model is used to model particle fracture. The matrix-particle interface decohesion is modeled using the surface-based cohesive zone method. A two-dimensional nonlinear finite element model augmented with Python-generated code is developed in ABAQUS/Explicit to analyze the damage mechanisms in AA6061-T6/Al2O3 particle-reinforced metal matrix composites. The results show that Al2O3 particle enhance the ability of particle-reinforced metal matrix composites to resist deformation. However, this enhancement is dependent on the indentation location, particulate characteristics, and the applied load. An increase in the particle volume fraction increases the risk of particle fracture, particularly when particles are close to the material surface. Circular particles are the optimal choice for the reinforcement of particle-reinforced metal matrix composites. The predictions are in good agreement with the experimental data, particularly in terms of Rockwell hardness and deformation characteristics.

Enhanced machinability of aluminium-based silicon carbide by non-resonant vibration-assisted magnetorheological finishing

Aluminium-based silicon carbides (SiCp/Al) have been widely used due to their inherent unique physical and mechanical properties. However, improving the surface quality is challenging as finishing cannot meet the requirements of removing the height differences caused by the SiC and aluminium phases. This study aims to investigate the effectiveness of non-resonant vibration-assisted magnetorheological finishing (NVMRF) in reducing the referred height differences and then to enhance the surface quality. Finite element modeling (FEM) and molecular dynamics (MD) simulations were utilized to analyze the influence of the vibration on the fragmented particles as well as the reduction of two-phase height difference. Nano scratch experiments reveal the removal mechanism of the SiC phase in NVMRF. A material removal rate (MRR) model considering the influence of the exerted forces of abrasive particles and the concept of micro-removal mechanism was established. When analyzing the machining results, it was found that the plastic removal in the SiC phase contributed to the NVMRF. Besides, it was verified that the vibration-induced tangential force effectively reduced the height difference. Although there is a slight discrepancy between the theoretical and experimental values of the finishing force within the experimental parameters, the consistent trend confirms the effectiveness of the proposed method. Finally, this research provides a valuable method for finishing the particle-reinforced metal matrix composites (PRMMCs).

An Al–Mg layered double oxide architectured Al2O3/AZ91D composites in balancing the strength-ductility trade-off

The strength-ductility trade-off has long challenged particle-reinforced metal matrix composites (MMCs). This paper presents an Al–Mg layered double oxide (LDO consisted of Al2O3(1 2‾10)//MgAl2O4(004)//MgO(002) at the Al2O3 side, and a MgO(200)//Mg(1 1‾02) the Mg matrix side) architectured Al2O3/AZ91D composite. The intermediate LDO bonds the inner hard Al2O3 reinforcement and the soft AZ91D matrix, which is beneficial to the trade-off between strength and plasticity of ceramic particle reinforced MMCs. An effective load-transfer enhancement and easy dislocation-bypass across the LDO with a set of coherent pairs (Al2O3–MgAl2O4, MgAl2O4–MgO, MgO–Mg, contributes to this synchronization improvement of strength and plasticity. This work sheds some light on fabricating Mg matrix composites with high strength and ductility.

Strategies and Outlook on Metal Matrix Composites Produced Using Laser Powder Bed Fusion: A Review

Particle-reinforced metal matrix composites (MMCs) produced using the laser powder bed fusion (LPBF) technique have gained considerable attention because of their distinct attributes and properties in comparison with conventional manufacturing methods. Nevertheless, significant challenges persist with LPBF-fabricated MMCs: more design parameters over commercially available alloys and several defects resulting from inappropriate process conditions. These challenges arise from the intricate interaction of material- and process-related phenomena, requiring a fundamental understanding of the LPBF process to elucidate the microstructural evolution and underlying mechanisms of strengthening. This paper provides a comprehensive overview of these intricate phenomena and mechanisms, aiming to mitigate the process-related defects and facilitate the design of MMCs with enhanced mechanical properties. The material processing approach was suggested, covering from material design and LPBF to postprocessing. Furthermore, the role of in situ heat treatment on the microstructure evolution of MMCs was clarified, and several novel, potential strengthening theories were discussed for the LPBF-fabricated MMCs. The suggested strategies to address the challenges and design high-performance MMCs will offer an opportunity to develop promising LPBF-fabricated MMCs, while overcoming the material limitations of LPBF.

The Effect of Processing Techniques and Operating Parameters on the Erosion Wear Behavior of Particle-Reinforced Metal Matrix and Surface Composites: A Review

The Effect of Processing Techniques and Operating Parameters on the Erosion Wear Behavior of Particle-Reinforced Metal Matrix and Surface Composites: A Review

High-strength, high-toughness SiCp reinforced Mg matrix composites manufactured by semisolid injection molding

Particle-reinforced Mg matrix composites possess excellent mechanical and physical properties. In this study, a new processing technique, semisolid injection molding, was employed to fabricate SiCp/AZ91D composites. The microstructure and mechanical properties of the as-molded composites were investigated. The SiC particles were found to be uniformly distributed in the metal matrix and no agglomeration was observed. The presence of small voids next to the SiC particles was observed. The microhardness of the composites decreases with the increase of SiC content, and initially decreases and then increases to a stable level with the increase of casting temperature. The 2.5 wt% SiCp/AZ91D composite has the highest tensile strength, up to 10% higher than AZ91D and 18% higher than the 1 wt% SiCp/AZ91D composite. A large number of small dimples and spherical voids, formed after unmelted Mg particles were pulled out of the matrix, were observed on the tensile fracture surface. This study demonstrates that semisolid injection molding is a valuable technique for the manufacture of particle-reinforced metal matrix composites.

