• 한국재료학회지
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• 제8권4호
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• pp.304-311
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• 1998

0.07%C-0.014%Ti-0.015Nb-0.005%B강 (강종 B)을 각각 TMCP처리하여 그 기계적 특성과 B의 거동을 조사하였다. Ta-B강이 Ti-Nb-B강보다 인장강도는 더 우수하였으나 충격 흡수에너지는 훨씬 더 낮았다. Ta-B강의 강도가 Ti-Nb-B강보다 더 우수한 이유는 Ta-B강에서의 Ta의 석출강화 효과가 Ti-Nb-B강에서의 Ti와 Nb의 석출강화 효과보다 더 크기 때문으로 생각된다. Ta-B강은 입내파괴, Ti-Nb-B강은 임계파괴의 파괴양상을 보여이며, Ti-Nb-B강이 Ta-B 강보다 더 큰 충격 흡수에너지를 나타내었다. TMCP에서는 항온변태시의 평형석출과는 달리 연속냉각방법을 사용하였기 때문에 B가 결정립계에 평형적 또는 비평형적으로 편석되어 준안정상으로 생각되는 연속적인 필름 형태의 붕화물을 형성한다. 또한, 냉각속도의 차이에 따라 석출물은 결정질이 되거자 비정질이 되었다. B의 함량이 많은 Ti-Nb-B강에서는 석출물이 비정질상이었다. 한편, B함량이 적은 Ta-B강에서는 B강에서는 결정립계에서 B가 관찰되지 않아는데, 이것은 결정립계에서의 B의 석출이 B의 함량에 매우 민감함을 의미하는 것이다.

• 한국표면공학회지
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• 제33권4호
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• pp.251-260
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• 2000

Ta and Hf added Ti-l5Sn-4Nb alloys without V and Al elements for biomaterial were melted by arc furnace in response to recent concerns about the long term safety of Ti-6Al-4V alloy. All specimens were homogenized at $1000^{\circ}C$ and solution treatment was performed at $812^{\circ}C$ and aging treatment at $500^{\circ}C$. The microstructure and mechanical properties were analysed by optical micrograph, hardness tester and instron. Ti-l5Sn-4Nb system alloys showed widmanstatten microstructure which is typical microstructure in $\alpha$＋$\beta$ type Ti alloys. The Ti-l5Sn-4Nb-2Hf and Ti-l5Sn-4Nb-2Ta alloys showed better hardness and tensile strength compared with Ti-6Al-4V. The result of XPS analysis, Ti-l5Sn-4Nb alloy in air atmosphere consisted of $TiO_2$, SnO and NbO.

• 한국재료학회지
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• 제14권3호
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• pp.211-217
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• 2004

The oxidation behaviors of Ti-10Ta-10Nb alloy and Ti-6Al-4V alloy were studied in dry air atmosphere. Specimens were melted in consumable vacuum arc furnace and homogenized at $1050^{\circ}C$ for 24 h. Hot rolling was performed at $1000^{\circ}C$. Specimens of the alloys were oxidized as the temperature range $400~650^{\circ}C$ for 30 min. The oxidation behavior of the alloys was analysed by optical microscope, SEM/EDX, XRD, XPS and TGA. Immersion test was performed in 1% Lactic acid. In the microscope observation, oxide layer of Ti-10Ta-10Nb alloy was denser and thinner than Ti-6Al-4V's. The weight gains during the oxidation rapidly increased at the temperature above $600^{\circ}C$ in Ti-6Al-4V's alloy and$ 700^{\circ}C$ in Ti-10Ta-10Nb alloy. According to XRD results, oxide layers were composed of mostly $TiO_2$(rutile) phase. It was analysed that the passive film of the Ti alloys consisted of $TiO_2$ through X-ray photoelectron spectroscopy(XPS) analysis.

• 대한치과기공학회지
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• 제27권1호
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• pp.19-25
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• 2005

Ti6Al4V alloy have been mainly used as implant materials. Ti-6Al-4V alloy instead of pure Ti is being widely used as biomaterials has some characteristics such as high fatigue strength, tensile strength. But it has been reported recently that vanadium component expresses cytotoxicity and carcinogenicity and aluminium component is related with dementia of Alzheimer type. In order to overcome their detrimental effects, $\beta$-phase stabilizer Nb was chosen in the present study, in addition Ta and Hf were added to Ti-40wt.%Nb alloy to improve its mechanical properties. This paper was described the influence of heat treatment of Ti-40Nb alloys with 2wt%Ta, 2wt%Hf on the mechanical properties. Specimens of Ti alloys were melted in vacuum arc furnace and homogenized at 1050$^{\circ}C$ for 24 hr. and then were aged after solution heat treat at $\alpha+\beta$ and $\beta$ regions. The mechanical properties of Ti alloys were analysed by hardness test, tensile test, elongation test and SEM test. The results can be summarized as follows: 1. The mechanical properties Ti-40wt.%Nb were improved when 2wt.% Ta and 2wt.%Hf were added. 2. The higher tensile strength value and elongation at solution heat treat was higher than solution heat treat and then were aged.

• 한국표면공학회지
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• 제39권1호
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• pp.43-48
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• 2006

The oxidation behavior and Biocompatibility of pure Ti and Ti-8Ta-3Nb alloy were studied in dry air atmosphere. The specimens showed that Ti-8Ta-3Nb alloy had higher oxidation resistance than pure Ti at $650^{\circ}C$. Cytotoxicity test also revealed that moderate oxidation treatment lower cell toxicity and Ti-8Ta-3Nb alloy showed better results compared with pure Ti. The weight gains during the oxidation increase rapidly at temperature above $600^{\circ}C$.

