MPa M0 Research Articles

Mechanical and oxidation behavior of MoSi2-40wt.%Ti5Si3 composites produced by MASHS and SPS

Silicides, known for their exceptional oxidation resistance at high temperatures, are promising materials for advanced applications. Among them, MoSi₂ and Ti₅Si₃ stand out. In this study, a Ti29Mo18Si53 composition was selected to produce a MoSi2-40 wt%Ti5Si3 composite via mechanically activated self-propagating high-temperature synthesis (MASHS). Elemental powders were milled, synthesized in a tubular furnace, and sintered using spark plasma sintering (SPS). The resulting (Ti0.8, Mo0.2)Si2-MoSi2-Ti5Si3 composite maintained stability through sintering, achieving 99 % of its theoretical density, a hardness of 10.9 ± 0.4 GPa, and a fracture toughness of 5.11 MPa m0.5. To evaluate processing effects a second sample, prepared under similar condition but with concurrent synthesis and sintering in the SPS, achieved 97 % density, 7.1 ± 0.5 GPa hardness, and 4.97 MPa m0.5 fracture toughness. Additionally, pure Ti₅Si₃ and MoSi₂ were synthesized separately via MASHS, mixed to form a MoSi₂-40 wt% Ti₅Si₃ composite, and then consolidated by SPS. This composite reached 96 % density, 11 ± 0.6 GPa hardness, and 3.8 MPa m0.5 fracture toughness. Moreover, the (Ti₀.₈Mo₀.₂)Si₂-MoSi₂-Ti₅Si₃ composite demonstrated superior oxidation resistance compared to Ti₅Si₃ and similar to monolithic MoSi₂ up to 1000 °C.

Optimizing damage resistance and structural evolution in CaO-modified Li2O-Al2O3-B2O3-TiO2-P2O5 glass-ceramics

Aluminoborate glass, recognized for its remarkable crack resistance, presents significant potential as a cover material for portable electronic devices. Nevertheless, its relatively low hardness has been a limiting factor. This study synthesized a series of 11 Li2O-30 Al2O3-(55-x) B2O3-2 TiO2-2 P2O5-xCaO (wt%), with x varying from 0 to 10, employing the melt-cast method. The resultant glass-ceramics were produced via heat treatment at 590 °C for 2 h, followed by a systematic examination of their structural and mechanical properties. The investigation demonstrated that an increase in CaO content diminishes crystallization and induces a morphological transition in the crystalline phases from granular and short rod-like structures to lath-like formations, which subsequently impacts the coordination environment of Al and B atoms. With a CaO content of 2 %, the GC2 sample precipitated Li(Al7B4O17) and Li2AlB5O10 phases, achieving a compressive strength (CR) value of 15.0 N, a hardness of 7.51 GPa, and a fracture toughness of 1.50 MPa m0.5. This glass-ceramic exhibited optimal scratch resistance and visible light transmittance exceeding 85 %, underscoring its considerable promise for application as smartphone cover glass due to its impressive overall damage resistance.

Simultaneous effect of microwave sintering and TiO2 addition on sinterability, mechanical properties, and scratch resistance of zirconia toughened alumina ceramics

This paper delves into the transformative impact of varying titanium dioxide (TiO2) content on the sinterability, physical, and mechanical properties, as well as scratch behavior, of zirconia-toughened alumina (ZTA) ceramic composites. By adjusting TiO2 content from 0 wt% to 5 wt% and employing advanced microwave sintering at 1150 °C, the study aims to lower the sintering temperature of ZTA. Microwave sintering, known for its efficiency and rapid processing, enables significant enhancements in material properties at reduced temperatures. Notably, incorporating TiO2 into ZTA yields remarkable improvements in physical and mechanical attributes, with the optimal TiO2 content determined to be 3 wt%. At this concentration, the composite achieves exceptional properties: a relative density of ∼99 %, microhardness of ∼2002 HV, and an indentation fracture toughness of ∼6.13 MPa m0.5. These enhancements represent increases of over 120 % in hardness and 61 % in toughness compared to TiO2-free ZTA. Additionally, the highest scratch resistance is observed at 3 wt% TiO2, evidenced by a minimal scratch depth of ∼7.53 μm. However, exceeding the 3 wt% solubility limit results in the formation of secondary phases, such as tialite (Al2TiO5) and zirconium titanate (ZrTiO4), which degrade the composite's properties. This research underscores the potential of TiO2 doping and microwave sintering to elevate the performance of ZTA ceramics, offering a pathway to superior materials for advanced applications.

