Outer Titanium Research Articles

Improving fatigue initiation life of open-hole fibre metal laminates by laser shock peening

Although drilling open holes in fibre metal laminates reduces weight, it brings potential crack initiation sites. This paper investigates the effect of laser shock peening (LSP) on fatigue performance of open-hole titanium-based carbon-fibre/epoxy laminates (Ti-CF FMLs). A method based on multi-step simulation was proposed for the reconstruction of LSP induced residual stress field in open-hole Ti-CF FMLs. The results show that the fatigue initiation life of open-hole Ti-CF FMLs is improved by 22.1 %–81.0 % after LSP, depending on the structure of FMLs and the applied fatigue load. The improved fatigue crack initiation life attributes to compressive residual stress generated throughout the entire depth of the hole wall in outer titanium layer in Ti-CF FMLs after LSP. However, LSP leads to the formation of tensile residual stress far from the hole edge, resulting in accelerated propagation of fatigue crack. The fatigue initiation lives of open-hole Ti-CF FMLs before and after LSP were calculated by finite element simulation and theoretical method, showing good consistency.

Tubular PEM electrolysis cells with a 3D-printed oxygen electrode and ALD catalyst coating

Polymer electrolyte membrane electrolysis (PEMEL) is a technology with a major role in linking the hydrogen production to renewable energy resources with a volatile behaviour such as wind and solar. High amounts of precious metals and a labour intensive production also make it a cost intensive technology. A tubular cell design has the potential to reduce production costs by co-extrusion of cells which feature a reduced sealing length. For the inner half cell, additive manufacturing (AM) of titanium offers a high degree of freedom for the electrode design to reach a high electric conductivity and active surface area. In combination with atomic layer deposition (ALD) of iridium catalyst a porous transport electrode (PTE) can be fabricated. Using planar test cell results and model based PTE design, this study demonstrates the feasibility of a tubular PEMEL cell consisting of an additively manufactured, iridium coated anode PTE in the inner half cell, an extruded membrane and a platinum coated graphite felt cathode PTE in the outer half cell. The outer titanium current collector can be replaced by an extruded graphite polymer compound current collector to reduce the amount of titanium without performance losses. The cell is operated at 60 °C in 1 mol L−1 sulphuric acid and experimentally characterized by polarization curves and electrochemical impedance spectroscopy (EIS). At 2.0 V cell potential a current density of ≈450mAcm−2 was reached corresponding to an iridium mass specific current density >1500Ag−1 which is significant larger than literature values.

Monocyclopentadienyltitanium(III) Complexes with Hydridoborato Ligands

The synthesis, properties, and reactivity of monocyclopentadienyltitanium(III) complexes stabilized by hydridoborato (BH3R)− ligands are reported. The reactions of the titanium(IV) trichlorides [Ti(η5-C5H5–nMen)Cl3] with excess LiBH3R (R = H, Me) afford dimeric [{Ti(η5-C5H5–nMen)(BH4)(μ-BH4)}2] (n = 5 (1), 4 (2), 0 (3)) or monomeric [Ti(η5-C5Me5)(BH3Me)2] (4) titanium(III) derivatives. Compound 3 is a thermally unstable oil and decomposes at room temperature forming a mixed-valence TiII/TiIII tetrametallic species [{Ti(η5-C5H5)(BH4)}2{(μ3-B2H6)Ti(η5-C5H5)}2] (5) with dianionic diborane(6) ligands in a rare μ3-κ2:κ2:κ2-B2H6 coordination mode. Density functional theory (DFT) calculations for 5 agree with a triplet ground state with two inner titanium(II) atoms bonded by a single bond and two outer titanium(III) centers. In contrast to 3, the monomeric tetrahydrofuran adduct derivative [Ti(η5-C5H5)(BH4)2(thf)] (6) is a stable solid. Dimeric 1–3 react with 2,6-lutidinium salts (LutH)X (X = BPh4, OSO2CF3) to afford ion pairs, [Ti(η5-C5H5–nMen)(BH4)L2](BPh4) (L = thf, n = 5 (7), 4 (8), 0 (9); L = py, n = 5 (10)), or molecular aggregates, [{Ti(η5-C5Me5)(BH4)(μ-O2SOCF3)}2] (11) and [{Ti(η5-C5H5–nMen)(μ-O2SOCF3)2}x] (n = 5, x = 3 (12); n = 4, x = 4 (13)), via formation of H2 and (Lut)BH3. Diamagnetic titanium(II) derivatives [{Ti(η5-C5Me5)(μ-H)}2{(μ-H)2Al(BH3R)(thf)}2] (R = H (14), Me (15)) were isolated in reactions of complexes 1 and 4 with LiAlH4 in tetrahydrofuran.

