TiB2 Phases Research Articles

Fabrication of (TixZr1−x)B2-(ZrxTi1−x)N composites by reactive spark plasma sintering of ZrB2-TiN

In this study, microstructural and mechanical properties of (ZrxTi1−x)N-(TixZr1−x)B2 composite fabricated by reactive spark plasma sintering (SPS) of ZrB2 and TiN was investigated. ZrB2 and TiN starting materials with equimolar ratio were sintered at 2000 °C for 8 min under a pressure of 30 MPa. An expansion (about 4%) was observed during the sintering process of the composite in the temperature range between 1290 °C and 1625 °C, which was attributed to the reaction of the starting materials. XRD pattern of the fabricated composite revealed the formation of TiB2 and ZrN phases after the sintering process. It was found that (Ti0.91Zr0.09)B2 and (Zr0.92Ti0.08)N phases are formed after sintering. High values of Vickers microhardness (28 ± 0.2 GPa), flexural strength (706 ± 51 MPa) and fracture toughness (8.49 ± 0.92 MPa m1/2) were achieved for this composite. Fracture of the (ZrxTi1−x)N and (TixZr1−x)B2 phases and crack path deflection mechanisms was founded as dominant toughening mechanisms in this composite.

Effect of Aging Treatment on Microstructure and Wear Properties of CoCrFeNiTiNbB1.25 High Entropy Alloys Coatings by Laser Cladding

ABSTRACTLaser cladding CoCrFeNiTiNbB1.25 high entropy alloys (HEAs) coatings on H13 steel was fabricated. The effect of aging treatment temperature on microstructure and wear resistance of the HEAS coatings was investigated. Results showed the phases of the HEAs coatings were not changed as the aging treatment increased, the volume fraction of TiB phase was firstly increased, then reduced. The diffraction peak of fcc phase was firstly shifted to the right, and then shifted to the left. The HEAs coatings consisted of typical dendrite, interdendritic eutectic and dispersed intermetallic compound after aging treatment, and the dendrite obviously was coarsened after aging treatment at 850 °C. Compared with HEAs coatings before aging treatment, the microhardness of the HEAs coatings was firstly increased as the aging treatment temperature increased, then decreased, and the mass loss was opposite. The microhardness and mass loss was decreased by 4.3% and 11.9%, respectively for the aging treatment at 750 °C. The wear mechanism of the HEAs coatings before aging treatment was the abrasive wear, and was the abrasive wear and adhesive wear after aging treatment.

Investigation of microstructure and mechanical properties of novel MgLiAlZnY–TiB alloys based on secondary phase prediction by first principle

In the work, secondary phases in MgLiAlZnY–TiB alloys (α, α+β, β) were predicted by first principle, and microstructural evolution and mechanical properties of the alloys at different AlTiB contents (0, 0.1, 0.5, 1.0 wt %) were also investigated. The result of prediction showed that Al2Y, AlLi, TiB2 and Al3Ti phases are likely to emerge, and anisotropies of AlLi and Al3Ti are stronger than that of Al2Y and TiB2. In addition, bonding of AlLi and Al3Ti mainly consists of ionic and metallic bonds, and bonding of Al2Y and TiB2 mainly consists of covalent and metallic bonds, in which all covalent bonds contain σ bond. Based on band structure and DOS, they have a positive metallic conductivity. In experimental analysis, Li could transform Mg matrix from hcp to bcc, and TiB2 could refine α-Mg. Except for β-Li alloy, mechanical properties of α-Mg and α+β alloy are obviously enhanced by increasing AlTiB content (as-extruded and as-annealed). During annealing, decomposing AlLi phase in β matrix leads to a strengthening effect of Al solid solution in β matrix. Furthermore, the strengthening effect presents more noticeable with increasing temperature.