Combustion synthesis of the (Ti,Zr)B2-(Zr,Ti)C eutectic composites: Structure formation and properties

The macrokinetic characteristics of combustion of the quaternary Ti-Zr-B-C mixture as well as the mechanism and stages of phase formation for the synthesis products were investigated. The mechanical and thermophysical properties of the hot-pressed boride/carbide ceramics with eutectic composition (Ti,Zr)B2-43%at.(Zr,Ti)C were measured. Preliminary mechanical alloying (MA) of the (Zr + Ti) mixture was shown to yield Ti/Zr granules having a laminar structure and consisting of alternating layers of titanium, zirconium, and (Zr,Ti)ss solid solution. The method used to prepare reaction mixtures and the initial temperature T0 increased within the range of 20–370 °C have virtually no effect on combustion temperature, which is 2260–2400 °C, while higher T0 increases the combustion rate by a factor of 1.5–2. The use of MA Ti/Zr granules reduces the combustion rate as well as the specific heat release amount and the heat release rate. Time-resolved X-ray diffraction data showed that binary carbides (Zr1-xTix)C and diborides (Ti1-yZry)B2 of variable stoichiometry are formed in the combustion wave of the Ti-Zr-B-C reaction mixtures within less than 0.25 s. The carbide and diboride phases are formed simultaneously; the use of MA Ti/Zr granules in the reaction mixtures reduces the content of solid solutions of variable stoichiometry among the reaction products. The ceramics fabricated using a combination of combustion synthesis and hot pressing have a dense and homogeneous structure that consist of bonded grains of the diboride (Ti0.80Zr0.20)B2 and carbide (Zr0.83Ti0.17)C phases having the following properties: density, 5.3 g/cm3; hardness, 22.9 GPa; fracture toughness, 4.7 MPa m0.5; heat capacity, 0.52 J/(g·K); thermal diffusivity, 11.67 mm2/s; and thermal conductivity, 33.28 W/(m·K).

Realizing the outstanding strength-toughness combination of API X65 steel by constructing lamellar grain structure

The development of pipeline steels with exceptional cryogenic toughness is deemed imperative for their applications in various engineering fields. In this work, API X65 steel with lamellar grain (LG) structure is constructed through warm deformation techniques. Comparative analysis with raw API X65 steel revealed notable enhancements in both yield strength (YS) and ultimate strength (UTS), exhibiting increments of 315 MPa and 164 MPa, respectively, while retaining substantial fracture toughness (KIc = 251.14 MPa m0.5). Remarkably, the LG steel exhibits a distinct absence of a ductile-brittle transition behavior over a wide temperature range, maintaining an exceptionally high impact energy from room temperature (RT) to liquid nitrogen temperature (LNT), and the Charpy impact energy exceeding 330 J at LNT, nearly 16 times higher than the raw API X65 steel. This performance can be primarily attributed to the superior plastic deformation capability, coupled with the delamination toughening mechanism. The resultant tortuous path of crack propagation effectively facilitates the absorption of substantial energy, decreases notch tip sensitivity depending on the temperature, stress triaxiality, and strain rate, thereby fostering excellent cryogenic toughness.

Cold-sintered laterite-based geopolymers: Densification, microstructure and micromechanics

The consolidation of natural iron-rich aluminosilicates is enhanced using geopolymerisation, external pressure, and temperature in a ultra-low energy sintering context. Optimized formulations of laterite and Rice Husk Ash (RHA) are used to investigate the effects of the external pressure and temperature on the porosity, phases composition development, micromechanics and microstructure. FT-IR spectroscopy, scanning electron microscopy (SEM 0, Mercury Intrusion Porosimetry (MIP), Transmission Electronic Microscopy (TEM), and the Archimedes Porosimetry method were used to characterize the cold sintered products of geopolymerization of the iron-rich aluminosilicate binders and composites. Results showed that ultra-low energy sintering process allows the reduction of ∼ 99 % of capillary porosity thank to the physico-chemical bonding and the formation of enhanced nanosized ferrisilicates. The indentation modulus > 50 GPa, the hardness modulus of 3,18 GPa and the fracture toughness > 1 MPa m0.5 are in agreement with the compact microstructure, high bulk density (> 2.00 g.cm−3), and low water Absorption. The interlocking of globular units of H-N-(A, Fe)-S with nanosized ferrisilicates leads to high performance ceramics that cannot be achieved with conventional sintering process. Therefore, the cold sintering process demonstrated here is promising for the manufacturing of sustainable matrices using natural iron-rich aluminosilicates.