Fatigue Life Optimized Layer Architecture of Ultrafine‐Grained Al–Ti Laminates Under Bending Stresses

Fatigue of metallic components is an important aspect in mechanical engineering. For example, the repeated pressure differences result in the fatigue of the fuselage of aircrafts. These high demands require the application of endurable and lightweight materials. In this context, laminated metal composites produced by the accumulative roll bonding process can fulfill both aspects: outstanding mechanical strength of lightweight materials, due to an ultrafine‐grained microstructure, combined with the possibility to produce fatigue‐resistant materials by varying the stacking order of the laminated metal composites. This work investigates laminated metal composites consisting of aluminum AA2024 and titanium grade 1 layers with different stacking orders in respect to their three‐point bending fatigue properties. Additional finite element method (FEM) calculations of the stress distributions in the laminated metal composites are used to explain the results. The mechanical properties of the laminates with an outer aluminum or titanium layer are discussed based on the investigations of nanohardness and crack propagations. Although maximum bending stresses at the sheet surface of laminates with outer Titanium layer are higher than in monolithic materials, these laminates exhibit good lightweight potentials due to the weight reducing aluminum in inner layers.

Shaping the structure and properties of titanium and Ti6Al7Nb titanium alloy in low-temperature plasma nitriding processes

Plasma nitriding of titanium Grade 2 and Ti6Al7Nb titanium alloy at 730 °C was used to produce nitrided surface layers with an outer zone consisting of nanocrystalline titanium nitride - TiN, and a Ti2N zone right above the αTi(N) diffusion area. The paper presents a comparison of structure (TEM, SEM), phase composition (XRD, SAED) surface topography (AFM, optical profilometer), corrosion (potentiodynamic method), tribological properties (‘ball-on-disc’), and adhesion (scratch-test) of TiN + Ti2N + αTi(N) type nitrided surface layers produced on Grade 2 titanium and Ti6Al7Nb titanium alloy using conventional glow-discharge nitriding (so called glow discharge nitriding at the cathode potential) and with the use of an ‘active screen’ (glow discharge nitriding at plasma potential). A reduction of cathodic sputtering in the plasma potential process made it possible to produce surface layers maintaining a high smoothness of the titanium surfaces. Due to the low surface roughness and the high compressive residual stress of the sample after nitriding at plasma potential, ‘ball-on-disc’ test results showed the lowest coefficient of friction and the lowest penetration depth for this layer and very good adhesion of the layer to the substrate – i.e. Ti6Al7Nb titanium alloy. Nitriding of titanium alloy at cathode potential increased the corrosion potential value and slightly decreased corrosion current density. The corrosion current density of the sample nitrided at plasma potential was similar to initial state Ti6Al7Nb titanium alloy. The nitriding process type (cathode potential or plasma potential) used to produce TiN + Ti2N + αTi(N) surface layers on Ti6Al7Nb titanium alloy has an influence on the microstructure of the layer, its residual stress, in particular its TiN outer titanium nitride zone, its thickness, and on its properties such as wear and corrosion resistance.

Man as a living bioreactor: Long-term histological aspects of a mandibular replacement engineered in the patient’s own body

In 2016, we reported the world’s first reconstruction of a mandibular discontinuity defect using a custom-made bone transplant that had been prefabricated in the gastrocolic omentum using tissue engineering strategies. However, the tissue of an engineered human neomandible has not been evaluated histologically until now. The current study assessed the long-term histological characteristics of biopsies of the neomandible 9months after transplantation. Histological analysis showed an increased amount of vital mineralized bone tissue after 10months, in comparison to biopsies obtained earlier. The engineered bone covered the surface of the bone substitute material but also grew out typical structures of cancellous bone tissue without a core of BioOss. The amount of induced bone tissue was 32% in the biopsy. In addition, the soft tissue showed an alignment of the connective tissue fibres parallel to the trabecular bone. Increasing time and mechanical forces at the mandible led to an increased amount of mineralized tissue and remodelling of the connective tissue fibres after transplantation. Further research should focus on developing advanced scaffold materials, as the outer titanium mesh cage leads to complications.

