Microhardness Of Ti Research Articles

Исследование структуры и свойств металл-интерметаллидного материала на основе (Ti – Al – Mg)/Ti, полученного методом самораспространяющегося высокотемпературного синтеза совмещенного с прессованием

The method of self-propagating high-temperature synthesis (SHS), combined with pressing, for the first time obtained a metal-intermetallic material based on gorenje products of the layered system (Ti – Al – Mg)/Ti. Exothermic synthesis from elementary powders was carried out at a pressure of 10 MPa, and pressing of the hot synthesis product at a pressure of 250 MPa. The paper demonstrates that as a result of SHS-pressing, an integral connection of the “intermetallic/metal” layers is formed. The main features of microstructure formation, phase composition and strength properties of transition zones at the boundary between reacting SHS compositions Ti – Al – Mg and Ti-substrate are investigated. The thickness of the transition zone between the layers was at least 15 µm. The results of energy dispersion analysis (EDA) showed that magnesium Mg in the synthesized alloy is mainly in the intergranular layers, in the form of a small amount of Ti – Al – Mg compound, which indicates incomplete reaction diffusion between Ti – Al and Al – Mg layers. The microhardness of Ti – Al grains in the synthesized alloy has an average value of 5820 MPa, and the matrix based on Al – Mg is 3980 MPa. The hydrostatic density is 3.3 g/cm3, with a porosity of less than 13 %. As a result, the method of SHS-pressing turned out to reduce the porosity of the resulting Ti – Al – Mg-based alloy by 3 times.

Thermal deformation mechanism of TC11/TC17 linear friction welded joint during isothermal compression

Thermal deformation behavior has a significant effect on the microstructure evolution, crystallographic orientation and microhardness of two-phase titanium alloy. In the paper, the evolution rules of microstructure, texture and microhardness of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si (TC11) and Ti–4Mo–4Cr–5Al–2Sn–2Zr (TC17) linear friction welded (LFWed) joint were systematically discussed during the isothermal compression. Comparing with the high microhardness on the welded zone (WZ) after welding, the microhardness value of the whole joint decreases significantly after the pretreatment and isothermal compressions. There is a close relationship between microtexture and plastic deformation. The electron backscattered diffraction (EBSD) analysis method indicates that the distribution of Schmid factor is very uneven, and most of the crystals are aligned to hard orientation on the TC11 WZ; whereas the high Schmid factors occur, and most of the crystals turn to soft orientation on the TC17 WZ, which lead to the plastic deformation of TC17 side more easily than that of TC11 side. With the increasing compression strains, the ratio of low angle grain boundaries (LAGBs) rises, meanwhile, the mean geometrically necessary dislocations (GND) density increases from 2.79 × 10 14 m −2 to 4.30 × 10 14 m −2 , and the fraction of high Schmid factor also goes up slightly. Those can be attributed to the increased deformation energy with the higher compression, which leads to the accumulated driven force and promotes the rotation of grains toward a specific favourable orientation. The relationship between the microhardness and the crystal texture of the TC11/TC17 LFWed joint. • Rules of microstructure, texture and microhardness of LFWed joint were discussed. • Plastic deformation mechanism of the joint was discussed by the Schmid factors. • The ratio of LAGBs and GND density rises with the increasing compression strains. • Microhardness at the joint is more uniform with the higher isothermal compression.

Structural and Mechanical Properties of Ti⁻Co Alloys Treated by High Pressure Torsion.

The microstructure and properties of titanium-based alloys can be tailored using severe plastic deformation. The structure and microhardness of Ti–4 wt.% Co alloy have been studied after preliminary annealing and following high pressure torsion (HPT). The Ti–4 wt.% Co alloy has been annealed at 400, 500, and 600 °C, i.e., below the temperature of eutectoid transformation in the Ti–4 wt.% Co system. The amount of Co dissolved in α-Ti increased with increasing annealing temperature. HPT led to the transformation of α-Ti in ω-Ti. After HPT, the amount of ω-phase in the sample annealed at 400 °C was about 80­85%, i.e., higher than in pure titanium (about 40%). However, with increasing temperature of pre-annealing, the portion of ω-phase decreased (60–65% at 500 °C and about 5% at 600 °C). The microhardness of all investigated samples increased with increasing temperature of pre-annealing.

Screening on binary Ti alloy with excellent mechanical property and castability for dental prosthesis application.