Effects of LaB6 on the high-temperature oxidation behavior of TiC+TiBx reinforced titanium matrix composite coatings fabricated by laser cladding

The effects of LaB6 addition on the oxidation behavior of TiC+TiBx reinforced titanium matrix composite coatings at the temperature of 600 °C were investigated. The results showed that severe oxidation occurred on the Ti-6Al-4V after oxidation at 600 °C for 50 h. The oxidation weight gain of the (TiC+TiBx)/Ti coating without LaB6 addition (2.43 mg/cm2) was reduced to 49.6% that of the Ti-6Al-4V substrate (4.9 mg/cm2). Though (TiC+TiBx)/Ti coatings improved the oxidation resistance for the surface of Ti-6Al-4V substrates, cracks were easily formed between the coarse rod-like TiB2 and the titanium matrix during the high temperature resulting in less high-temperature oxidation protection. When the LaB6 addition gradually increased from 0 wt% to 1.0 wt%, the oxidation weight gain decreased from 2.43 mg/cm2 to 1.30 mg/cm2, and the linear rate constant Kp1 decreased from 0.04752 to 0.02703. The oxidation law gradually changed from the linear law to the parabolic law when the LaB6 addition increased to 1.5 wt%, which indicated the oxide layer gradually became dense and protective. The oxidation weight gain decreased from 1.23 mg/cm2 to 0.87 mg/cm2 when the LaB6 addition increased from 1.5 wt% to 2.0 wt%, while increased instead when the LaB6 addition increased to 2.5 wt%. An appropriate amount of LaB6 (2.0 wt%) addition significantly improved the oxidation resistance of the coating with the lowest parabolic velocity constant Kp2 = 0.01418 due to the refinement of grain sizes of the coating, especially the refinement of the coarse rod-like TiB2 phase, which decreased the crack forming sensibility and increased the compactness and continuity of the oxidation layer. A small amount of in-situ formatted La2O3 at the grain boundaries acted as a barrier also blocked the ingress of oxygen.

Effects of microstructure characteristics on the mechanical properties and elastic modulus of a new Ti–6Al–2Nb–2Zr–0.4B alloy

A new Ti–6Al–2Nb–2Zr–0.4B alloy was prepared via a vacuum arc remelting process. Furthermore, the changes in the microstructure, mechanical properties, and elastic modulus of the alloy during thermal deformation for forging and rolling were studied. The alloy contained α, β, and TiB phases, and there was a particular phase relationship between TiB and the Ti matrix. The TiB phase was mainly long needle-like in the as-cast samples, short rods with a chain-like distribution in the forging structure, and granular and dispersed evenly after rolling. The mechanical properties’ test results show that the ultimate tensile strength, the elongation at break, and impact toughness from the ingot to forging to plate samples increase from 698 MPa, 5%, and 5 J to 814 MPa, 13.5%, and 41 J and then to 838 MPa, 16%, and 48 J, respectively. Conversely, the elastic modulus decreased gradually from 128.8 to 124.3 and finally to 122.2 GPa. Fractography analysis of the samples revealed a completely ductile fracture mode in the plate samples and a mixed mode of brittle and ductile fractures in the forging samples. Conversely, the ingot samples showed a brittle cleavage fracture with a river pattern.

MICROSTRUCTURE EVOLUTION OF IN SITU COMPOSITE COATINGS FABRICATED BY LASER CLADDING WITH DIFFERENT POWERS

In situ reaction-synthesized TiB-reinforced titanium-matrix composite coatings were fabricated using the rapid, non-equilibrium synthesis technique of laser cladding. The Ti and B mixture was the original powders, while the Ti-matrix composite coatings enhanced with TiB were treated on a Ti-6Al-4V surface with different laser scan powers of 2.5 kW, 3.0 kW and 3.5 kW. The phase composition, microstructure evaluation, and microhardness of the cladding coatings were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and microhardness. The composite coatings mainly consist of black fishbone-shaped -Ti dendrites and white needle-like TiB phases. The microstructure evolution from the top to the bottom of the coatings was investigated. The TiB reinforcement dispersed homogeneously in the composite coatings and a fine microstructure was obtained in a sample fabricated with a laser power of 3.0 kW. The microhardness of the cladding coatings fabricated by different powders was over 2-fold greater than that of the Ti-6Al-4V titanium alloy substrate and achieved a maximum average of 792.2 HV with the laser power of 3.0 kW. The microstructures and properties of the coatings were changed by adjusting of the laser cladding power. The effects of the laser scan power on the microstructure, hardness and friction and wear properties of the laser cladding coatings were investigated and discussed.