Bio-inspired sandwich-structured carbon/silicon/titanium-oxide nanofibers composite as an anode material for lithium-ion batteries

A bio-inspired sandwich-structured carbon/silicon/titanium-oxide nanofibers composite is fabricated based on the self-assembly technique by using cellulose substance as both the carbon source and the structural scaffold. It holds the hierarchical structure of the initial cellulose substance. And it is composed of thin silicon layer sandwiched between the carbon nanofiber and the outer titanium oxide coating layer consisting of anatase titania nanoparticles with oxygen defects. Owing to the synergetic effect of the porous carbon nanofiber and titanium oxide coating layer, as well as its unique three-dimensional network structure, this nanocomposite shows enhanced lithium storage properties. For the composite with 24.1wt% of titanium oxide, it delivers a stable reversible capacity of ca. 792.6mAhg−1 at a current density of 100mAg−1 after 160 discharge/charge cycles, which superiors to the nanofibrous silicon and carbon/silicon matters as well as the carbon/silicon/titanium-oxide composites with low titanium oxide content therein.

Design of an Yb-169 source optimized for gold nanoparticle-aided radiation therapy.

To find an optimum design of a new high-dose rate ytterbium (Yb)-169 brachytherapy source that would maximize the dose enhancement during gold nanoparticle-aided radiation therapy (GNRT), while meeting practical constraints for manufacturing a clinically relevant brachytherapy source. Four different Yb-169 source designs were considered in this investigation. The first three source models had a single encapsulation made of one of the following materials: aluminum, titanium, and stainless steel. The last source model adopted a dual encapsulation design with an inner aluminum capsule surrounding the Yb-core and an outer titanium capsule. Monte Carlo (MC) simulations using the Monte Carlo N-Particle code version 5 (MCNP5) were conducted initially to investigate the spectral changes caused by these four source designs and the associated variations in macroscopic dose enhancement across the tumor loaded with gold nanoparticles (GNPs) at 0.7% by weight. Subsequent MC simulations were performed using the EGSnrc and norec codes to determine the secondary electron spectra and microscopic dose enhancement as a result of irradiating the GNP-loaded tumor with the mcnp-calculated source spectra. Effects of the source filter design were apparent in the current MC results. The intensity-weighted average energy of the Yb-169 source varied from 108.9 to 122.9 keV, as the source encapsulation material changed from aluminum to stainless steel. Accordingly, the macroscopic dose enhancement calculated at 1 cm away from the source changed from 51.0% to 45.3%. The sources encapsulated by titanium and aluminum/titanium combination showed similar levels of dose enhancement, 49.3% at 1 cm, and average energies of 113.0 and 112.3 keV, respectively. While the secondary electron spectra due to the investigated source designs appeared to look similar in general, some differences were noted especially in the low energy region (<50 keV) of the spectra suggesting the dependence of the photoelectron yield on the atomic number of source filter material, consistent with the macroscopic dose enhancement results. A similar trend was also shown in the so-called microscopic dose enhancement factor, for example, resulting in the maximum values of 138 and 119 for the titanium- and the stainless steel-encapsulated Yb-169 sources, respectively. The current results consistently show that the dose enhancement achievable from the Yb-169 source is closely related with the atomic number (Z) of source encapsulation material. While the observed range of improvement in the dose enhancement may be considered moderate after factoring all uncertainties in the MC results, the current study provides a reasonable support for the encapsulation of the Yb-core with lower-Z materials than stainless steel, for GNRT applications. Overall, the titanium capsule design can be favored over the aluminum or dual aluminum/titanium capsule designs, due to its superior structural integrity and improved safety during manufacturing and clinical use.

