High-performance Metal Matrix Composites Research Articles

Multi-functional amorphous/crystalline interfaces rendering strong-and-ductile nano-metallic-glass/aluminum composite

Metal matrix composites (MMCs) are the materials-of-choice for a large range of important applications under harsh service conditions. However, owing to the high phase contrast between the matrix and the reinforcements, the strength-ductility conflict of MMCs is still outstanding. Here we fabricated a novel aluminum (Al) matrix composite reinforced by deformable, cobalt-zirconium-boron (CoZrB) metallic glass nanoparticles. The amorphous CoZrB/Al composite with only 2.0 vol.% particle reinforcements possessed a uniaxial tensile strength of 387.0 ± 1.2 MPa, showing over 80 % improvement over the unreinforced pure Al matrix at a similar uniform elongation. The strength-ductility synergy of the composite was also significantly superior to that of the composite reinforced by fully crystallized nanoparticles. These findings were rationalized by the unique multi-functionality of the amorphous particle/matrix interfaces, which effectively transferred the load from the matrix to the particles, coordinated the co-deformation of the nanoparticles and the matrix, and imparted a transgranular fracture mode in the composite with extensive matrix plastic deformation. The methodology developed in this study was shown to be generally effective for other matrix and metallic glass nanoparticle compositions, and our work may shed new light on the development of high-performance metal matrix composites for advanced structural applications.

Synergistic effect of niobium carbide and titanium nanoparticles on the mechanical and microstructural properties of Al-Zn-Mg-Cu alloy hybrid composites

In this study, an Al-Zn-Mg-Cu alloy matrix serves as the matrix material, with Niobium Carbide (NbC) and Titanium (Ti) nanoparticles acting as reinforcements to enhance composite strength. Incorporating nano-structured reinforcements significantly enhance both strength and toughness, surpassing micro-sized counterparts. To prevent nanoparticle agglomeration during manufacturing, we employ vigorous stirring via the stir casting technique to ensure uniform dispersion within the composite matrix. SEM analysis confirms uniform dispersion of NbC and Ti nanoparticles within the matrix. Experimentally, the composite exhibits exceptional tensile strength, with sample B achieving the highest load of 5500 N, correlated with an optimal NbC percentage of 5 wt% and Ti percentage of 2 wt%. However, increasing NbC percentage from 5 wt% to 10 wt% results in decreased ductility and tensile strength for composite C. Similar trends are observed in bending strength, with composite B exhibiting the highest load at 9023.8 N, surpassing samples C and D. Microhardness results demonstrate an increase with NbC content, peaking at 230 HV, but declining to 185 HV with reduced NbC and Ti concentrations. Charpy impact tests reveal a consistent rise in impact energy from samples B to D, attributed to the escalating proportion of NbC relative to Ti. Overall, meticulous material selection and processing optimization are essential for developing high-performance metal matrix composites with enhanced mechanical properties.

The strengthening mechanism of mechanical and tribological properties of TiC-reinforced 316L matrix composites fabricated by selective laser melting

Selective laser melting (SLM) has been proved to be a promising additive manufacturing technique to fabricate high-performance metal matrix composites (MMCs) with unique microstructures. In this study, TiC-reinforced 316 L MMCs were successfully prepared by SLM. The effects of TiC addition on the microstructure evolution, mechanical properties and tribological behavior were systematically investigated to study the strengthening mechanism. The TiC/316 L MMCs fabricated by SLM exhibited a high relative density of over 99.6% and were close to full density. The TiC particles are effectively bonded with the 316 L matrix, serving as a means of dispersion strengthening. In addition, the grains were significantly refined, and the dislocation density was greatly enhanced with the addition of TiC particles, which reinforce the strength of the material. Tensile tests show that the tensile strength of TiC/316 L MMCs increased by 49.9% from 707 to 1060 MPa and yield strength increased by 44.2% from 543 to 783 MPa with 4 wt% TiC. Besides, the tribological behavior of TiC/316 L MMCs was much superior to the pure 316 L. The findings provide a new perspective on ceramic particles reinforced stainless steel MMCs with tailored microstructure and excellence performance.