• 한국세라믹학회지
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• 제32권5호
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• pp.582-586
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• 1995

The crystal structures of (Na0.3Sr0.7)(Ti0.7M0.3)O3 (M=Ta, Nb) compounds were determined using the Rietveld method. Due to the tilting of a oxygen octahedron, (Na0.3Sr0.7)(Ti0.7Nb0.3)O3 had a superlattice of doubled a, b and c of simple perovskite. The crystal structure of (Na0.3Sr0.7)(Ti0.7M0.3)O3 was tetragonal with a space group 14/mmm. The crystal structure of (Na0.3Sr0.7)(Ti0.7M0.3)O3 was a cubic with space group Pm3m, in which no tilting of oxygen octahedron was observed. The difference in the oxygen tilting of these two materials was due to the larger covalency of Nb-O bond than that of Ta-O bond, which induced a strong $\pi$Nb0 bonding in (Na0.3Sr0.7)(Ti0.7M0.3)O3. Therefore, the higher transition temperature of (Na0.3Sr0.7)(Ti0.7M0.3)O3 could be related to the larger tilting of oxygen octahedron.

• Archives of Metallurgy and Materials
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• 제65권4호
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• pp.1311-1315
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• 2020

This study investigates the microstructures and the mechanical properties of equiatomic Ti₂₀Mo₂₀Ta₂₀Nb₂₀V₂₀ and non-equiatomic Ti₄₀Mo₁₅Ta₁₅Nb₁₅V₁₅ and Ti₆₀Mo₁₀Ta₁₀Nb₁₀V₁₀ HEAs using X-ray diffraction (XRD) analysis, field emission scanning electron microscope (FE-SEM), and micro-Vickers hardness test. The specimens were fabricated using the vacuum arc remelting (VAR) process and homogenized at a temperature of 1300℃ for 4 h in a vacuum atmosphere. The determined thermodynamic parameters, Ω ≥ 1.1, δ ≤ 6.6%, and VEC < 6.87, suggested that the HEAs consisted of BCC solid solutions. XRD patterns of all the HEAs displayed single BCC phases. The difference in the solidification rate led to the micro-segregation associated with the elements Ta and Mo enriched in the dendrite arms and the elements V and Ti in the inter-dendritic regions. The HEA specimens showed a decrease in hardness with higher concentration of Ti element because the intrinsic hardness of Ti is lower as compared to the intrinsic hardness of Nb and Mo.

• 대한치과기공학회지
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• 제26권1호
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• pp.97-104
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• 2004

A new Ti-10Ta-10Nb alloy has designed and examined some possibility of forming more passive oxide film by oxidation treatment which is closely related to corrosion resistance and biocompatibility. Ti-6Al-4V and Ti-10Ta-10Nb alloys were prepared by consumable vacuum arc melting and homogenized at 1050$^{\circ}C$ for 24hours. Alloy specimens were oxidized at the temperature range of 400 to 750$^{\circ}C$ for 30minutes, and the oxide films on Ti alloys were analysed by optical microscope, SEM, XPS and TGA. Cytotoxicity test was performed in MTT assay treated L929 fibroblast cell culture by indirect method. It is found out that the oxide film on Ti-10Ta-10Nb alloy is denser and thinner compared to Ti-6Al-4V alloy. The weight gain during the oxidation was increased rapidly at the temperature above 650$^{\circ}C$ for Ti-6Al-4V alloy and above 700$^{\circ}C$ for Ti-10Ta-10Nb alloy respectively. It was analysed that the passive film of the Ti alloys consisted of TiO2 through X-ray photoelectron spectroscopy (XPS) analysis. It is found out by cytotoxicity test that moderate oxidation treatment lowers cell toxicity, and Ti-10Ta-10Nb alloy showed better result compared to Ti-6Al-4V alloy.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2204-2208
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• 2004

Ti-8Ta-3Nb has been developed as a new biomaterial. The experimental specimens are as-cast and forged Ti-8Ta-3Nb alloys. Treatment in a solution, ranging from 760 to 960$^{\circ}C$ has carried out. The microstructural research has carried out after the solution treatment and the hardness was measured. The specific heat and the length variations of Ti-8Ta-3Nb were also measured. The optimum temperature for the solution heat treatment of Ti-8Ta-3Nb was found to be 880$^{\circ}C$. This was based on the mechanical properties and the volume fraction of ${\alpha}$ phase and their phases shown from the results of the solution heat treatment. From the results, the ${\beta}$ transition temperature of Ti-8Ta-3Nb was found to be between 860$^{\circ}C$ and 880$^{\circ}C$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1370-1373
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• 2003

Specimens of Ti-10Ta-10Nb have been tested for Rockwall hardness after heating to either the $\alpha$+$\beta$ and $\beta$-phase field. And the specific heat and the dilatometer of Ti-10Ta-103Nb swaged have been measured. From the result, the $\beta$ transus of the alloy was determined to be 82$0^{\circ}C$. The hot deformation behavior of Ti-10Ta-10Nb with an $\alpha$+$\beta$ microstructure is modeled in the temperature 75$0^{\circ}C$ and strain rate range 0.001-10$^{-1}$