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Titanium carbide (TiC) nanoparticles with well‐designed exposed crystal planes perform intriguing prospects for functional and engineering applications. In this study, a simple and controllable in situ synthesis strategy was proposed for the synthesis of TiC nanoparticles with specific morphology. Reaction behaviors suggested that most of TiC nanoparticles were formed by an instantaneous reaction between Al3Ti and Al4C3 in the Al‐rich melt and the resultant morphology was controlled by the discrepant growing rates of (100) and (111) crystal planes. In addition, a growth morphology control model was presented for the prediction and manipulation of the morphology of TiC nanoparticles by the doping of different alloying elements Me (Me = Cu, Mg, Mn, Zn, and Si). According to the morphological observations and density functional theory analyses including the interface energy, charge density differences, and orbital hybridization: Cu, Mg, and Zn atoms could stabilize the Al/TiC(111) interface, whereas Mn and Si atoms promoted the rapid growing and disappearance of the TiC(111) planes in the Al melt. This work provides a feasible way to intelligently design and manipulate TiC nanoparticles with desirable exposed crystal planes, and exhibits a promising prospect for personalized applications. [ABSTRACT FROM AUTHOR]

The in situ nano-TiC x /Al–Zn–Mg–Cu composites with different TiC x content (20, 25 and 30 vol.%) were successfully fabricated by combustion synthesis and hot press consolidation in Al–Ti–C/CNTs systems. The compressive properties and abrasive wear resistance of the composites improved with the increase in the TiC x content. The transformation of carbon source from pure C black to the mixture of C black and CNTs to pure CNTs in Al–Ti–C/CNTs systems leaded to a significant improvement in the compressive properties and wear resistance of the composites as well as a significant decrease in the average size of TiC x particles. The average size of the nano-TiC x particles in 30 vol.% TiC x /Al–Zn–Mg–Cu composite synthesized by the carbon source of CNTs reached 81 nm, moreover, the yield strength ( σ 0.2 ), the ultimate compression strength ( σ UCS ) and the fracture strain ( ɛ f ) of the composite reached 597 MPa, 882 MPa and 21.7%, respectively. [ABSTRACT FROM AUTHOR]

Compared with the Ti–C system, the additions of metals (Fe, Al, and Cu) can increase the lattice parameter and stoichiometry of TiC x by forming metal–Ti intermediate phases (for C/Ti≤0.8). But for C/Ti>0.8, the Fe addition can decrease the lattice parameter and stoichiometry of TiC x by the formation of Fe–C solid solutions due to the hindrance of atom diffusion and the decrease of combustion temperature, while the additions of Al and Cu can increase them by the formation of Al–Ti and Cu–Ti solid solutions due to the dilution of Al and Cu. [ABSTRACT FROM AUTHOR]

It is widely known that the special performances and extensive applications of the nanoscale materials are determined by their as-synthesized structures, especially their growth sizes and morphologies. Hereinto, titanium carbides, which show brilliant comprehensive properties, have attracted considerable attention from researchers. How to give full play to their potentials in the light-weight manufacture, microwave absorption, electromagnetic protection, energy conversion and catalyst areas has been widely studied. In this summarized article, the synthesis methods and mechanisms, corresponding growth morphologies of titanium carbides and their further applications were briefly reviewed and analyzed according to their different morphological dimensions, including one-dimensional nanostructures, two-dimensional nanosheets and three-dimensional nanoparticles. It is believed that through the investigation of the crystal structures, synthesis methods, growth mechanisms, and morphology characterizations of those titanium carbides, new lights could be shed on the regulation and control of the ceramic phase specific morphologies to meet with their excellent properties and applications. In addition, the corresponding development prospects and challenges of titanium carbides with various growth morphologies were also summarized. [ABSTRACT FROM AUTHOR]

Bimodal hybrid in-situ nano-/micro-size TiC/Al composites were prepared with combustion synthesis of Al-Ti-C system and hot press consolidation. Attempt was made to obtain in-situ bimodal-size TiC particle reinforced dense Al matrix composites by using different carbon sources in the reaction process of hot pressing forming. Microstructure showed that the obtained composites exhibited reasonable bimodal-sized TiC distribution in the matrix and low porosity. With the increasing of the carbon nano tube (CNT) content from 0 to 100 wt. %, the average size of the TiC particles decreases and the compressive strength of the composite increase; while the fracture strain increases first and then decreases. The compressive properties of the bimodal-sized TiC/Al composites, especially the bimodal-sized composite synthesized by Al-Ti-C with 50 wt. % CNTs as carbon source, were improved compared with the composites reinforced with single sized TiC. The strengthening mechanism of the in-situ bimodal-sized particle reinforced aluminum matrix composites was revealed. [ABSTRACT FROM AUTHOR]