Microstructural evolution, mechanical properties and tribological behavior of SiC reinforced 316L matrix composites fabricated by additive manufacturing

Selective laser melting (SLM) has been proved to be a promising additive manufacturing technique for production of high-performance metal matrix composites (MMCs) with unique microstructures. In this study, the SiC- reinforced 316L MMCs were prepared by SLM and the effects of SiC addition on the densification, microstructure evolution, mechanical properties and tribological behavior were systematically investigated. The SiC/316L MMCs fabricated by SLM were close to full density with high relative density over than 99.7%. The grains were significantly refined, and dislocation density was greatly enhanced with the addition of SiC particles. Tensile tests show that tensile strength of the specimens increased by 81.8% from 707 to 1285 MPa and yield strength increased by 72.7% from 543 to 938 MPa with the addition of SiC. In addition, the tribological behavior of MMCs with SiC addition are much superior to the pure 316L. The underlying strengthening mechanisms are discussed. The findings provide a new perspective on ceramic particles reinforced stainless steel MMCs with unique microstructure and excellence performance.

Microstructure and Mechanical Properties of Cu-CoatedCarbon-Nanotubes-Reinforced Aluminum Matrix Composites Fabricated by Ultrasonic-Assisted Casting

Carbon nanotubes (CNTs) are considered ideal nanoscale reinforcement for the development of high-performance metal matrix composites due to their unique structure and excellent mechanical properties. However, CNTs are easy to agglomerate and have poor wettability with the aluminum matrix, resulting in unsatisfactory effects when added to the aluminum melt. In this study, Cu-coated carbon nanotubes (Cu@CNTs)-reinforced aluminum matrix composites were fabricated by high-energy ultrasonic-assisted casting. Moreover, the effects of different Cu@CNTs content on the microstructure and mechanical properties of aluminum matrix composites were explored. Meanwhile, Fluent 19.0 software was used to further explore the function of ultrasonic vibration in the melt. The results demonstrated that the mechanical properties of composite with 1.2 wt% Cu@CNTs are optimal. Compared with the matrix, the composite with 1.2 wt% Cu@CNTs displayed a 39.3% increase in yield strength, 53.5% increase in ultimate tensile strength, and 5.7% increase in elongation. The simulation results showed that the uniform dispersion of Cu@CNTs and grain refinement can be attributed to the acoustic streaming effect and cavitation effect of high-energy ultrasound. The improvement of the properties of the composites can be attributed to the grain refinement and the load-bearing effect of CNTs.

The Impact of Friction Stir Process on Mechanical Properties of AA6082 Enhanced by Titanium Aluminum Carbide Ti3AlC2

This study investigates the effects of Friction Stir Processing (FSP) on the mechanical properties and microstructural refinement of aluminum alloy AA6082 and its composite reinforced with Titanium Aluminum Carbide (𝑇𝑖3𝐴𝑙𝐶2). The primary aim was to determine the extent to which FSP can enhance the compression strength and modify the microstructure of the base AA6082 and the AA6082/𝑇𝑖3𝐴𝑙𝐶2 metal matrix composite. Through a series of FSP treatments, we observed a microstructural refinement of 26% in the composite material. Concurrently, the compression strength of the materials processed by FSP demonstrated a significant increase of 16.3%. These results suggest that FSP is an effective method for enhancing the mechanical properties of AA6082, with implications for the material's application in industries where the strength-to-weight ratio is critical. This paper provides a detailed analysis of the microstructural transformation mechanisms and the corresponding enhancement in mechanical properties, offering insights into the potential of FSP in developing high-performance metal matrix composites.

Dispersion of reinforcing micro-particles in the laser welding of metal matrix composites: High-fidelity modeling with experimental characterization

Understanding the interaction mechanism between keyhole, solid phase (ceramic particles), and liquid phase (metal matrix) will offer key insights into laser welding/additive preparation of high-performance metal matrix composites. The laminar SiC particle–reinforced Al matrix composite, which is extensively used in aviation structural parts, is utilized as the experimental model. The effect of the keyhole mode on the migration behavior of SiC particles in the weld pool was revealed by simulating the multiphysical thermal fluid flow during the laser-welding process. The simulation results revealed that the flow of the molten pool and the keyhole mode have significant effects on the migration behavior of particles. The variation of keyhole mode leads to considerable changes in molten pool dynamics and corresponding SiC particle distributions in the molten pool. The observed selective distribution of SiC particles is due to the flow characteristics of the molten pool. In addition, results showed that the keyhole mode can maximize the uniform distribution of SiC particles in the melt pool, thereby addressing the nonuniformity problem of SiC particles. This work is a fundamental advancement in the modeling of laser-welded SiC particle–reinforced Al matrix composites and provides unprecedented details on the effects of keyhole patterns on weld pool dynamics. This work can further offer practical guidance for “temperature field–regulating reaction behavior” and “velocity field–regulating distribution behavior.”