Constructing coherent/semi-coherent phase boundaries to enhance toughness of superhard cBN-B composite

Harsh synthesized pressure is required in constructing of excellent grain boundary (GB) connection for nano-polycrystalline cubic boron nitride (nPcBN) to yield high hardness and toughness. Therefore, it is urgent to fabricate robust nPcBN composite under relatively mild pressure by developing the hard nonmetal binders to form coherent/semi-coherent phase boundary (cPB, scPB) with cBN. Here, the slight content of nano‑boron was composited with nPcBN to achieve superhard property of 45.2 GPa and high fracture toughness 8.4 MPa‧m0.5 under a relatively mild condition of 5 GPa and 1800 °C. The hardness is comparable with single crystal cBN and the toughness is about three times higher than single crystal cBN. The nano boron connects the nano cBN grains by cPB and scPB, and nano boron filled the triangular space of cBN crystals, which eliminates the defects to prohibit the crack trigger sources and enhances the strength. This work provides a reference and a new strategy on composite engineering in superhard materials with high toughness by relatively mild synthesized pressure.

Effect of densification technology on the microstructure and mechanical properties of high-entropy (Ti, Zr, Hf, Nb, Ta)C ceramic-based cermets

High-entropy ceramic-based cermets represent a new and promising direction in improving the mechanical properties of conventional hardmetals through the formation of complex microstructures during synthesis. This has been systematically studied in two Co-free, high-entropy (Ti,Zr,Hf,Nb,Ta)C ceramic-based cermets using 10 wt% Ni and 10 wt% FeCrAl metallic binders during hot-press and spark plasma sintering. Fully densified microstructures were achieved in the temperature range of 1400–1500 °C, which is below the melting points of the pure Ni and FeCrAl alloy, owing to the liquid-phase assisted sintering. The optimal densification routes resulted in Vickers hardness (HV30) of 16.77 ± 0.72 and 18.32 ± 0.99 GPa, and fracture toughness (KIc_SENB) of 5.31 ± 0.41 and 4.83 ± 0.50 MPa m0.5, respectively for the Ni and FeCrAl bonded cermets. The improved damage tolerance of these cermets compared to the base (Ti,Zr,Hf,Nb,Ta)C high-entropy carbide is related to the reduced grain size and microstructural toughening mechanisms (e.g. crack deflection and bridging).

Making titanium alloys ultrahigh strength and toughness synergy through deformation kinks-mediated hierarchical α-precipitation

Titanium alloys engineered in structural applications achieve ultrahigh strength primarily through precipitation strengthening of secondary α-phase (αs) during aging, while they often experience compromised ductility and toughness due to traditional strength-toughness tradeoff. In this study, we propose a novel strategy to address this conflict by introducing deformation kinks prior to conventional cold rolling (CR) and aging processes. These kinks are produced by cold forging (CF) to create macroscopic lamellar structures in β-grains, which alter strain partitioning during subsequent CR and ultimately tailor αs-precipitation upon aging. As a result, an ultrafine duplex (αe + β)-structure is formed within kink interiors, while hierarchical αs-precipitates are generated in the external β-matrix. This unique microstructure effectively enhances dislocation activity, promotes uniform plastic strain distribution and impedes crack propagation. Consequently, a simple Ti-V binary titanium alloy exhibits exceptional properties with ultrahigh strength ∼1636 MPa, decent ductility ∼5.4 % and appreciable fracture toughness ∼ 36.1 MPa m½. The synergetic properties surpass those obtained through traditional CR and aging processes for the alloy and even outperform numerous multielement engineering titanium alloys reported in literature. Our findings open up a new avenue for overcoming the strength-toughness tradeoff of ultrahigh-strength titanium alloys, and also offer a facile production route towards structural materials for advanced performance.

Study on fracture toughness of quasicrystalline phase in Mg-42Zn-7Y alloy based on indentation technique

The Mg-42Zn-7Y alloy, which contains an icosahedral quasicrystalline phase, was prepared using a conventional solidification process. The fracture toughness of this quasicrystalline phase in the Mg-42Zn-7Y alloy was nondestructively detected using in situ tensile and indentation techniques. The alloy exhibited a tensile strength of 99.17 MPa and an elongation of 3.9%. Microscopic observation and energy spectrum analysis confirmed the high-contrast lamellar structure as the quasicrystalline phase. Ultimately, under cyclic loading during indentation, the fracture toughness of the quasicrystalline phase was determined to be 35.08 MPa m0.5. The findings of the present study provided an effective basis for the determination of the fracture toughness of the quasicrystalline phase.