MICROSTRUCTURE EVOLUTION OF IN SITU COMPOSITE COATINGS FABRICATED BY LASER CLADDING WITH DIFFERENT POWERS

In situ reaction-synthesized TiB-reinforced titanium-matrix composite coatings were fabricated using the rapid, non-equilibrium synthesis technique of laser cladding. The Ti and B mixture was the original powders, while the Ti-matrix composite coatings enhanced with TiB were treated on a Ti-6Al-4V surface with different laser scan powers of 2.5 kW, 3.0 kW and 3.5 kW. The phase composition, microstructure evaluation, and microhardness of the cladding coatings were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and microhardness. The composite coatings mainly consist of black fishbone-shaped -Ti dendrites and white needle-like TiB phases. The microstructure evolution from the top to the bottom of the coatings was investigated. The TiB reinforcement dispersed homogeneously in the composite coatings and a fine microstructure was obtained in a sample fabricated with a laser power of 3.0 kW. The microhardness of the cladding coatings fabricated by different powders was over 2-fold greater than that of the Ti-6Al-4V titanium alloy substrate and achieved a maximum average of 792.2 HV with the laser power of 3.0 kW. The microstructures and properties of the coatings were changed by adjusting of the laser cladding power. The effects of the laser scan power on the microstructure, hardness and friction and wear properties of the laser cladding coatings were investigated and discussed.

High-strength superelastic as-cast Ni50.9Ti49.1-TiB2 in-situ composites

In this study, as-cast Ni50.9Ti49.1−TiB2 in-situ composites were prepared by adding boron in the vacuum induction melting (VIM) process. With boron content of 1 at.%, TiB2 phases appear in the form of flakes at grain boundaries of the NiTi alloy matrix. These TiB2 flakes are two dimensional in geometry, featured with an ultrafine thickness less than 200 nm and two other dimensions up to ~20–60 μm. Increasing boron content to 2.4 at.% alters the morphology of TiB2 from discrete flakes to agglomerative clusters. This morphological dissimilarity has noticeable impact on resulting mechanical properties, superelasticity and shape memory effect. Overall, the NiTi-1at%B composite outperforms both the monolithic Ni50.9Ti49.1 alloy and the NiTi-2.4 at%B composite. More specifically, it exhibits complete superelasticity for pre-strains below 4% and up to 4.3% recoverable strain for 6% pre-strain, which is comparable to the pure as-cast Ni50.9Ti49.1 alloy. Meanwhile, the corresponding strength under 6% pre-strain reaches 1800 MPa, 20% higher than that of Ni50.9Ti49.1. In compression, the yield strength is 65% higher than that of pure Ni50.9Ti49.1. Moreover, a shape memory recovery ratio of 45.5%, slightly below 48.6% of the monolithic NiTi, was also achieved in NiTi-1at%B. This indicates that the addition of 1 at.% B can effectively improve the strength of NiTi while maintaining its superelasticity and shape memory effect.

Ti6Al7Nb-based TiB-reinforced composites by selective laser melting

The alloy Ti6Al7Nb with the in situ reinforcement of TiB has been processed by selective laser melting (SLM). Premixed Ti6Al7Nb-xTiB2 powders were used for the powder bed. The microstructure of the Ti6Al7Nb alloy was characterized by martensite (αʹ), while the addition of TiB2 led to a bimodal microstructure with refined features as a result of in situ formation of fine TiB phase. A prismatic ││BD fiber texture was evident in all samples, though the texture formation was found to be affected by the change in the phase transformation pathway due to the formation of TiB. Higher hardness and yield strength (YS) in the composites as compared to the base material are attained. The examination of corrosion response revealed a lower corrosion current (Icorr) value for all the specimens in simulated body fluid (SBF) in comparison to Ti6Al4V alloy. The improved mechanical behavior and better corrosion resistance indicate the potential of SLM-processed Ti6Al7Nb/TiB composite as a suitable replacement for Ti6Al4V alloys for bio-implants.

Formation of core-shell structure in W-added B4C-based composites

B4C-TiB2-SiC composites with W addition were successfully prepared by spark plasma sintering with B4C, TiB2, SiC, and W as raw materials. The XRD results indicate that the main phases of the composites are B4C, TiB2, SiC, and W2B5. A large number of core-shell structures were observed in the composites with the introduction of W. It is determined that the core is the TiB2 phase and the shell is a (Ti, W) B2 solid solution by EDS, EBSD, and TEM characterization methods. The core-shell structure is conducive to the deflection of cracks, thereby improving the fracture toughness of the composites. As a result, with the increase of W addition from 0 to 5 vol%, the fracture toughness of composites increased from 3.96±0.25 to 5.14±0.23 MPa m1/2, the Vickers hardness improved from 20.24±0.22 to 28.35±0.22 GPa.