Improving carbon nanotube dispersion in aluminum matrix composite powders by a repeating-deformation ball milling process

During high energy ball milling, nano-reinforcements can be gradually dispersed in metal powders with the severe plastic deformation of metal powder particles. However, prolonged deformation soon results in intrinsic cold-welding of metal powder particles, leading to unpleasant dispersion effect and great difficulty in dispersing high contents nano-reinforcements. In this study, a repeating deformation ball milling (RDBM) process was proposed to deal with the excessive cold-welding of aluminum (Al) powders to achieve homogeneously dispersed carbon nanotubes (CNTs). Results showed that the plastic deformation of cold-welded Al powders was re-activated by re-adding the process control agent of stearic acid in the CNTs/Al composite powder. Compared with the cold-welded powder, the composite powder fabricated by RDBM had improved CNT dispersion and finer matrix grains down to nanoscale, leading to noticeably enhanced elastic modulus and hardness. Microstructures during RDBM were examined in detail to understand the dispersion mechanism of CNTs. The reported RDBM strategy in this study can be a guidance for optimizing high energy ball milling process to acquire homogeneous dispersion of high contents of nano-reinforcements and high-performance metal matrix composites.

Microstructure and properties of FeCoNiCrMn and Al2O3 hybrid particle-reinforced aluminum matrix composites fabricated by microwave sintering

In this paper, multiscale Al2O3 micro/nanoparticles (0–14 wt%) mixed with FeCoNiCrMn high-entropy alloy (HEA) particles (15 wt%) were used as reinforcements to prepare dual-phase-reinforced aluminum matrix composites (AMCs) through microwave sintering. The strengthening effects of doping different weight fractions of Al2O3 micro/nanoparticles on the microstructure, mechanical properties, and strengthening mechanisms of the mixed-phase particle-reinforced AMCs were investigated. The performance after 11 wt% Al2O3+HEA microparticles was similar to that obtained by adding 2 wt% and 5 wt% Al2O3+HEA nanoparticles. The hardness, yield strength, and compressive strength of the 2 wt% nano-Al2O3 composite were 109.7 HV, 286.5 MPa, and 506.7 MPa, respectively, which were 70.9%, 98.5%, and 94.7% higher than those of the single HEA-reinforced sample. In terms of the strengthening and toughening mechanisms, Orowan strengthening, dislocation strengthening, and thermal mismatch strengthening were the main strengthening mechanisms of particles species mixed in the metal matrix composites. Hall-Petch strengthening and load-transfer effects were mainly attributed to the cross-scale mixing of particles. The hybrid particles of HEA and Al2O3 synergistically delayed interfacial crack propagation. This study provides a new preparation method for high-performance metal matrix composites.

High strength and high electrical conductivity Cu composites reinforced by SiO2 aerogel particles

For high-performance metal matrix composites, maintaining the uniform distribution of the small-sized reinforcement phase in the matrix is the key to fully exploiting the advantages of the reinforcement phase, but it is also a technical difficulty. In this work, a new type of reinforcement phase—SiO2 aerogel particles, was selected to be added into the Cu matrix. Utilizing the characteristics of easy dispersion of the nanoporous structure in its original state and then densification under a high temperature load, its uniform distribution in the Cu matrix can be achieved by a simple powder metallurgy method. The composites have excellent electrical conductivity and high strength, which is mainly attributed to the unique distribution of silica aerogel particles: larger particles are distributed on the grain boundary, and smaller particles are distributed in the grain, which can greatly refine the grain. Quantifying the contribution of various strengthening mechanisms to yield strength increases, the results revealed that the grain refinement strengthening mechanism plays a leading role. Moreover, this work provides a new strategy for preparing high-performance copper matrix composites.