Microstructure-based simulation on the mechanical behavior of particle reinforced metal matrix composites with varying particle characteristics

The mechanical performance of metal matrix composites strengthened with particles is predominantly contingent upon the attributes of the incorporated particles. Attaining the optimal particle size, morphology, and interfacial bonding within the composites is paramount for improving the comprehensive properties. In this study, an experimentally congruent model was devised to validate the feasibility of the model predicated on the actual microstructure of the composite. The modeling procedure encapsulated matrix and particle failure, as well as surface-based cohesive damage at the interface, to precisely portray the mechanism of action for the particle characteristics. Additionally, the mechanical behavior and failure evolution mechanism of the composites were simulated by manipulating the pertinent particle factors, including size distribution, interfacial strength, and morphology. The findings demonstrated that an appropriate size distribution between particles and more rounded particles can mitigate stress and strain concentration within the matrix interstitial to particles, resulting in a considerable enhancement in the mechanical performance of the composites. As the interfacial strength decreases, the initial failure progression of the composite shifts from initial cracking within the matrix induced by stress-strain concentration to interfacial failure caused by interfacial debonding, ultimately accelerating the failure of composite. This research will bolster the comprehension of the correlations between microstructural features and mechanical performance in metal matrix composites strengthened with particles, providing an innovative simulation-assisted experimental approach for the rapid development and preparation of novel metal matrix composites.

Configuration feature extraction and mechanical properties prediction of particle reinforced metal matrix composites

Improving the strength-toughness matching properties has become a key issue in metal matrix composites, which can be achieved by some specific designs of composite configurations (i.e. spatial distribution of reinforced particles). To better interpret the composite configuration effect on mechanical properties, it is necessary to develop comprehensive feature descriptors for composite configurations. In this work, topological data analysis and particle clustering parameter are applied to extract feature descriptors for composite configurations of SiCp/Al composites, which are effective to distinguish different types of composite configurations. In addition, based on the dataset constructed by finite element analysis, machine learning algorithms are applied to predict the composite configurations-mechanical properties of SiCp/Al composites. Then, particle swarm optimization is used to search the composite configurations with extreme mechanical properties predicted by machine learning model. The results of this work indicate that the composite configurations with larger particle clustering parameter and persistent entropy will yield better strength-toughness matching.

Microstructure-based 3D finite element modeling of deformation and damage of (ZrB2+B4C)/6016Al hierarchical composites

In this study, the mechanical behavior, with dislocation “punched zone” (strengthened microzone by particles) emphasis on the damage mechanisms of (ZrB2+B4C)/6016Al hierarchical composites was studied by both experiments and finite element analysis. The experimental results show that the introduction of nanoparticles is an effective strategy to strengthen work hardening ability, as well as the tensile mechanical property of the hierarchical composites. Establishing the microstructure-based three-dimensional (3D) finite element model considered the reinforcement distribution and the dislocation “punched zone” of the matrix, which was identified by the nano-indentation test. The model was employed to reveal the deformation behavior and damage mechanism of the (ZrB2+B4C)/6016Al hierarchical composites by analyzing the stress and strain distributions. The elastoplastic response behavior simulation was conducted by changing the content of both reinforcements to accurately predict the composites' mechanical properties. This work proposes the strategy of introducing nano reinforcements to the unreinforced zone in traditional particle reinforced metal matrix composites (PRMMCs) to improve the microzone coordinated deformation as well as provides a reference for studying and optimizing the mechanical property of hierarchical composites via microstructure-based modeling.

Processability of A6061 Aluminum Alloy Using Laser Powder Bed Fusion by In Situ Synthesis of Grain Refiners

Despite the increasing interest in laser powder bed fusion (LPBF), only a few cast aluminum alloys are available for this process. This study focuses on improving the LPBF processability of the A6061 alloy, which is challenging due to its wide solidification range, the dendritic columnar grain growth, and consequent solidification cracking. To address these issues, in situ-synthesized grain refiners can be used to induce equiaxial grain growth and prevent crack formation. A6061 RAM2 powder—a mixture of A6061, Ti, and B4C—was characterized and processed using a low-power LPBF machine to create an in situ particle-reinforced metal matrix composite. Parameter optimization was performed to evaluate the effect of their variation on the printability of the alloy. Microstructural characterization of the samples revealed that the complete reaction and the synthesis of the ceramic reinforcement did not occur. However, TiAl3 was synthesized during the process and promoted a partial grain refinement, leading to the formation of equiaxial grains and preventing the formation of solidification cracks. The tensile tests carried out on the optimized samples exhibit superior mechanical properties compared to those of A6061 processed through LPBF.