Effect of Gd on microstructure and refinement performance of Al-5Ti-B alloy

Al-5Ti-B and Al-5Ti-B-Gd master alloy refiners were fabricated by fluorine salt casting method. The microstructure and phase constitution of the master alloys were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that Al-Ti-B alloy refiner consists of Al3Ti phase and TiB2 phase. After Gd is introduced into the intermediate alloy, Ti2Al20Gd phase appears in the alloy, the size of Al3Ti is significantly reduced, and Ti-Al-Gd phase is found in the edge of Al3Ti phase. At the same time, some independent Ti-Al-Gd phases appear in local areas, which are Ti2Al20Gd phase determined by micro-area electron diffraction analysis. Analysis and calculation results of the high-resolution images of the Ti2Al20Gd/Al structure show that there is no other compound at the junction between the Ti2Al20Gd phase and Al, and Ti2Al20Gd phase has a great difference in atomic space with the α-Al, which cannot be directly used as heterogeneous nucleus. But, after being decomposed in the aluminum melt, the Ti2Al20Gd phase can promote the refinement effect of the refiner. In the Al-Ti-B-Gd master alloy, there are many dispersed Al3Ti particles with a size of less than 1 µm, which can promote the Al-5Ti-B refining effect.

Role of TiCN addition on the characteristics of reactive spark plasma sintered ZrB2-based novel composites

The present investigation was carried out to illustrate the effect of TiCN on the microstructure development of spark plasma sintered fully dense ZrB2-based ceramics. The microstructural observations, X-ray diffraction patterns, and field emission-electron probe microanalysis revealed the presence of the (Zr,Ti)B2 and ZrCN phases in the final microstructures of the prepared composites. The advancement of a chemical reaction between TiCN and ZrB2 was suggested over the sintering process through the ZrCN and TiB2 phases formation. Although the ZrCN compound was stable during the sintering process, the generated TiB2 was dissolved into the ZrB2 matrix, forming a (Zr,Ti)B2 solid solution. The composition of this solid solution was roughly uniform in the ternary samples, thanks to the role of SiC in grain-refining, contrary to the ZrB2-TiCN composite with a heterogenous composition. Ultimately, the Vickers hardness and elastic modulus of the (Zr,Ti)B2 matrix in the ternary system were measured to be 29.3 GPa and 450.8 GPa, respectively.

Influence of 2D forging processes and boron contents on the microstructures and mechanical properties of near α titanium alloys

2D forging processes are adopted to tailor the microstructures and mechanical properties of near α titanium alloys with different boron contents and the evolutions of the microstructures and mechanical properties of the acquired alloys are carefully characterised. Maximum texture intensities decrease with increasing boron contents, thereby illustrating the improvements in the homogeneity of the microstructures. The distribution of TiB whiskers in the 3D space exhibits a near-columnar arrangement around boundaries of squashed and elongated prior β grains along the stretching direction. Increases in the contents of equiaxed α grains with increasing TiB contents are ascribed to enhancements in recrystallisation due to the promotion effects of the TiB phase and increases in β transus temperatures. Boron exhibits excellent refinement effects on the alloy matrices, and the refinement degree increases with increasing boron contents. The proportions of low-angle grain boundaries decrease whilst the corresponding proportions of high-angle grain boundaries increase with increasing boron contents. The ultimate and yield strengths of the alloys increase at room temperature (RT) and 650 °C. Elongations exhibit a decreasing trend at RT but are maintained at 650 °C. At RT, cleavage fractures of the TiB whiskers determine the evolution law of elongation. The fracture characteristics of alloy matrices exhibit a transformation from a mixture of tearing lamellae and dimples to dimples only. At 650 °C, the alloy matrices are characterised by ductile fractures with numerous dimples. Er containing particles facilitate the fracture of alloy through cooperative effects with TiB whiskers.