In the present study, the microstructure, mechanical property, castability, corrosion behavior and in vitro cytocompatibility of binary Ti–2X alloys with various alloying elements, including Ag, Bi, Ga, Ge, Hf, In, Mo, Nb, Sn and Zr, were systematically investigated, in order to assess their potential applications in dental field. The experimental results showed that all binary Ti‒2X alloys consisted entirely α–Ti phase. The tensile strength and microhardness of Ti were improved by adding alloying elements. The castability of Ti was significantly improved by separately adding 2 wt.% Bi, Ga, Hf, Mo, Nb, Sn and Zr. The corrosion resistance of Ti in both normal artificial saliva solution (AS) and extreme artificial saliva solution (ASFL, AS with 0.2 wt.% NaF and 0.3 wt.% lactic acid) has been improved by separately adding alloying elements. In addition, the extracts of studied Ti‒2X alloys produced no significant deleterious effect to both fibroblasts L929 cells and osteoblast-like MG63 cells, indicating a good in vitro cytocompatibility, at the same level as pure Ti. The combination of enhanced mechanical properties, castability, corrosion behavior, and in vitro cytocompatibility make the developed Ti‒2X alloys have great potential for future stomatological applications.

Електронна будова та мікротвердість карбідних покриттів Ti, V, Cr на сталі У10А

Електронна будова та мікротвердість карбідних покриттів Ti, V, Cr на сталі У10А

Influence of forging deformation and heat treatment on microstructure of Ti– xNb–3Zr–2Ta alloys

Ti– xNb–3Zr–2Ta alloys ( x = 33, 31, 29, 27, 25) (wt.%) were fabricated by vacuum non-consumable arc melting and hot forging. The hot-forging specimens were solid solution treated at 1053 K for 1.8 ks followed by water quenching (WQ) and air cooling (AC) respectively. The microstructure of hot-forging specimens with different deformation rate and solid solution treated at different temperatures was investigated. The result showed that a large amount of α" martensite appeared in the WQ group while only a little amount of α" phase could be found in the AC group. Moreover, for the WQ group, less niobium resulted in more diffraction peaks of α" phase in XRD profiles. This result suggested that the stability of β phase decreased with the decrease of Nb content. The microhardness of Ti– xNb–3Zr–2Ta (wt.%) alloys was improved significantly with the decreasing Nb content in both WQ group and AC group. Increasing deformation ratio could effectively refine β grains for Ti–25N–3Zr–2Ta (wt.%). Both acicular martensite and lath martensite were found in the transmission electron microscope observation of Ti–25Nb–3Zr–2Ta (wt.%) alloy. Martensitic internal twins were identified as well.

Micro-hardness, microstructures and thermal stability of (Ti,Cr,Al,Si)N films deposited by cathodic arc method

(Ti,Cr,Al,Si)N films were deposited by cathodic arc method using TiCrAlSi alloy cathodes. It was found that the microstructures of (Ti,Cr,Al,Si)N were closely related to (Al+Si) content. The crystal structure of (Ti,Cr,Al,Si)N was NaCl-type structure up to the (Al+Si) content of 0.60, where it changed to a hexagonal structure. The maximum hardness of 33 GPa was obtained at the lowest (Al+Si) content of 0.56, still in the cubic structure. The micro-hardness decreased down to 28 GPa as the crystal structure changed from NaCl-type to wurtzite-type. To investigate the thermal stabilities of (Ti,Cr,Al,Si)N, the films were annealed in a vacuum furnace. In Ti 0.20Cr 0.20Al 0.55Si 0.05N with cubic structure, the phase segregation occurred by annealing at over 900 °C, while Ti 0.22Cr 0.22Al 0.44Si 0.12N remained in cubic phase up to 1000 °C. The micro-hardness of Ti 0.20Cr 0.20Al 0.55Si 0.05N increased and that of Ti 0.22Cr 0.22Al 0.44Si 0.12N decreased at 1000 °C. Ti 0.20Cr 0.11Al 0.58Si 0.11N with a cubic and hexagonal mixture phase held its (c,h)-mixture phase up to 1000 °C, while there was an indication of an increase both in micro-hardness and in cubic ratio after annealing. In this paper, the micro-hardness and microstructure of (Ti,Cr,Al,Si)N are discussed as a function of annealing temperature and investigated by X-ray diffraction and electron microscopy.

The effect of deposition temperature and boron addition in Ti–B–C–N films deposited by plasma-enhanced chemical vapor deposition

Abstract Quaternary Ti–B–C–N films were synthesized on AISI 304 stainless steel and Si wafer by a PECVD technique using a gaseous mixture of TiCl4, BCl3, CH4, Ar, N2, and H2. The microstructure and micro-hardness of the films were largely affected by the deposition temperature and boron content. As the temperature increased from 370 °C, the micro-hardness of the film steeply increased due to the enhanced crystallinity of the film and reached to the maximum value of 42 GPa at 570 °C. However, the hardness decreased again at higher temperatures above 570 °C due to the enlarged grain size. The boron addition into Ti–C–N film resulted in the microstructural modification and our quaternary Ti–B(9 at.%)–C–N film had a fine composite microstructure consisting of nano-sized Ti(C,N) crystallites surrounded by amorphous phase of BN. The micro-hardness of Ti–B–C–N film increased from ∼21 GPa of Ti–C–N film up to ∼42 GPa of Ti–B(9 at.%)–C–N one. In this work, a systematic investigation of the microstructure and micro-hardness of Ti–B–C–N films were conducted at the deposition conditions of various temperatures and boron contents through the instrumental analyses.