Multi-component 20La2O3–20TiO2–20Nb2O5-20(Al2O3/ZrO2)-20(ZrO2/Ta2O5) glasses with ultra-high refractive index and mechanical properties inspired by high-entropy design

The highly refractive glasses with excellent mechanical properties (hardness, Young's modulus, and fracture toughness) are highly desired for the lenses used in small optical devices. In this study, a series of five-primary-component 20La2O3–20TiO2–20Nb2O5-20(Al2O3/ZrO2)-20(ZrO2/Ta2O5) (LTNAZ, LTNAT, LTNZT) glasses were designed by using high-entropy strategy and successfully elaborated through a containerless melting-solidification process. The highest refractive index (nd) of the glasses reach up to 2.25. The maximum vickers hardness (HV), Young's modulus (E), and indentation fracture toughness (KIFT) are 10.74 GPa, 157.5 GPa, and 1.23 MPa m0.5 respectively. The glasses exhibit good glass forming ability with kinetic window (ΔT) ranging from 80 to 116 °C. The excellent comprehensive performances of the glasses are attributed to the high electronic polarizability and dissociation energy, as well as the synergistic effect of multiple components in the high-entropy effect. The glasses will be promising host materials for optical applications such as digital product lenses, endoscopes and mini size lasers.

On the role of flat-top beam in pore elimination and fatigue performance of Ti-6Al-4V fabricated by laser powder bed fusion

It's unavoidable to produce defects in the repeated layer-by-layer manufacturing process of laser powder bed fusion (LPBF). This limits the application of LPBF for safety–critical parts. The formation of defects is closely related to the interaction between the laser beam and material in the molten pool. In this paper, beam shaping was used to improve the building quality of LPBF. Process parameter optimization was performed to obtain samples with the fewest defects. Heat treatment was also employed to further improve the mechanical properties. The results showed that the obtained flat-top beam significantly reduced the propensity for keyhole pore formation and enlarged the process windows. In-situ heat treatment induced by high heat input led to the decomposition of martensite and improved the fatigue crack growth (FCG) threshold (∼3.7 MPa m0.5) of the as-built samples. After heat treatment (annealed and solution/aged), the FCG threshold further increased to 5.5/6.3 MPa m0.5, respectively. Reduced defects and high FCG resistance resulted in a fatigue limit above 600 MPa (N = 1e7, R = 0.1), which is comparable to wrought and aged Ti-6Al-4V parts. This study demonstrates the feasibility of improving molten pool stability and reducing defects through beam shaping, providing a new approach to manufacturing high-quality LPBF parts.

Physical properties of radiation dense reactive sintered borides

Reactive Sintered Borides (RSBs) were fabricated to investigate the effects of carbon and chromium content producing a series of samples referred to as Gen 2 RSBs. These RSBs were tested and evaluated for various mechanical (bulk moduli, fracture toughness, nano and micro-hardness) and microstructural properties. It is the first time when the correlation between different RSB phases and mechanical properties are understood in detail, along with the CALPHAD assessment of RSBs. CALPHAD was used to investigate the effect of sintering pressure and composition on melting point and liquid volume at sintering temperature and was critical in understanding of phase differences in Gen 1 and Gen 2 RSBs. Effects of carbon and chromium addition on mechanical and microstructural properties of RSBs were also investigated. Optimal second generation RSBs have fracture toughness of 7–10.1 MPa m0.5 and hardness of 15.9–19.1 GPa. RSBs with relative sintered density >98 % were achieved in this work. Combined X-ray diffraction and EBSD-EDX techniques were used to determine and confirm phase presence in RSBs. This work has demonstrated tractability and reproducibility of RSB materials with suitable mechanical properties for potential applications in spherical tokamaks alongside existing cemented tungsten carbides.

Influence of infill patterns on mechanical properties of 3D printed Al2O3 ceramics via fused filament fabrication

Alumina ceramic components are considered for various applications including aerospace and biomedical owing to its physical and mechanical properties. However, manufacturing complex ceramic shapes with tailored porosity has been an issue via conventional processes. In this study, Al2O3 ceramics were manufactured via Fused filament fabrication (FFF) with different infill patterns i.e., circular, linear, hexagonal and to understand its hardness and indentation fracture toughness. X-ray diffraction peaks corresponded towards corundum supported via elemental mapping indicating the purity of FFF samples. Microstructural analysis indicated presence of micro- and macro-porosities due to binder removal via sintering process. FFF printed samples outperformed their slip-cast counterpart in hardness and fracture toughness irrespective of the infill pattern with linear and hexagonal showing maximum hardness (23.48 ± 0.3 GPa) and indentation fracture toughness (4.49 ± 0.3 MPa m0.5). This research sheds light on the prospects of FFF being utilized to fabricate intricate components with controlled porosity.