Additive manufacturing SiC-reinforced maraging steel: Parameter optimisation, microstructure and properties

The unique deposition manner of additive manufacturing (AM) allows the near-net-shaping of components with multiple materials configurations and complex geometries, which sheds light on the process of high-performance metal matrix composites (MMCs). This work explores laser powder bed fusion (LPBF) AM of SiC-reinforced maraging steel MMCs to consolidate the merits of both ceramics and metal matrix for improving overall properties. The laser processing parameters were systematically optimised based on the density, roughness and hardness of the deposited samples. The effects of SiC content on the microstructures, mechanical properties, tribological performance, and wear resistance are elucidated. SiC particles are refined with uniform distribution in the metal matrix after laser processing. The highest tensile strength reaches 1611 ​MPa together with an elongation of about 10.1% with 3 ​vol% SiC addition. The tribological performance of MMCs is investigated by studying the coefficient of friction (COF), wear rate, and worn morphology. The COF has been slightly reduced with the SiC addition, and the wear rate of MS reduced from 3.25 ​× ​10 −5 to 1.72 ​× ​10 −5 mm 3 /Nm with the 12 ​vol% SiC addition. The underlying wear mechanisms are also investigated. Besides, the corrosion behaviour of MMCs is also investigated; the addition of SiC (≥6 ​vol%) has improved the corrosion properties of the matrix.

Effects of the CuO additive nanoparticles on the internal strain homogenization and microstructure evolution in Ag-SnO2 composites

Stress concentration caused by reinforcements has very unfavorable effects on the metal matrix composites, which will inevitably induce localized strains and crack initiation. In this paper, an effective approach is presented to relieve stress concentrations near the reinforcements in metallic composites. The Ag-SnO2 contact materials with CuO additive are prepared by electroless plating combined with powder metallurgy method. The CuO nanoparticles in-situ formed on the SnO2 reinforcements are adopted to relieve local stress concentrations near the Ag/SnO2 interfaces and promote strain homogenization. The mechanical properties, deformation characteristics and microstructure evolution of the Ag-SnO2 composites without and with CuO additive are systematically studied by experiments and numerical simulations. The results show that the CuO nanoparticles formed on the surfaces of the SnO2 reinforcements dramatically improve the mechanical properties of the Ag-SnO2 composites, particularly the plasticity at a higher loading rate. The ultimate strength of the Ag-SnO2(CuO) tensile specimens is increased from 104 to 127 MPa, and the uniform elongation is increased by 83% compared with that without CuO. It is demonstrated that the dislocation tangle around the CuO nanoparticles effectively relieves the adverse effect of the stress concentration near the SnO2 and results in the strain homogenization in the Ag matrix. Furthermore, the damage evolution of the Ag-SnO2 composites without and with CuO nanoparticles is investigated by the Gurson-Tvergaard-Needleman (GTN) models under uniaxial tension. The error range of the simulated stress-strain curves is lower than 4%. The nucleation and growth of voids at the interfaces of the Ag-SnO2 composites are numerically simulated and discussed. This study provides a fundamental basis for developing novel high-performance metal matrix composites.

Borophene reinforcing copper matrix composites: Preparation and mechanical properties

The excellent mechanical properties that combine strength, flexibility and toughness make borophene a highlighted material system for innovative applications of nanoelectronic devices and promising for reinforcing metal matrix composites. However, the experiments have not been reported so far due to the difficulty of macroscale preparation of borophene sheets. Recently, large-scale, free-standing, ultrastable hydrogenated borophene sheets have been synthesized in our group using an in-situ multi-step thermal decomposition method of sodium borohydride. Here, borophene reinforcing copper matrix composites were prepared by in-situ thermal decomposition of sodium borohydride powder in hydrogen rich environment. The corresponding bulk three-dimensional borophene sheets network/copper composites were prepared by spark plasma sintering. The structure of borophene in the samples before and after sintering is well consistent with that of triangular borophene. The mechanical properties of the composites are significantly improved by the introduction of borophene. The yield strength and ultimate tensile strength of the composites are close to the reported highest values of graphene in copper matrix and far beyond those of boron nitride in copper matrix. The change of fracture mode from ductile fracture to brittle fracture is ascribed to the stronger interfacial affinity between borophene and copper compared with that between graphene and copper. This study paves the way for the practical application of borophene in high-performance metal matrix composites.

