Morphology Of TiC Research Articles

Tribology characteristics of in-situ laser deposition of Fe-TiC

In this paper, the effects of TiC morphology and TiC volume fraction on wear resistance of the laser deposited Fe-TiC were studied. In-situ Fe-TiC clad layers were deposited on an AISI 1030 steel substrate with a fiber laser using dynamic blow technique. Two laser conditions along with two atomic percent ratios, 45:55 and 55: 45, were selected for C:Ti, and Fe percentages were explored with 70, 60,50 and 10wt.%. Results showed that TiC morphology was affected by laser process parameters and powder composition. Optimum wear resistance was found among the samples by conducting wear tests with the ASTM G65-04, dry sand/rubber wheel, low-stress, coarse and abrasive (three-body) test methods. The abrasive characteristics of TiC were compared to WC-12wt.% Ni deposited on a similar substrate measured under identical test conditions. Results showed excellent wear resistance of in-situ TiC. The clad layer's abrasive wear resistance was a factor of 50–70 and 1.2 times higher than that of AISI 1030 steel and WC-12% Ni, respectively.

Effect of Temperature on the Performance of AlTiC Metal Alloys

AlTiC master alloys have been prepared by Contact Reaction Method（CRM）.X-ray diffraction，SEM and EDS were used to analyse the AlTiC master alloys. It showed that morphology and distribution of TiC and Al3Ti particle have correspondingly changed with the transformation of temperature. As a result, the change in morphology and distribution of TiC and Al3Ti particle has considerably affected the gain refining performance of AlTiC master alloys. The result showed that it had excellent grain refining performance for commercially pure aluminum in 800°C.

The influence of combined laser parameters on in-situ formed TiC morphology during laser cladding

In this paper, the effect of laser cladding process parameters on TiC morphology is studied. Results show that laser parameters play a crucial role in morphology of TiC. Dendritic or spherical TiC particles with different distribution are observed depending on applied laser parameters. Two combined parameters, effective energy and powder deposition density, are used in order to study the effect of laser process parameters on TiC morphology.A series of experiments are conducted in constant laser power and scan speed, constant effective energy and constant powder deposition density in order to study the TiC morphologies. Results show that both combined parameters and laser parameters should be considered in order to interpret the results. Laser parameters have crucial role in establishing the TiC morphologies by means of temperature and chemical composition.Hardness results of the clad zone depend on morphologies and distributions of TiC particles in the clad.

Modification and control of TiC morphology by various ways in arc melted TiC/Ti–6Al–4V composites

The effects of carbon sources, cooling rate, alloying elements and heat treatment on the morphology of TiC were investigated in arc melted TiC/Ti–6Al–4V composites. It was observed that different carbon sources of the composites led to different morphologies of TiC, and the carbon source of carbon powder was found to be more useful in restraining the dendritic growth of TiC. Increasing the cooling rate can reduce the size of TiC, and the refinement effect is more obvious in the composite with carbon powder as the carbon source. The addition of 0·3 wt-%Ni promotes the dendritic growth of TiC; however, the TiC particles become fine and dispersed when 0·3 wt-%Sn is added in the composites. TiC particles in the composites can be dissolved and gradually spheroidised with increasing holding time when heat treated at 1050°C.

Effect of the Size of Powder on the Microstructures and Grain Refining Performance of AlTiC Alloys

AlTiC master alloys have been prepared by Contact Reaction Method（CRM）.X-ray diffraction，SEM and EDS were used to analyses the AlTiC master alloys. It showed that morphology and distribution of TiC and Al3Ti particle have correspondingly changed with the change of the size of powder. As a result, the change in morphology and distribution of TiC and Al3Ti particle has considerably affected the gain refining performance of AlTiC master alloys. The result showed that: when the grain size of Ti is much smaller, the effect of refinement is much better.