Nacre-inspired laminated composites have been proven to possess a unique combination of strength and toughness. In this study, we fabricated nacre-mimetic Cu/TiC composites via unidirectional freezing of aqueous TiC slurries containing different amounts of NiO additives, followed by ice sublimation, carbothermal reduction of NiO to Ni during sintering and then gas-pressure infiltration of the Cu melt. The introduction of Ni greatly facilitated the densification of ceramic lamellae and enhanced the interfacial bonding between Cu and TiC. The resultant composites displayed outstanding damage tolerance and anisotropic electrical conductivities. Specifically, for an ∼31 vol% TiC–Cu composite containing 24 wt% Ni in the ceramic lamellae (based on the TiC content), a fracture toughness (K Jc) of 72.5 ± 1.0 MPa·m1/2, work of fracture of 53.4 ± 3.5 kJ/m2, bending strength of 725 ± 11 MPa and longitudinal electrical conductivity of 22.7 MS/m (∼60% of the Cu matrix) were achieved, which were approx. 81%, 536%, 122% and 97% higher than those of the Ni-free composite, respectively. Noticeable toughening was demonstrated to be a consequence of multiple cracking, plastic deformation and uncracked-ligament bridging of the metal layers, as well as crack deflection and blunting. On the other hand, significant strengthening resulted from tailoring the microstructures in the ceramic layers and at the Cu/TiC interface as a result of Ni doping. We believe that the facile strategy adopted herein provides an effective way to solve the problems of wetting and bonding related to metal infiltration and can be readily extended to the preparation of other nacre-inspired metal−ceramic composites. [ABSTRACT FROM AUTHOR]

The size, distribution, and morphology of TiC particle in Fe–Ti–C system have a great influence on the mechanical properties of TiC/Fe composites. In this work, TiC/Fe composites were fabricated in the Fe–Ti–C system with different carbon source and molar ratio by combustion synthesis and hot-pressing method. Morphology and size of ceramic particles, as well as microstructure, interface bonding and mechanical properties of composites were compared. The results showed that the size of TiC particles decreased with increase of Fe content of Fe–Ti–C systems fabricated by the same carbon source, while the particles change from spherical shapes to cubic shapes which can reduce stress concentration between ceramic particles and matrix. Furthermore, TiC/Fe composites fabricated by 5Fe–Ti-carbon blacks (CBs) system exhibited superior yield strength (1523 MPa) compressive strength (2203 MPa) and microhardness (691.5 HV), caused by the high interface bonding strength and lamellar pearlite matrix which can commendably limit the dislocation slip. By comparison, TiC/Fe composites fabricated by 21Fe–Ti-carbon nanotubes (CNTs) system showed higher fracture strain (25.85%) on account of the ferrite matrix with favorable plastic. This work reveals the influence of carbon source and molar ratio of Fe–Ti–C system on TiC/Fe composites, which is helpful to further improve the properties of TiC/Fe composites. [ABSTRACT FROM AUTHOR]

TiC/Al–Cu nanocomposites were fabricated in Al–Ti–C powder systems using carbon black, a mixture of C and carbon nanotubes (C + CNTs), and CNTs via an in-situ method involving combustion synthesis and hot pressing. As the carbon source changed from pure carbon black to the C + CNT mixture and pure CNTs, the size of the TiC nanoparticles decreased gradually. The nanocomposites synthesized based on the C + CNT mixture exhibited the most uniform dispersion of TiC nanoparticles. The 30 vol% TiC/Al–Cu nanocomposite prepared from the C + CNT mixture had the best comprehensive mechanical properties (yield strength (411 MPa), compressive strength (712 MPa), fracture strain (17.2%), hardness (206.8 HV), and wear resistance under the experimental conditions due to having the most uniformly dispersed TiC nanoparticles. The wear mechanism was a combination of plastic deformation, abrasion, and adhesion. This method may be a low-cost and convenient means to control the sizes of in-situ TiC nanoparticles and prepare high-performance TiC/Al–Cu nanocomposites. [ABSTRACT FROM AUTHOR]

Inspired by nacre, we designed biomimetic metal–ceramic composites in which hard and ductile phases were alternately arranged. We first prepared lamellar-structured TiC scaffolds with 25, 30 and 35 vol% solid loadings using a unidirectional freeze casting technique and then measured wetting and infiltration dynamics for a commercial Al cast alloy, ZL107, with the main composition of Al–7Si–5Cu on the porous TiC scaffold using a modified sessile drop method at 850 °C. The wetting was affected by liquid spreading at horizontal surface and infiltration in depth, while the latter played a dominant role in the decrease in contact angle. On the basis of the wetting results, the lamellar ZL107/TiC composites were successfully fabricated by pressure infiltration of the molten ZL107 alloy into porous TiC scaffolds and their mechanical properties were evaluated. The compressive strength and elastic modulus increased while bending strength decreased with increasing TiC content, giving maximum values of 1166 ± 20 MPa, 205 ± 2 GPa and 363 ± 5 MPa, respectively. Formation of (Al m ,Si 1 − m ) 3 Ti, Al 3 Ti and Al 4 C 3 phases in the composites was presumed to deteriorate the toughness of the composites, leading to brittle fracture under loading. [ABSTRACT FROM AUTHOR]