Critical evaluation of SEVNP-method to measure fracture toughness of ceramic thin plates

The fracture toughness of ceramic substrates made of alumina, ZTA and silicon nitride was determined using the single edge V-notched plate method. In order to make a statement about the measurement precision, not only 5, as required by the standard, but 30 specimens per material type were tested. In addition, a much more practical and less error-prone holding and testing device for the ceramic plates was used, which is presented in the paper. For all materials, including the comparatively fine-grained ZTA, the material-typical KIc values could be determined. However, the range of variation of the measured values is comparatively high with coefficients of variance up to 7.8 %. It is shown that a standard-compliant test on Al2O3 substrates can exhibit a fluctuation range of 0.5 MPa m0.5 without the material showing any differences. It is important to be aware of this when using the method. Especially for quality assurance, where deviations in the range of a few tenths of MPa∙m0.5 are considered problematic, the method should therefore be regarded as critical. An increase in the number of specimens should be considered, as well as the inclusion of a statement on the precision of the measurement method in the standard.

Exploration into the microstructural, mechanical, and biological characteristics of the functionally graded 3Y-TZP/Ti6Al4V system as a potential material for dental implants

This study investigated the mechanical, microstructural, and biological properties of 3Y-TZP/Ti6Al4V functionally graded material (FGM) fabricated by the spark plasma sintering (SPS) method. For this purpose, 11 layers of 100-x vol% Ti6Al4V/x vol% Yttria stabilized zirconia (YSZ) (x = 0 to 100) were sintered at 1450 °C and a pressure of 30 MPa for 8 min. To investigate the properties of each layer in more detail, 11 batches of 100-x vol% (Ti6Al4V)/x vol% YSZ (x = 0 to 100) composites were sintered separately with the same sintering conditions mentioned for the FGM sample. Phase identification of the FGM sample showed the formation of Ti3O, c-ZrO2, and Zr3O phases as by-products. A schematic model was proposed for the formation of the mentioned phases with the aid of thermodynamic calculations. The formation of these phases was confirmed by microstructural and elemental tests. The results of the relative density of the samples showed that these values were obtained for each layer above 99%. The microhardness of 590 ± 18 Vickers was obtained for Ti6Al4V; by increasing the amount of 3Y-TZP, this value reached 1510 ± 24 Vickers for the YSZ sample. The fracture toughness value for Ti6Al4V was 39.2 ± 2 MPa m0.5, which was significantly reduced to 4.84 ± 1 MPa m0.5 by adding 10 vol% YSZ. After that, with the further increase of YSZ, this value increased slowly. A similar trend was observed for the bending strength of the samples. By increasing 3Y-TZP from 0 to 30 vol%, the bending strength was decreased from 1556 ± 32 to 272 ± 62 MPa. By further increasing the amount of 3Y-TZP from 30 to 100 vol%, an increase in the bending strength was observed in the samples, which reached 1180 ± 71 MPa for the YSZ sample. The FGM sample showed a brittle fracture despite a metal layer, but a higher bending strength (982 ± 44 MPa) was obtained for this structure than the composite samples. The biological results show that increasing YSZ content leads to a decrease in antimicrobial activity. Additionally, all samples demonstrated high biocompatibility based on MTT cytotoxicity tests after 1 and 7 days of culture.

Dy2O3–MgO composite ceramics: Fabrication and properties

An IR-transparent magneto-optical Dy2O3–MgO compositeceramics was fabricated by vacuum hot pressing of glycine-nitrate self-propagating high-temperature synthesized nanopowders. Composites significantly outperform dysprosium sesquioxide ceramics in terms of thermal conductivity and mechanical properties.The HV1 microhardness of the Dy2O3–MgO composite is 9.9 GPa and the fracture toughnessKIC, calculated by the Palmquist method, is 1.7 MPa m½. The thermal conductivity of the composite was measured in the range of 50–300 K and is 10.6 W/(m K) at room temperature. The transmittance of 1.5 mm thick Dy2O3–MgO sample is about 70 % in the wavelength range ∼2.1–2.2 μm and more than 80 % in the range ∼3.6–6.5 μm, which is close to the theoretical value for dysprosium sesquioxide.The value of Verdet constant of Dy2O3–MgO composite ceramics is 7.0 ± 0.3 rad/(T∙m)at 1940 nm.