A facile approach for the synthesis of magnetic separable Fe3O4@TiO2, core–shell nanocomposites as highly recyclable photocatalysts

A facile and efficient approach for the fabrication of Fe3O4@TiO2 nanocomposites with a good core–shell structure has been demonstrated. The approach employed involved the coating of successive titania shell on Fe3O4 core using a mixed solvent method with the catalysis of ammonia followed by the crystallization of TiO2 through solvothermal method. The as-obtained core–shell structure was composed of a central Fe3O4 core with a strong response to external fields, whereas the outer titanium oxide coating was useful for the degradation of organic contaminants. The results showed that Fe3O4@TiO2 nanocomposites exhibited high degree of crystallinity, excellent magnetic properties at room temperature. Furthermore, the as-prepared Fe3O4@TiO2 nanocomposites exhibited good photocatalytic activity toward the degradation of Rhodamine B (RhB) solution, which meant that they can be used as efficient and conveniently recoverable photocatalysts. In addition, the mechanism of coating by ammonia catalysis was also investigated.

WE‐A‐108‐03: Design of a New Yb‐169 Source Optimized for Gold Nanoparticle‐Aided Radiation Therapy

Purpose: To find an optimum design of a high‐dose rate Yb‐169 brachytherapy source for gold nanoparticle‐aided radiation therapy (GNRT). Previous studies suggested that the gamma‐ray energy spectrum of Yb‐169 could be almost ideal for a brachytherapy implementation of GNRT. The current study was aimed to design a new Yb‐169 source that would maximize dose enhancement during GNRT while meeting practical constraints for manufacturing a clinically‐relevant brachytherapy source. Methods: Monte Carlo simulations were conducted using the MCNP5 code to determine spectral changes caused by four different Yb‐169 source designs and associated variations in macroscopic dose enhancement across the tumor/ICRU tissue loaded with gold nanoparticles at 0.7% by weight. The first three source models had a single encapsulation made of aluminum, titanium, or stainless steel, while the last source model adopted a dual encapsulation design with an inner aluminum capsule and an outer titanium capsule. Results: The results showed spectral changes dependent on source design and their correlation with dose enhancement. The aluminum‐encapsulated source showed the lowest intensity‐weighted average energy of 108.9 keV, and the greatest dose enhancement of 51.0% at 1 cm away from the source center. The sources encapsulated by titanium and aluminum/titanium combination showed similar levels of dose enhancement, 49.2% and 49.3%, and average energies of 113.3 keV and 112.5 keV respectively. The source encapsulated with stainless steel exhibited the smallest dose enhancement, 43.8%, and the highest average energy of 126.6 keV. Conclusion: The current investigation suggests that the attainable macroscopic dose enhancement during GNRT with an Yb‐169 source can be further increased by encapsulating the Yb‐core with aluminum, titanium or aluminum/titanium combination, instead of stainless steel. Due to its structural integrity and improved safety during manufacturing and clinical uses, the dual encapsulation design would be preferred. Supported by DOD/PCRP grant W81XWH‐12‐1‐0198; DOD/PCRP grant W81XWH‐12‐1‐0198

THERMAL STRAIN MEASUREMENT OF A DOUBLE RING STRUCTURE USING DIGITAL IMAGE CORRELATION METHOD

Thermal output is a large error source in the thermal deformation measurement of specimens under temperature change when a strain gage is used. Although several methods have been developed and used to compensate thermal output, the range of measuring temperature is limited to several hundred degrees C. In this study, we used a digital image correlation (DIC) method to measure the full-field thermal deformation and strain of a double ring structure consisting of an inner aluminum ring and an outer titanium ring. Thermal deformation of the ring was measured up to 200 degrees C, and a finite element simulation for the heating condition of the double ring structure was performed. The deformation and strain results from the DIC method and simulation were in good agreement.

Microstructure in Pressureless-Sintered Iron-Containing Hydroxyapatite/Titanium Composites

Pure hydroxyapatite (HA) is brittle and it cannot be directly used for the load-bearing biomedical applications. Aim of this paper was to present a new iron-containing hydroxyapatite/titanium composites synthesized via pressureless sintering at a relatively low temperature of 1000°C using nano-sized HA powders and Ti-33%Fe mixed powders. The microstructure and composition of the new type composites were evaluated. The results showed that the uniformly distributed reinforcing particles had a unique and favorable core/shell microstructure after sintering that consisted of outer titanium and inner iron. The mechanism for the formation of the core/shell structure was discussed. The addition of iron reduced the decomposition rate of HA and the interaction between HA and titanium.