High power diode laser alloying of TiB2 and amorphous-boron with titanium: Phase, microstructure and hardness analyses

Laser alloying creates a new alloy or ceramic composite coating with improved surface properties of materials. This work has developed a hard coating by high power diode laser alloying of preplaced TiB2 and amorphous boron (a-B) layer with Cp-Ti and Ti6Al4V substrates under argon and nitrogen gas shielding, which respectively termed as laser boriding and boronitride techniques. The composite coating was investigated by X-ray diffraction, Energy Dispersive X-ray, Elemental mapping, Optical microscopy and FESEM and Vickers hardness analyses. A simple analytical equation was employed to estimate surface temperature to correlate phase formation behavior. The XRD revealed the formation of TiB2 and TiB phases in the borided surface and TiB2, TiB, Ti4N3B2 phases in the laser boro-nitrided surface. The EDAX and elemental mapping confirmed the boron and nitrogen in the laser boro-nitrided cross section. The optical and scanning electron microscopy revealed that coating predominantly consists of TiB ceramic precipitates. A high hardness in the range 1217–3351 HV0.2 was obtained in the laser borided and boro-nitrided coating cross sections, due to the formation of TiB2 and Ti-B-N phases.

Microstructures and mechanical properties of 4 wt%TiB2/Al-Si-Cu-Zn (T6) composite thin-walled shell housing fabricated by high pressure die casting

The application demand of lightweight high-quality aluminum alloy parts in automotive and aerospace fields is increasingly. In aluminum matrix composites, reinforcing particles can significantly improve the performance of the matrix. In this paper, the microstructures and mechanical properties of die-cast 4 wt%TiB2/Al-9Si-3Cu-0.8Zn composite were systematically analyzed by x-ray diffraction, optical microscope, scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy and tensile testing. The composite was successfully fabricated from an Al-K2TiF6-KBF4 system by in situ melting technique. The research results show that the average grain sizes of the α-Al phase gradually decreased with the increase of filling distance. And the TiB2 particles were distributed around eutectic Si in irregular polyhedral morphology or nearly circular shape. Meanwhile, the crystal structures of Ti-B compound and long needle shaped nano-sized precipitated were identified and analyzed, and they were found to be TiB2 and Al2Cu phase, respectively. Tensile testing results show that the mechanical properties of die-cast composite clearly increase after T6 heat treatment. The yield strength, ultimate tensile strength and elongation could reach 311 MPa, 379 MPa and 2.8% respectively, with the best injection velocity (1.8 m s−1). The significantly enhancement of mechanical properties of composite after T6 heat treatment was mainly due to the introduction of TiB2 reinforcing phase and the precipitation of Al2Cu precipitate in the aging stage. The results implied that the introduction of TiB2 reinforced particles could improve the mechanical properties of die castings, which has an important guiding role for its practical application.

Effects of Pr-Cu-Ti intergranular addition on microstructure and magnetic properties of heavy-rare-earth-free Nd-Fe-B sintered magnets

By intergranular addition of Pr-Cu-Ti alloy powders in the Nd-Fe-B sintered magnets with the normal B component, we propose an approach to the optimization of grain boundary and local Nd-Fe-B composition system. The coercivity is enhanced from 1.42 to 1.86 T, while further addition leads to a reduction in remanence and coercivity. The analyses of phase composition reveal that Ti mainly exists in the form of metallic Ti alloy, and part of Ti combines with B to form the TiB2 phase after the liquid phase sintering process. This process results in a consumption of B in the local Nd-Fe-B composition system and a change of the grain boundary component, which contributes to the formation process of the RE6(Fe,M)14 phase after the annealing process. Therefore, with the modification of grain boundary and composition system, the intergranular addition of Pr-Cu-Ti induces the generation of continuous thin grain boundary phases. It promotes the intergrain exchange decoupling, increasing the coercivity in the annealed magnet. While the excess addition results in the segregation of TiB2, as well as the precipitation of TiB2 into the Nd-Fe-B phase, which leads to structural defects. Thus, the further effort for the addition alloy with Ti to reduce the deterioration of the microstructure will lead to further improvement in magnetic properties.