Fabrication and performance of SiC-reinforced Cu: Role of the aspect ratio of the SiC reinforcement phase

In this study, SiC particle (SICP)- and SiC whisker (SICW)-reinforced Cu composites were prepared by pulse intermittent deposition and subsequent spark plasma sintering (SPS). After electrodeposition, the formation of Cu-coated SICP and SICW core–shell structures solved the problem of agglomeration of the second phase during the subsequent sintering. In addition, the wetting layer of Cu increased the bonding strength of the interface between Cu and the second phase. The strength of SICP-reinforced Cu was higher than that of pure Cu at the expense of elongation and thermal conductivity. Compared to SICP-reinforced Cu, SICW-reinforced Cu exhibits significantly higher strength, plasticity and thermal conductivity. The externally applied load was transferred from a soft Cu matrix to stiff SICWs, thus increasing the yield strength of the composites. Furthermore, bridge cracks, crack deflection, and whisker pull-out mechanisms improved the elongation of the composite. This work reveals the relevance of the strengthening mechanism and the aspect ratio of the reinforced phase systematically and provides an advanced pathway to fabricate high-performance metal–matrix composites by designing discontinuous second phases with tailored aspect ratios.

Mechanical Properties of Al7075 Hybrid Metal Matrix Composites as a functionality of SiO2 % in the RHA

Hybrid metal matrix composites are wide in applications due to their improved mechanical properties. Where the optimum selection of reinforcements becomes necessary for determining the feasibility of producing high-performance metal matrix composites with low cost. Consequently, in Al7075, a hybrid metal matrix composite (MMC) with boron carbide and rice husk ash was reinforced. This current research determines the effect of heating temperature on the production of rice husk ash, and it was discovered that the temperature effect improved the SiO2 content of the rice husk ash (RHA). In addition, the deposition method of RHA into the AI7075 substrate was used as a variable, and the effects on the microhardness and tensile properties of the resultant were investigated. The introduced hybrid MMC was reinforced with 2% boron carbide particles and 5%, 10%, and 15% RHA respectively using the stir casting technique. Hence, mechanical performances like tensile strength, compressive strength, impact tests, and hardness tests were performed efficiently.

Inhibiting the interfacial reaction between few-layered graphene and titanium via SiC nanoparticle decoration

The high reaction tendency between graphene and titanium (Ti) matrix during fabrication of graphene/Ti composites aggravates the structural integrity of graphene and limits its outstanding strengthening potential. In order to solve this problem, in this study, few-layered graphene (FLG) decorated with SiC nanoparticles (SiCp@FLG) was synthesized to reinforce Ti-6Al-4V (Ti64) alloy via a powder metallurgy route. Microstructure and Vickers hardness of the developed SiCp@FLG/Ti64 composites were studied systematically. Results showed that the SiCp decoration changed the morphology of FLG/Ti interface from continuous TiC reaction layer to discontinuous TiC nanoparticles during hot-press sintering. This discontinuous interface not only kept the integrity of FLG by suppressing its reaction with Ti matrix but also led to direct bonding between FLG and Ti. This designing strategy of protecting the reinforcement by secondary particle decoration can be potentially applied to the development of high-performance metal matrix composites.

Effect of annealing treatment on microstructure and mechanical properties of cold sprayed TiB2/AlSi10Mg composites

Cold spray allows for fabricating metal matrix composites or repairing damaged components in a scalable way with a high deposition rate. Nevertheless, the poorly bonded interfaces (both metallic splats/splats and metallic splats/reinforcements) and pores in the composite deposit result in undesirable mechanical performance, which limits its applications for load-bearing components. In this study, a special designed composite powder reinforced with in-situ TiB2 particles was used as the feedstock to produce TiB2/AlSi10Mg composite components by cold spray additive manufacturing. Following this, the effect of post-annealing treatment on interfaces and micro-pores healing, microstructure evolution, and mechanical properties of the cold sprayed TiB2/AlSi10Mg composites was investigated in terms of X-ray diffraction, electron backscatter diffraction, transmission electron microscopy, and tensile test. The cold sprayed composite exhibited a bimodal structure with ultrafine grains formed at the inter-splat boundaries due to dynamic recrystallization induced by intensive plastic deformation of the particles. In addition to the uniformly dispersed TiB2 nanoparticles, some aggregated clusters remained embedded in the Al matrix. Tensile tests revealed that the as-sprayed deposits possessed very high tensile strength but almost no toughness due to the poorly bonded inter-splats and enhanced work hardening effect. Significant improvement in ductility was achieved in the annealed samples through improvement of metallurgical bonding between the deformed splats, release of residual stress, and static recrystallization. Interestingly, when the annealing temperature was increased up to 500 °C, both the pure AlSi10Mg and TiB2/AlSi10Mg composite samples fractured at a very early stage due to the presence of large pores (>20 µm) which may originate from the moisture of initial powders. The in-situ formed TiB2 nanoparticles play an important role in strengthening the Al matrix, meanwhile, maintaining a good ductility due to the robust interface bonding. This study demonstrates the potential of using a gas-atomized composite powder to produce high-performance metal matrix composites by cold spray additive manufacturing followed by annealing treatment.