Effect of laser cladding process parameters on clad quality and in-situ formed microstructure of Fe–TiC composite coatings

Over the past decade, researchers have demonstrated interest in tribology and prototyping by the laser cladding process. In-situ laser cladding enables the formation of a uniform clad by melting the powder to form desired composition from pure powder component.In this research pure Ti, graphite, and Fe with max particle sizes of 40μm (0.04mm) are used for in-situ laser cladding on a steel substrate. The effects of laser parameters on the quality of an in-situ formed TiC–Fe based composite clad are investigated. Laser parameters have an important role in clad quality and crack formation. They affect the bonding between clad/substrate and cooling rate. Diverse microstructures have been detected in the clad. Finally a model is developed in order to explain the formation and morphology of TiC. The melting and solidification stages of TiC formation and matrix confirm the suggested model.TiC particles increase the clad hardness to an average of four times greater than substrate's hardness. Experimental methods such as, XRD and SEM are used for phases characterization.

In situ synthesised TiC particles reinforced Fe based composite coating produced by laser cladding

Fe based composite coating reinforced by in situ synthesised TiC particles has been fabricated from a precursor mixture of ferrotitanium (Fe–Ti) alloy and graphite powders by laser cladding. The microstructure and wear properties were analysed by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction, as well as dry sliding wear test. The results showed that TiC carbides were formed via in situ reaction between ferrotitanium (Fe–Ti) and graphite in the molten pool during laser cladding process. The morphologies of TiC were of dendritic, cubic or flower-like shape; and the TiC carbides were distributed uniformly in the composite coating. Compared to the substrate, the hardness and the wear resistance of the coatings reinforced by TiC particles were significantly enhanced, but the coating possesses a lower friction coefficient.

Microstructure and wear properties of TiC/FeCrBSi surface composite coating prepared by laser cladding

Titanium carbide particles reinforced Fe-based surface composite coatings were fabricated by laser cladding using a 5 kW CO 2 laser. The microstructure, phase structure and wear properties were investigated by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction, as well as dry sliding wear test. The results showed that TiC carbides were formed via in situ reaction between ferrotitanium and graphite in the molten pool during the laser-clad process. The morphology of TiC is mainly cubic and dendritic form; and the TiC carbides were distributed uniformly in the composite coating. The TiC/matrix interface was found to be free from cracks and deleterious phases. The coatings reinforced by TiC particles revealed higher wear resistance and lower friction coefficient than that of the substrate and FeCrBSi laser-clad coating.

The influence of forming processes on the distribution and morphologies of TiC in Al–Ti–C master alloys

Al–Ti–C master alloys were prepared using a melt reaction method. It is found that the distribution and morphologies of TiC are influenced mainly by the synthesis temperature and it is difficult to improve them by increasing the melting temperature once the TiC particles have been formed. It is supposed that different synthesis temperatures result in different forming processes for TiC, which account for the distribution and morphologies of the TiC particles.

Thermal stability of Ti 3AlC 2/Al 2O 3 composites in high vacuum

The thermal stability of Ti 3AlC 2/Al 2O 3 composites in high vacuum was investigated. On the sample surface, Ti 3AlC 2 can decompose with the formation of TiC 0.67 and gaseous Al at first, then Ti evaporation results in the irregular morphology of non-stoichiometric TiC x . At the same time, the amount of Al 2O 3 particles becomes less with increasing the soaking time. Finally, Al 2O 3 particles disappear and a layer of non-stoichiometric TiC x forms on the sample surface. But the bulk Ti 3AlC 2/Al 2O 3 composites always keep stable during the vacuum treatment.

In situ TiC particles reinforced grey cast iron composite fabricated by laser cladding of Ni–Ti–C system

Grey cast iron matrix composite reinforced with in situ synthesized TiC particles has been fabricated successfully from a precursor mixture of nickel, titanium and graphite (Ni–Ti–C) powders by laser cladding. TiC particles with various shapes and sizes were in situ formed mainly during the solidification and most shapes of TiC particles were diversiform according to different contents of Ti–C powder in the Ni–Ti–C system. The morphologies of TiC were of dendritic, flower-like and large blocky shapes. The growth mechanism of the blocky TiC particles with cores is nucleation-growth. Compared to those unreinforced grey cast iron matrix, the hardness and the wear resistance of TiC reinforced grey cast iron composite were significantly enhanced.