Damage Behaviour of Ti/GFRP Laminates under Low-Velocity Impact Loading

In the present paper, the impact responses and overall damages of Fibre-Metal Laminates based on titanium alloys and glass fibre-reinforced polymers (Ti/GFRP) as Ti/FRP laminate system were evaluated. Low-velocity impact tests using a drop-weight tower were conducted for the cross-plied GFRP laminates and the Ti/GFRP laminates, and the impact responses during impact loading were obtained. Impact damages such as cracks in titanium layer and delamination of titanium-GFRP interface or matrix cracks and interlaminar delamination in GFRP layer were observed from the impact direction. From the experimental evidence, it was found that the Ti/GFRP laminates showed same impact damage modes as of other types of Fibre-Metal Laminates. Internal damages in the Ti/GFRP laminates were restrained by the reinforcing effect of titanium and adhesive layer compared to the cross-plied GFRP laminates. The Ti/GFRP laminates showed two patterns of the impact responses and damages with the threshold impact energy of about 4.8J. With higher impact energy than this threshold, single crack was presented in titanium layer at non-impacted side. The interlaminar delamination area in GFRP layer increased sharply due to the occurrence of this crack. Numerical analysis model that represent the impact behaviour of the Ti/GFRP laminates using finite element method was suggested based on the damage observations. The impact responses obtained by the dynamic analyses agreed well with the experimental results. The calculated area of interlaminar delamination in GFRP layer as a function of impact energy showed same behaviour as seen in the experiments. As a consequence, it was shown by the analysis as well that the drastic increase in the internal damage area of the Ti/GFRP laminates was induced by the fracture in outer titanium layer under the out-of-plane impact loading.

Toughening mechanisms in iron-containing hydroxyapatite/titanium composites

Pure hydroxyapatite (HA) is brittle and it cannot be directly used for the load-bearing biomedical applications. The purpose of this investigation was to develop a new iron-containing HA/titanium composite via pressureless sintering at a relatively low temperature with particular emphasis on identifying the underlying toughening mechanisms. The addition of iron to HA/titanium composites led to a unique and favorable core/shell microstructure of Ti–Fe particles that consisted of outer titanium and inner iron, and good interfacial bonding with HA matrix. While the relative density, hardness and Young's modulus reduced, the flexural strength, fracture toughness, fatigue resistance, and the related fracture surface roughness increased significantly with increasing amount of Ti–Fe particles. Different toughening mechanisms including crack bridging, branching and deflection were observed in the composites, thus effectively increasing the crack propagation resistance and resulting in a substantial improvement in the mechanical properties of the composites.

Fixation and Bone Remodeling Around a Low Stiffness Stem in Revision Surgery

Femoral stems with reduced stiffness have the potential of decreasing stress shielding and could be an alternative in revision surgery when restoration of bone stock is required. We retrospectively reviewed 38 patients (40 stems) with a central core of cobalt-chromium surrounded by a polymer and an outer titanium mesh layer containing a proximal coating of hydroxyapatite/tricalcium phosphate; 30 of the 38 patients (32 hips) had a minimum 2-year followup. We impacted morselized allograft around the stem in 28 of 32 revisions. Repeated radiostereometric examinations showed medial, distal, and posterior migration (median, 0.21 mm, 0.17 mm, and 0.96 mm, respectively) of the femoral head center for up to 6 months followed by stabilization. Measurements of bone mineral density in the seven Gruen zones at 6 months revealed either a decrease (down to a median of 3%), no change, or a slight increase (up to 5%) followed by a further increase up to 2 years in three of the regions (2, 3, and 5). Conventional radiography at 2 years demonstrated graft remodeling and incomplete radiolucent lines in 19 hips, mainly in Regions 1 and 7. Two hips were reoperated on as a result of dislocation, but none of the stems had been revised. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Texture, Tensile Properties and Press Formability of Mg-3Al-1Zn/Ti Clad Sheets Produced by Roll-Bonding

In order to improve corrosion resistance and mechanical properties of magnesium alloys, titanium with high specific strength was warm roll-bonded on the surface of AZ31 magnesium alloy sheets. Although the AZ31 alloy before roll-bonding had a typical basal texture, the AZ31 layer that constitutes a larger part of the clad sheet clearly showed off-basal texture with c-axis inclined by about 10º from the normal direction toward the rolling direction. This texture significantly affected tensile properties of clad sheets, resulting in lower proof stress and higher elongation at the rolling direction than at the transverse direction. In deep drawing tests, the 2-layered clad sheet with an outer titanium layer could be successfully formed at temperatures considerably lower than the limiting forming temperature of an original AZ31 single sheet. This is probably due to an effect of the outer titanium layer bearing tensile stress at a shoulder part of cup and an additional effect of improved deformability by off-basal texture in the AZ31 layer.