Dense and core‐rim structured B4C‐TiB2 ceramics with Mo‐Co‐WC additive

AbstractB4C‐TiB2 ceramics (TiB2 ranging 5~70 vol%) with Mo‐Co‐WC as the sintering additive were prepared by spark plasma sintering. In comparison with B4C‐TiB2 without additive, the enhanced densification was evident in the sintered specimen with Mo‐Co‐WC additive. Core‐rim structured grain was observed around TiB2 grains. The interface of the rim between TiB2 and B4C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B4C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B2 rim around the TiB2 core may occur as a result of the solid solution and dissolution‐precipitation between TiB2 phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB2 content increased, alongside the decreased hardness. B4C‐30 vol% TiB2 specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m1/2.

Characterization of reactive spark plasma sintered (Zr,Ti)B2–ZrC–SiC composites

This investigation aims to evaluate the influence of SiC introduction on the microstructure development, mechanical characteristics, and densification behavior of (Zr,Ti)B2–ZrC materials. Two specimens, with/without SiC addition, were manufactured from the starting materials of ZrB2 and TiC by reactive spark plasma sintering (SPS) at 1800 °C under 30 MPa for 5 min. Both samples reached relative density values higher than 99%; however, the SiC addition improved this value by ~0.5%, standing at 99.9%. The SiC incorporation into the (Zr,Ti)B2–ZrC system led to an ultrahigh temperature ceramic (UHTC) with considerable hardness and elastic modulus. The TiC additive was completely consumed over the sintering process, participating in the in-situ formation of TiB2 and ZrC as a result of a chemical reaction with the ZrB2 matrix. Thanks to the diffusion of Ti and Zr atoms into the ZrB2 and TiB2 phases, respectively, a solid-solution of (Zr,Ti)B2 formed with various compositions in different areas. Thanks to the synergistic effects of grain refinement and solid-solution formation, the (Zr,Ti)B2–ZrC–SiC sample reached excellent mechanical properties such as an elastic modulus of 495 GPa and a hardness of 31.2 GPa.

Spark plasma sintering of B4C and B4C-TiB2 composites: Deformation and failure mechanisms under quasistatic and dynamic loading

Spark plasma sintering (SPS) was employed to consolidate powder specimens consisting of B4C and various B4C-TiB2 compositions. SPS allowed for consolidation of pure B4C, B4C-13 vol.%TiB2, and B4C-23 vol.%TiB2 composites achieving ≥99 % theoretical density without sintering additives, residual phases (e.g., graphite), and excessive grain growth due to long sintering times. Electron and x-ray microscopies determined homogeneous microstructures along with excellent distribution of TiB2 phase in both small and larger-scaled composites. An optimized B4C-23 vol.%TiB2 composite with a targeted low density of ∼3.0 g/cm3 exhibited 30–35 % increased hardness, fracture toughness, and flexural bend strength compared to several commercial armor-grade ceramics, with the flexural strength being strain rate insensitive under quasistatic and dynamic loading. Mechanistic studies determined that the improvements are a result of a) no residual graphitic carbon in the composites, b) interfacial microcrack toughening due to thermal expansion coefficient differences placing the B4C matrix in compression and TiB2 phase in tension, and c) TiB2 phase aids in crack deflection thereby increasing the amount of intergranular fracture. Collectively, the addition of TiB2 serves as a toughening and strengthening phase, and scaling of SPS samples show promise for the manufacture of ceramic composites for body armor.

Concentrated solar power used in preparation of Ti – B4C composites

Concentrated solar power was employed to sinter compacts of Ti + 15 vol% B4C powder mixture. The sintering experiments were performed under protective argon atmosphere at different temperatures and sintering time without external pressure. The sintering experiments were done in 40 kW horizontal solar furnace (SF40) at Plataforma Solar de Almeria (PSA), Spain.The in situ sintering behavior of the Ti – B4C mixture is significantly affected by exothermic reaction of titanium with B4C. In the solar furnace the ignition temperature of this reaction was found to be around 1380 °C. Therefore, the exothermic reaction of Ti + B4C makes the controlling of the solar sintering of these composites very difficult.The optimal temperature of solar sintering was found slightly below 1340 °C for 30 min. No significant reduction of porosity was observed: All samples have more or less the same final porosity value as green compacts prior sintering. The prepared composite samples are brittle. Decomposition of boron carbide led to the creation of TiB2, TiC and complex TiBxC1-x phases which were confirmed by microstructural investigations.