Preparation of in situ TiC P/LY12 composite and its microstructure and mechanical properties

Mechanical properties of TiC P/LY12 Al-based composites prepared by an in situ synthesis method were studied. The micro-structure, morphology, and distribution of TiC p particles in the LY12 Al alloy matrix were also investigated by XRD, SEM, and HRTEM. The phase composition of the TiC P/LY12 composites, interfacial structure of TiC particle-to-particle and TiC particle-to-Al matrix, and structure of triple phase among TiC particle, Al 2Cu phase, and Al matrix were also studied. There are no detectable Al 3Ti phases in TiC P/LY12 composites, and a strong cohesive interface between TiC particles and Al-based alloy matrix was observed in the in situ synthesized TiC P/LY12 composites. After heat treatment using T6 procedure, it was found that ultimate strength ( σ b), yield strength ( σ s), and Young's modulus ( E) of TiC P/LY12 composites increased but the elongation ratio decreased with increasing of the mass fraction of TiC particles.

TiC-Reinforced Cast Cr Steels

A new class of materials, namely TiC-reinforced cast chromium (Cr) steels, was developed for applications requiring high abrasion resistance and good fracture toughness. The research approach was to modify the carbide structure of commercial AISI 440C steel for better fracture resistance while maintaining the already high abrasion resistance. The new alloys contained 12Cr, 2.5–4.5Ti, and 1–1.5C (wt.%) and were melted in a vacuum induction furnace. Their microstructure was composed primarily of a martensitic matrix with a dispersion of TiC precipitates. Modification of TiC morphology was accomplished through changing the cooling rate during solidification. Wear rates of the TiC-reinforced Cr steels were comparable to that of AISI 440C steel, but the impact resistance was much improved.

Role of nanoscale TiC particles in batch annealing of Ti stabilised interstitial free steels

The effect of nanoscale TiC precipitates on the annealing texture and mechanical properties of a titanium stabilised interstitial free (Ti-IF) steel in batch annealing has been examined. By pretreating hot rolled Ti-IF steel sheets, materials with different TiC sizes and dispersions are obtained. It is found that the difference in the initial TiC morphology has little effect on the texture and properties of annealed Ti-IF steels. This result deviates from previous findings in the literature regarding the deteriorating effect of fine precipitates on annealing texture in continuous annealing of IF steels. It is believed that the observed deteriorating effect reported in the literature actually results from the pinning effect of solute C atoms from carbide dissolution at high temperature. Batch annealing has a much lower temperature than continuous annealing, so it produces much less carbide dissolution and liberates less solute C atoms into the ferrite matrix, and therefore recrystallisation is little affected.

High-resolution transmission electron microscopy study of crystallography and morphology of TiC precipitates in tempered steel

In spite of the significance of NaCl-type transition-metal carbides in steels, their crystallography and morphology have not been understood on an atomic scale. High-resolution electron microscopy was employed in the present work to examine the crystallography and morphology of TiC particles that precipitated in the quenched and tempered 0.05 wt% C–0.20 wt% Ti–2.0 wt% Ni steel. Plate-like TiC precipitates with a thickness ranging from a couple of atomic layers to 20 nm were observed in steels by tempering at 550, 600 and 800°C. It was found that the Baker–Nutting orientation relationship is always satisfied with the ferrite matrix within about 5° for both the nanosized and the coarse TiC particles. The habit plane of the TiC precipitate is the (100) ferrite plane. A moderate tendency for the faceting of lateral interfaces on the {001} and {011} ferrite planes was found. The presence of interfacial misfit dislocations was revealed by examining the excess lattice fringes terminating at the interfaces between the TiC platelet and the ferrite matrix. The location and number of the excess lattice fringes terminating at the broad plane and the lateral interface were consistent with the mismatch in the atomic arrangement between the Baker–Nutting orientation relationship related TiC and ferrite.

Microstructure and high-temperature wear resistance of a laser surface alloyed γ-TiAl with carbon

TiC reinforced composite coating on γ-TiAl alloy was successfully fabricated by laser surface alloying with carbon. The fine TiC reinforcing phase had a gradient distribution in the coating, and its growth morphology of TiC in laser surface alloyed coating was in unique faceted platelet-like. The composite coating exhibited high hardness and excellent high-temperature sliding wear resistance.