Syntheses and mechanical properties of Ti–B–C–N coatings by a plasma-enhanced chemical vapor deposition

Quaternary Ti–B–C–N films were synthesized on AISI 304 and Si wafer by a PECVD technique using a gaseous mixture of TiCl 4, BCl 3, CH 4, Ar, N 2, and H 2. The microstructure of Ti–B–C–N films was characterized by instrumental analyses of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM) in this work. Our Ti–B(9 at.%)–C–N coatings had a fine composite microstructure consisting of nano-sized Ti(C,N) crystallites surrounded by amorphous BN phase. The micro-hardness of Ti–B–C–N coatings steeply increased from ∼ 21 GPa of Ti–C–N up to ∼ 42 GPa of Ti–B(9 at.%)–C–N films. In addition, Ti–B–C–N coatings showed the lowest average friction coefficient compared with other coatings of TiN, TiC, and Ti–C–N coatings prepared under the same PECVD condition. A systematic investigation of the microstructure and mechanical properties of Ti–B–C–N coatings with various boron contents is reported in this paper.

Fabrication of Ti–O/Ti–N duplex coatings on biomedical titanium alloys by metal plasma immersion ion implantation and reactive plasma nitriding/oxidation

Ti–O/Ti–N duplex coatings were fabricated on titanium alloys by metal plasma immersion ion implantation and reactive plasma nitriding/oxidation. The purpose of Ti–O is to improve the blood compatibility, and that of Ti–N is to improve the mechanical properties. X-Ray diffraction (XRD), microhardness tests, pin-on-disk wear experiments, and platelet adhesion investigation were conducted to evaluate the properties and blood compatibility of the coatings. The results reveal that the blood compatibility of the Ti–O/Ti–N duplex coatings is better than that of low temperature isotropic pyrolytic carbon (LTIC). The microhardness of Ti–O/Ti–N duplex coatings can reach 14 GPa. The wear resistance is also much better than that of Ti6Al4V alloy. The semiconductor nature of non-stoichiometric titanium oxide may be responsible for the observed improvement in the blood compatibility.

A study on the synthesis and microstructure of WC–TiN superlattice coating

WC–TiN superhard coatings are formulated to form a nanoscaled superlattice by separate arc reactive evaporation of Ti and WC. The microstructure of WC–TiN films was identified to be a superlattice of TiN and β-WC 1− x phases with modulation period (λ) of 5–13 nm and the lattice planes were continuous through the TiN and β-WC 1− x layers. The residual stress of WC–TiN films was measured to be 7.9 GPa. This high stress was reduced to 2.2 GPa by introducing Ti or Ti–WC interlayers. Ti–WC interlayer also increased the film adhesion strength. In spite of almost the same residual stress of 2.2–2.3 GPa, Ti–WC/WC–TiN film showed a higher adhesion strength of 48.5 N than that of Ti/WC–TiN film. These results are attributed to the low residual stress and higher stiffness of the Ti–WC interlayer than the soft Ti interlayer. The microhardness of Ti–WC/WC–TiN film on cemented carbide was measured to be 40 GPa and the maximum hardness was obtained as the period (λ) was approximately 7 nm. This value is approximately 1.5 times higher than that of the TiN single layer film. Other WC–TiN superlattice coatings with Ti and WC interlayers showed a hardness range of 38–40 GPa. The ratio H 3/ E 2 (plastic deformation resistance) of WC–TiN superlattice films with various interlayers was calculated to be in a range from 0.18 to 0.33. This paper reports the preparation of WC–TiN superlattice coatings on WC–Co and Si substrates using a multi-cathode arc ion-plating system. The microstructures and mechanical properties of WC–TiN superlattice films were investigated, too.

Deposition of and annealing effect on Ti(C, N) coatings

The influence of annealing environment such as temperature and atmosphere on the microhardness of Ti(C, N) coatings has been studied. Complete solid solution between TiC and TiN was obtained on steel substrates by ion plating. The composition of the coatings was close to stoichiometric. A linear relationship between the hardness and the carbon content in the coatings was obtained. The values of the Vickers hardness varied from 2100 (TiN) to 5300 (TiC) which was harder than the reported values of bulk TiC. The possible origins of such high values of the hardness are the fine grains, the crystallographic orientation, high compressive residual stresses or the dense defect-free structure of the coatings. The hardness of the TiC coatings dropped rapidly after annealing in air at 673 K although Ti(C, N) coatings maintained their hardness even at 773 K. Titanium oxide was formed at the surface of annealed samples whose values of hardness rapidly decreased. It is suggested that this softening is due to formation of soft oxides such as TiO 2 . The oxidation was dependent upon the chemical composition of the coatings. The Ti(C, N) coatings which included larger amounts of TiN component could be more oxidation resistant and maintained a very hard surface.