The 50 vol.% (TiC x –TiB 2 )/Cu composites were successfully fabricated by the method of combustion synthesis and hot press consolidation in a Cu–Ti–B 4 C–Zr system. The effect of the content of Zr on the microstructures, hardness, compression properties and abrasive wear behaviors of the composites was investigated. The final products consist of only Cu, TiC x and TiB 2 , and the ceramic particles distribute uniformly in the composites. The sizes of the ceramic particles decrease with Zr addition. With the increasing Zr content, the yield strength, ultimate compression strength and hardness increase, and the fracture strain decreases. The abrasive wear resistance of the composites increases with the increase in the Zr content. [ABSTRACT FROM AUTHOR]

In this study, an innovative method, wherein trace in situ synthesized nano-(TiC+TiB 2) particles are added forged H13 steel, was designed and used to manipulate its microstructure. This refined the grains and laths martensite, increased the retained austenite and carbides, and controlled the carbide segregation. Thus, the strength, plasticity, and toughness of the steel were simultaneously improved. Among the samples, the H13 steel, manipulated by 0.02 wt% nano-(TiC+TiB 2) particles, exhibited the best mechanical properties. Its yield strength, tensile strength, elongation, unnotched impact toughness and U-notch impact toughness increased by 11.6%, 7.6%, 14.2%, 35.0% and 33.8%, respectively, and reached 1142 MPa, 1426 MPa, 16.9%, 449.3 J/cm2, and 41.39 J/cm2, respectively. The main strengthening mechanisms were grain boundary strengthening, dislocation strengthening and dispersion strengthening. This study provides a new method for the bonding between ceramic nanoparticles and steel and provides a novel idea for the development of high-performance and low-cost steel. • The nano-(TiC+TiB 2) particles (NPs) are beneficial to nucleation of γ-Fe/α-Fe. • The trace nano-(TiC+TiB 2) particles inhibited carbide segregation of H13 steel. • More and fine carbides and austenite are yielded by adding trace nanoparticles. • The H13 steel with high comprehensive properties is prepared by adding trace NPs. [ABSTRACT FROM AUTHOR]

Abstract: Many experimental and theoretical studies indicated that the decrease of the size of the reinforcing particles can lead to substantial improvements in the mechanical performance of the composites. However, the investigations on the addition of the nano particles into conventional metal materials are still rare, especially the nano-TiC p into the Al–Cu alloys. In this study, the Ni coated nano-TiC p reinforced Al–Cu matrix composites were successfully fabricated by a casting route. It was found that the nano-TiC p was in the α-Al grains. The α-Al dendrites became finer and more developed. Moreover, the θ′ precipitates in the Al–Cu matrix were finer and uniformly distributed. The tensile strength and elongation of the composites increased simultaneously. After T6 heat treatment, compared with the unreinforced Al–Cu alloy, the tensile strength and elongation of the 0.8wt.% nano-sized TiC p /Al–Cu composite increased from 485MPa and 6.6% to 573MPa and 12.4%, respectively. [Copyright &y& Elsevier]

Simultaneously increasing the strength and ductility of hot work die steels is of significant interest for broad applications. The in-situ development of a nano-phase in steels is a promising method for achieving this objective. However, little success has been reported so far. In this study, trace amounts of TiC nanoparticles were successfully introduced into a high-Cr hot work die steel (HHD) through an innovative method using a nano-TiC/Al master alloy. Upon adding 0.02 wt% nano-TiC, an incompletely recrystallized ferrite phase was observed in the HHD containing nano-TiC. Moreover, more globular pearlite was distributed at the ferrite grain boundaries in the HHD with nano-TiC than in the unmodified HHD. The added nano-TiC provided nucleation sites for γ-Fe dendrites and prevented γ-Fe growth during solidification and an austenitizing heat treatment. Furthermore, it noticeably increased the precipitation of more uniform nanoscale chromium carbides and significantly refined the carbides in the HHD during quenching and tempering. Finally, adding nano-TiC simultaneously enhanced the strength and toughness of the HHD. After quenching at 1353 K and tempering at 833 K, the yield strength, tensile strength, tensile strain, and impact toughness of the HHD with nano-TiC were 1330 MPa, 1620 MPa, 14.4 % and 460 J/cm2, respectively, which are all higher than those of the HHD without nano-TiC. • High Cr hot work die steel manipulated by trace nano-sized TiC was fabricated. • Nano-TiC refined grains by promoting γ-Fe nucleation and preventing grain growth. • Nano-TiC prevented recrystallization and promoted Cr 23 C 6 precipitation in the HHD. • Nano-TiC enhanced both the strength and the toughness of the HHD. [ABSTRACT FROM AUTHOR]