Interfacial Properties Between CVD Diamond and Titanium

The role of carbide and oxy-carbide films in the adhesion of diamond films on commercial pure Ti metal, and a Ti, 6%Al, 4%V substrates was examined. It was found that the carbon to oxygen ratio in an oxy-carbide structure formed at the interface broadly correlates with the adhesive strength of the diamond/substrate bond. Deposition experiments with substrates including titanium and its alloys, suggest the nature of the substrate is important in aiding carbide and subsequently, diamond formation. XPS depth profiling for Ti-6Al-4V indicates that the mode of TiC formation on pure Ti and Ti-6Al-4V is significantly different because of the segregation of aluminium. This contributes to a change of TiC stoichiometry and morphology. SIMS depth profiles also show that the interfacial surface on Ti-6Al-4V contains several percent of aluminium and nitrogen, both at the outermost surface and in the interior of the interfacial layer. The aluminium is enriched at the surface as compared with the bulk concentration.

Growth morphologies and mechanism of TiC in the laser surface alloyed coating on the substrate of TiAl intermetallics

TiC-type MC carbide is an important constituent and strengthening phase for nickel-base superalloys, metal matrix composites (MMCs) and intermetallic matrix composites (IMCs). Its growth morphology, size and distribution have a strong effect on the mechanical properties of materials. In addition, TiC carbide is a typical faceted crystal due to its high Jackson factor. Therefore, the solidification behavior of TiC carbide is an important research subject. In the present study, TiC reinforced composite coatings on the surface of intermetallic alloy γ-TiAl were successfully synthesized by means of laser surface alloying, the growth mechanism and phase morphologies of TiC were investigated as a function of solidification cooling rate. The growth morphology of TiC solidified at a cooling rate of 1.0×10 2 K/s is found to be dendritic, having a platelet/catenulate growth characteristic on dendrite arms. As the solidification cooling rate increases to 2.2×10 2 K/s, the growth morphology of TiC changes to a well-developed dendrite having a three-dimensional network growth characteristic. In spite of the variety of growth morphologies under different solidification conditions, TiC still grows by the lateral growth mechanism. Moreover, the growth kinetics of TiC/Al 3Ti eutectic plays an important role in controlling the carbide growth morphologies.

Nanocrystalline growth and diagnostics of TiC and TiB 2 hard coatings by pulsed laser deposition

Nanocrystalline coatings of TiC and TiB2 were grown by pulsed laser deposition on Si(100) and on X155 steel at low substrate temperatures ranging from 40 °C to 650 °C. A pulsed KrF excimer laser was used with the deposition chamber at a base pressure of 10-6 mbar. The morphology and structure of the films, studied with SEM, XRD, and TEM, showed that nanocrystalline films with a fine morphology of TiC and TiB2 were deposited with a grain size of 10 nm–70 nm at all substrate temperatures. The growth of the polycrystalline coatings possessed a columnar morphology with a preferred orientation. The hardness of the coatings was determined to be 40 GPa and the elastic modulus, 240 GPa. The composition and the kinetics of the plume produced during the pulsed laser deposition of TiC and TiB2 was studied under film growth conditions. The mass analysis of ions of the ejected material was performed by time-of-flight mass spectroscopy (TOF-MS) and showed the presence of Ti+ and C+ during TiC ablation and B+, B2+, and Ti+ during TiB2 ablation. The kinetic energies (KE) of the ions depended on the laser fluence which was between 0.5 eV and 340 eV. The kinetic energy and the evolution of the plasma was studied with a streak camera. The velocity of the plasma was of the order of 106 cm/sec and was linearly dependent on the energy fluence of the laser. The emission spectroscopy of the plasma plume confirmed the atomic neutral and single excited species of Ti. These results show that coating growth basically occurs by the recombination of the ionic species at the surface of the substrate.

Growth of TiB 2 and TiC coatings using pulsed laser deposition

Refractory coatings of TiC and TiB 2 have been grown by pulsed laser deposition on Si(100) and on X155 steel at various substrate temperatures ranging from 40°C–650°C. A pulsed KrF excimer laser was used with the deposition chamber at a base pressure of 10 −6 mbar. The morphology and structure of the films, studied with scanning electron microscopy (SEM), X-ray diffractometry (XRD) and transmission electron microscopy (TEM) analysis, showed that polycrystalline films with fine morphology of TiC and TiB 2 were deposited with grain sizes of 10 nm–70 nm at all substrate temperatures. Shifts in the X-ray diffraction peaks were attributed to the presence of residual stresses in the films, which decreased as the substrate temperature was increased. Finally, the metallic behavior of the coatings was studied by electrical resistivity measurements.