Effects of alumina addition on electrical properties of alumina-toughened zirconia for application in low- and intermediate-temperature solid oxide fuel cells

One of the priorities in the field of hydrogen energy is the development of intermediate-temperature (IT-SOFCs) and low-temperature solid oxide fuel cells (LT-SOFCs), which are capable of highly efficient operation in the range of 500–800 °C. The currently applied 8-YSZ electrolytes are expected to be replaced by one based on tetragonal zirconia (3Y-TZP), which is characterized not only by high ionic conductivity below 700 °C, but also significantly higher mechanical strength. One of the candidates is alumina-toughened zirconia (ATZ) with extraordinary mechanical properties (flexural strength of up to 1 GPa and outstanding fracture toughness (KIc) in excess of 10 MPa m0.5). A series of composites with a nanometric alumina content of 2.3, 10, and 20 vol% were obtained and investigated to evaluate the effects of aluminum addition on the electrical properties of the materials in relation to their microstructure, chemical and phase composition. Measurements performed by means of electrochemical impedance spectroscopy over the range of 300–650 °C showed that the total electrical conductivity of the obtained ATZ samples decreased slightly with increasing content of alumina inclusions and it was around one-third of an order of magnitude lower than that of the reference 3Y-TZP sinter prepared from the commercially available oxide powder containing 3 mol% of yttrium oxide (TOSOH). This is a consequence of the fact that ATZ sinters exhibited a lower specific conductivity of grain boundaries than 3Y-TZP whilst having comparable electrical conductivity of grain interiors. The total electrical conductivity values determined for the ATZ sinters at 700 and 800 °C are approximately the same as the electrical conductivity of 3Y-TZP, and they can therefore be considered a viable alternative to 8-YSZ electrolytes in applications such as IT-SOFCs or LT-SOFCs.

2Y-TZP ceramics with high strength and toughness by optimizing the microstructure

Low-yttria doped zirconia polycrystals (Y-TZP) have recently emerged as new fine-grained zirconia ceramics exhibiting a promising combination of high fracture toughness and strength. In this investigation, we optimized the strength and fracture toughness of 2Y-TZP ceramics prepared by gelcasting and pressureless sintering. The 2Y-TZP ceramics with optimized processing reached a mean biaxial strength of 1070MPa, similar to the strength obtained for the standard 3Y-TZP ceramics. However, a higher transformability of tetragonal grains in 2Y-TZP ceramics resulted in a stronger transformation toughening effect compared with 3Y-TZP ceramics. The fracture toughness obtained for 2Y-TZP exceeded that of 3Y-TZP (7.7 vs. 5.2MPa m0.5). The differences in the microstructure and toughening mechanism between 2Y-TZP and 3Y-TZP were described, and the potential benefits of the 2Y-TZP were discussed.

UV-Curing Assisted Direct Ink Writing of Dense, Crack-Free, and High-Performance Zirconia-Based Composites With Aligned Alumina Platelets.

Additive manufacturing (AM) of high-performance structural ceramic components with comparative strength and toughness as conventionally manufactured ceramics remains challenging. Here, a UV-curing approach is integrated in direct ink writing (DIW), taking advantage from DIW to enable an easy use of high solid-loading pastes and multi-layered materials with compositional changes; while, avoiding drying problems. UV-curable opaque zirconia-based slurries with a solid loading of 51 vol% are developed to fabricate dense and crack-free alumina-toughened zirconia (ATZ) containing 3 wt% alumina platelets. Importantly, a non-reactive diluent is added to relieve polymerization-induced internal stresses, avoid subsequent warping and cracking, and facilitate the de-binding. For the first time, UV-curing assisted DIW-printed ceramic after sintering reveals even better mechanical properties than that processed by a conventional pressing. This is attributed to the aligned alumina platelets, enhancing crack deflection and improving the fracture toughness from 6.8 ± 0.3MPa m0.5 (compacted) to 7.4 ± 0.3MPa m0.5 (DIW). The four-point bending strength of the DIW ATZ (1009 ± 93MPa) is also higher than that of the conventionally manufactured equivalent (861 ± 68MPa). Besides homogeneous ceramic, laminate structures are demonstrated. This work provides a valuable hybrid approach to additively manufacture tough and strong ceramic components.