Effect of Metal Powder Characteristics on Structural Defects of Graphene Nanosheets in Metal Composite Powders Dispersed by Ball Milling

Ball milling (BM) is the prime method to disperse graphene into metal powders; however, it inevitably introduces structural defects to graphene. The balance between dispersion quality and structural damage of graphene during BM is a significant issue for fabricating graphene/metal composite powders. In this study two metal powder characteristics, namely type and size, were investigated to understand the effect of the BM process on graphene structure in graphene/metal composite powders. Graphene nanosheets (GNSs) were added into commercial Ti-6Al-4V and pure Al powders with different diameters by three kinds of BM processes with distinct energy levels. According to the microstructure and Raman spectra, the results suggested that metal particle size had a minor influence in low-energy BM, while it played an important role in high-energy BM (HEBM). The structural defects of GNS crystals increase with increasing BM energy. However, increasing energy in BM has limited damage as the discrepancy in particle size is quite large. Furthermore, Al powders with lower hardness tend to deform with lower BM effect, which will cause less damage to GNSs compared to that in the harder Ti powder. Those findings may have implications for the development of high-performance metal matrix composites reinforced with nanocarbon materials.

Microstructure, tensile properties and deformation behaviors of aluminium metal matrix composites co-reinforced by ex-situ carbon nanotubes and in-situ alumina nanoparticles

In this study, the origin of the high tensile ductility (>10% strain to fracture) of a new class of high-strength (yield strength >500 MPa) aluminium (Al) metal matrix composites (Al MMCs) co-reinforced by ex-situ carbon nanotubes (CNTs) and in-situ γ−Al2O3 nanoparticles was investigated. The microstructures of these unique Al MMCs prior to and post tensile testing were characterized in detail using high resolution transmission electron microscopy, in order to understand their response to tensile deformation. The pathways to the in-situ formation of γ−Al2O3 nanoparticles were identified and attributed to the high energy ball milling process, and the subsequent spark plasma sintering, which converted the amorphous Al-oxide into γ−Al2O3 nanoparticles. The in-situ γ−Al2O3 nanoparticles and Al matrix exhibited a semi-coherent interface, which led to a markedly increased dislocation density in the matrix around the nanoparticles during tensile deformation. These dislocations were precursors to microvoid formation and consequent dimples on further deformation. The co-operation of CNTs and γ−Al2O3 nanoparticles resulted in a long strain-softening stage and therefore excellent tensile ductility. The results suggested that the exploitation of hybrid reinforcement by ex-situ CNTs and in-situ nanoparticles can enable the fabrication of high-performance metal matrix composites.

Synergistic strengthening effect of carbon nanotubes (CNTs) and titanium diboride (TiB2) microparticles on mechanical properties of copper matrix composites

Synergistic strengthening is increasingly explored for developing high-performance metal matrix composites. In the present work, copper matrix composites reinforced with carbon nanotubes (CNTs) and TiB2 microparticles were fabricated via electroless deposition, powder metallurgy, hot extrusion, and water quenching. The synergistic strengthening effect of the nano-and micro-reinforcements was elaborated and analyzed based on experimental investigation and theoretical calculation. (1CNT-4TiB2)/Cu composite exhibited a better combination of the tensile strength of 375MPa with elongation of 32.4% than other composites, representing 86.3%, 71.5%, and 22.8% strength increment in comparison with pure Cu, 4TiB2/Cu composite, and 1CNT/Cu composite, respectively. The strengthening efficiency of CNTs in (1CNT-4TiB2)/Cu composite is markedly higher than that in 1CNT/Cu composite (126.7 and 82.3, respectively), confirming the synergistic strengthening effect in enhancing the mechanical properties. Quantitative analysis and experimental characterization indicated that the thermal mismatch and load transfer mechanism of CNTs were the main factors contributing to the tensile strength enhancement of the composite. The synergistic strengthening effect was attributed to that TiB2 microparticles improved the homogeneous dispersion of CNTs, promoting the proportion of thermal mismatch and load transfer mechanisms. The present work may provide a new sight into improving the synergistic strengthening effect in metal matrix composites.