Synthesis and Electrosurface Properties of One- and Two-Component Nanostructures

One- and two-component (titanium and aluminum oxides) oxide nanostructures are synthesized by molecular layer-by-layer deposition from the gas phase onto silicon oxide and boehmite substrates. Two-component nanostructures are prepared by the consecutive deposition of nanolayers of aluminum and titanium oxides onto a dispersed silica substrate. Electrosurface properties of thus-prepared samples are studied and compared. It is shown that the positions of the isoelectric point and the point of zero charge of a 5TiO2/5Al2O3/SiO2 composite sample are governed by an outer titanium oxide nanolayer and are similar to those of bulk titanium oxide and a nanostructured film of titanium oxide deposited onto an aluminum hydroxide substrate.

The Yung percutaneous mastoid vent: a medium-term follow-up study.

I designed a percutaneous mastoid vent to provide permanent ventilation to the middle ear. The vent consists of an outer titanium tube that osseointegrates with the mastoid bone and an inner Teflon tube that protrudes into the mastoid antrum. To follow up all patients who had the mastoid vent inserted since 1995. Retrospective study of 14 patients with mastoid vents inserted at the ear, nose, and throat clinic of a district general hospital. All patients had ventilation problems of the ear that failed to respond to conventional treatment. Three patients had persistent otitis media with effusion; 10 had completely collapsed eardrums; and 1 had failed tympanoplasty with recollapsed eardrum. INTERVENTION AND OUTCOME MEASURE: The mastoid vent extrusion rate, surrounding skin reaction, patency of the vent, and functional results were assessed with a follow-up period of 9 to 36 months. Only 1 vent was extruded in a patient who had a previous cortical mastoidectomy. There was no dermatitis around any of the vents. All vents remained patent, and 9 of the 14 ears underwent successful ventilation. Four ears had adhesions within the mastoid antrum, mainly due to a previous cortical mastoidectomy. Six of 8 ears with intact ossicles also had improved hearing. The percutaneous mastoid vent can provide medium-term ventilation to the middle ear.

A novel titanium–oxygen ladder structure supported by calix[4]arene ligands, characterised by synchrotron crystallography

Reaction of an excess of TiCl4 with p-tert-butylcalix[4]arene (H4L1) in toluene led to [{Ti2(µ3-O)Cl2L1}2] 1, presumably via a fortuitous oxidation reaction. The crystal structure of the toluene disolvate, determined using synchrotron radiation single-crystal diffraction facilities, revealed a four-runged Ti4O4 planar ladder core terminated by chloro ligands on the outer titanium atoms. Each of the two calix[4]arene ligands is involved in co-ordination to three of the four titanium atoms, with one oxygen atom in a bridging mode between two metal atoms. This co-ordination enforces an unusual conformation on the ligand, with two opposite aromatic rings almost parallel and the other two splayed widely apart.

Interaction of reactively sputtered titanium carbide thin films with Si, SiO2Ti, TiSi2, and Al

The interactions of reactively sputtered titanium carbide (TixC) films with Si, SiO2, Ti, TiSi2, and Al have been studied using Auger electron spectroscopy, x-ray diffraction, and four-point probe resistance. The TixC films react with Si leading to silicide phases that are not observed when pure Ti reacts with Si. The interaction of TixC with Si is delayed to higher temperatures with increasing carbon content. For x≤1, no interaction is observed even after 900 °C-30 min anneal. For x≥1, the silicide formation leads to phase separation with TiSi2 near the silicon substrate plus an outer titanium carbide layer, which, like all other TixC films investigated, is found to be an effective diffusion barrier to Al penetration up to 500 °C. For x≤1, no interaction with SiO2 is observed up to 900 °C. However, Ti-rich films interact with SiO2 to form titanium oxide. The stoichiometric film adheres to Ti and TiSi2 much better than to Si and SiO2. It does not react with Ti or TiSi2 up to 750 °C. At 900 °C TiC is unstable on TiSi2.