A great challenge in producing TiC reinforced metal matrix composites is encountered to directly add TiC particles into molten steel during casting owing to floating of nano-sized TiC on molten steels and agglomeration. As such, this work proposes a novel strategy using pre-distribution in situ nano-sized TiC/Al master alloy to fabricate 45 steel matrix composites reinforced with trace nano-sized TiC particles while without changing the original casting process; this strategy can effectively avoid the aforementioned challenge. The average grain sizes of as-cast and heat-treated 45 steel with 0.018 wt% nano-sized TiC particles remarkably decrease from 14.75 μm to 9.51 μm respectively to 8.77 μm and 5.46 μm respectively, which is attributed to that the nanoparticles provide effective nucleation sites and inhibit grain growth. Furthermore, adding trace nano-sized TiC particles significantly enhances their strength and toughness. The 45 steel matrix composites reinforced with 0.054 wt% nano-sized TiC particles exhibits the best tensile mechanical properties with yield strength of 624 MPa, ultimate strength of 920 MPa, elongation of 23.8% and impact toughness of 50.21 J/cm2, which are 19%, 13%, 10% and 38% respectively higher than the 45 steel. The strengthening and toughening mechanisms of 45 steel by nano-sized TiC are attributed to grain boundary strengthening, work hardening and dispersion strengthening. The strategy proposed in this work may provide a promising method for enhancing steel performances for industrial productions. • Using pre-distribution TiC/Al master alloy to fabricate 45 steel matrix composites. • Microstructure of 45 steels is significantly refined by trace nano-TiC. • 45 steel matrix composites exhibit significantly improved strength and toughness. • New strategy is fabricated for 45 steel matrix composites reinforced with nano-TiC. [ABSTRACT FROM AUTHOR]

• Al matrix composites reinforced with different nanoparticles were investigated. • The corrosion behaviors of the composites were related to the passive film. • TiC p were beneficial for improving the corrosion behavior, but TiB 2p were not. • TiC p reduced the grain boundary phases, improving the corrosion behavior. • TiB 2p at grain boundaries form more corrosion channels, increasing the corrosion rate. Nanosized TiC and TiB 2 particles (TiC p , TiB 2p) can increase the mechanical properties of Al alloys. However, their effects on the corrosion performance of Al alloys are relatively less understood. The corrosion behavior of Al-Mg-Si alloys is improved by adding TiC p and worsened by adding TiB 2p. These changes result from i. TiC p refining the grain structure by acting as nucleants and reducing the number of grain boundary phases and ii. TiB 2p segregating at grain boundaries and accelerating the corrosion. This provides a selection criterion that can be utilized for reinforcement nanoparticles for wrought Al alloys that are applied in corrosive environments. [ABSTRACT FROM AUTHOR]

Freeze casting is a versatile approach for the design of lamellar metal−ceramic composites with unique combination of strength and toughness. However, previous studies mainly focused on ceramic factors such as content and lamellae structure, seldom concerning the effects of metal property and interfacial structures, which, in practice, are key factors in determining the mechanical performances of the composites. In this work, we prepared three kinds of Al/TiC lamellar-interpenetrated composites with different matrix compositions (pure Al, 6061Al (Al−0.4Cu−1.0Mg−0.6Si) and ZL107 (Al–7Si–5Cu)) via freeze casting and pressure infiltration, aiming at clarifying the roles of matrix property and interfacial reaction on the mechanical properties and fracture mechanisms of the composites. The flexural strengths of pure Al/TiC, 6061Al/TiC and ZL107/TiC composites reached 355 ± 10, 415 ± 15 and 459 ± 18 MPa, while the toughness values (characterized by crack-growth toughness) were 81.0 ± 2.0, 57.6 ± 1.2 and 43.4 ± 1.5 MPa m1/2, respectively. The exceptional damage tolerance of these lamellar composites was attributed to multiple toughening mechanisms such as crack deflection, uncracked-ligament bridging of ductile layers and plastic deformation of the metal matrix. However, the presence of Si in the 6061Al and ZL107 alloys weakened the stability of TiC and promoted interfacial reaction, leading to the formation of a certain number of (Al 1-m , Si m) 3 Ti and Al 4 C 3 , which greatly weakened the toughness of the composites. Due to the combined effects of alloy plasticity, lamellar-interpenetrated structure and interfacial reaction, the fracture of the materials changed from a multiple cracking mode in the Al/TiC composite to a single crack propagating mode in the 6061Al/TiC and ZL107/TiC composites. [ABSTRACT FROM AUTHOR]