• Title/Summary/Keyword: Beta Ti-alloy

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Characteristics of Brazing of Eyewear Frame Ti Alloy with Electric Resistance (전기저항을 이용한 안경테용 Ti 합금의 땜질 특성)

  • Park, Jeong-Sik;Lee, Jeong-Yeong
    • Journal of Korean Ophthalmic Optics Society
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    • v.12 no.4
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    • pp.15-18
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    • 2007
  • Titanum and its alloys have been used as the important materials of eyewear frame because of its light weight, mechanical strength and corrosion resistance. This study investigated the characteristics of P-Ti and ${\beta}$-Ti alloys in accordance with joining conditions by electric resistance brazing. Hardness of P-Ti and ${\beta}$-Ti has been reduced because of an increase of grain size by the growth of brazing time. Hardness reduction and reduction area by grain growth were largely appeared in P-Ti than ${\beta}$-Ti.

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Evolution on Microstructure and Mechanical Property of Ti65Fe35 Hypereutectic Alloys by Adding Low Melting Temperature Elements (저융점 원소의 첨가에 따른 Ti65Fe35 과공정 합금의 미세구조와 기계적 특성의 변화)

  • Hwang, Yun Jung;Hong, Sung Hwan;Kim, Jeong Tae;Kim, Young Seok;Park, Hae Jin;Kim, Hee Jin;Jeong, Yeon Beom;Lee, Young Hoon;Kim, Ki Buem
    • Korean Journal of Materials Research
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    • v.27 no.10
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    • pp.557-562
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    • 2017
  • The microstructural evolution and modulation of mechanical properties were investigated for a $Ti_{65}Fe_{35}$ hypereutectic alloy by addition of $Bi_{53}In_{47}$ eutectic alloys. The microstructure of these alloys changed with the additional BiIn elements from a typical dendrite-eutectic composite to a bimodal eutectic structure with primary dendrite phases. In particular, the primary dendrite phase changed from a TiFe intermetallic compound into a ${\beta}$-Ti solid solution despite their higher Fe content. Compressive tests at room temperature demonstrated that the yield strength slightly decreased but the plasticity evidently increased with an increasing Bi-In content, which led to the formation of a bimodal eutectic structure (${\beta}$-Ti/TiFe + ${\beta}$-Ti/BiIn containing phase). Furthermore, the (Ti65Fe35)95(Bi53In47)5 alloy exhibited optimized mechanical properties with high strength (1319MPa) and reasonable plasticity (14.2 %). The results of this study indicate that the transition of the eutectic structure, the type of primary phases and the supersaturation in the ${\beta}$-Ti phase are crucial factors for controlling the mechanical properties of the ultrafine dendrite-eutectic composites.

Effect of V on High Temperature Oxidation of TiAl Alloy (TiAl합금의 고온산화에 미치는 V효과)

  • ;Morihiko Nakamura
    • Journal of the Korean institute of surface engineering
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    • v.36 no.4
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    • pp.329-333
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    • 2003
  • The high-temperature oxidation behavior of Ti39Al-10V alloy that consisted primarily of $\beta$-Ti, ${\gamma}$-TiAl, and $\alpha_2$ $-Ti_3$Al phases was studied. The relatively thick and porous oxide scales formed consisted primarily of an outermost, thin TiO$_2$ layer, and an outer, thin $Al_2$$O_3$-rich layer, and an inner, very thick (TiO$_2$, $Al_2$$O_3$) mixed layer. Vanadium was present uniformly throughout the oxide scale. The formation and subsequent evaporation of V-oxides such as VO, $VO_2$, and $V_2$O$_{5}$ deteriorated oxidation resistance and scale adherence of the TiAl alloy significantly.y.

EFFECT OF ELECTROLYTE CONCENTRATION ON THE SURFACE CHARACTERISTICS OF ANODIZED AND HYDROTHERMALLY-TREATED TI-6AL-7NB ALLOY (전해질 농도가 양극산화와 열수처리한 Ti-6Al-7Nb 합금의 표면 특성에 미치는 영향)

  • Jang Tae-Yeob;Song Kwang-Yeob;Bae Tae-Sung
    • The Journal of Korean Academy of Prosthodontics
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    • v.43 no.5
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    • pp.684-693
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    • 2005
  • Statement of problem: Ti-6Al-7Nb alloy is used instead of Ti-6Al-4V alloy that was known to have toxicity. Purpose: This study was performed to investigate the effect of electrolyte concentration on the surface characteristics of anodized and hydrothermally-treated Ti-6Al-7Nb alloy Materials and methods: Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1,000 SiC paper ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed at current density $30mA/cm^2$ up to 300 V in electrolyte solutions containing $\beta-glycerophosphate$ disodium salt hydrate $(\beta-GP)$ and calcium acetate (CA). Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. All samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 30 days. Results and conclusion: The results obtained were summarized as follows: 1. After hydrothermal treatment, the precipitated HA crystals showed the dense fine needle shape. However, with increasing the concentration of electrolyte they showed the shape of thick and short rod. 2. When the dense fine needle shape crystals was appeared after hydrothermal treatment, the precipitation of HA crystals in Hanks' solution was highly accelerated. 3. The crystal structures of $TiO_2$ in anodic oxide film were composed of strong anatase peak and weak rutile peak as analyzed with thin-film X-ray diffractometery. 4. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal in Hanks' solution.

A Study on the Mechanical Properties of Ti-8Ta-3Nb Alloy for Biomaterials

  • Lee, Kyung-Won;Ban, Jae-Sam;Yu, Yeong-Seon;Cho, Kyu-Zong
    • Journal of Mechanical Science and Technology
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    • v.18 no.12
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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$^{\circ}C$.

Electrochemical Characteristics of Osteoblast Cultured Ti-Ta Alloy for Dental Implant (골아세포가 배양된 치과 임플란트용 Ti-Ta합금의 전기화학적 특성)

  • Kim, W.G.;Choe, H.C.;Ko, Y.M.
    • Journal of the Korean institute of surface engineering
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    • v.41 no.2
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    • pp.69-75
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    • 2008
  • Electrochemical behaviors of surface modified and MC3T3-E1 cell cultured Ti-30Ta alloys have been investigated using various electrochemical methods. The Ti alloys containing Ta were melted by using a vacuum furnace and then homogenized for 6 hrs at $1000^{\circ}C$. MC3T3-E1 cell culture was performed with MC3T3-E1 mouse osteoblasts for 2 days. The microstructures and corrosion resistance were measured using FE-SEM, XRD, EIS and potentiodynamic test in artificial saliva solution at $36.5{\pm}1^{\circ}C$. Ti-Ta alloy showed the martensite structure of ${\alpha}+{\beta}$ phase and micro-structure was changed from lamellar structure to needle-like structure as Ta content increased. Corrosion resistance increased as Ta content increased. Corrosion resistance of cell cultured Ti-Ta alloy increased predominantly in compared with non cell cultured Ti- Ta alloy due to inhibition of the dissolution of metal ion by covered cell. $R_p$ value of MC3T3-E1 cell cultured Ti-40 Ta alloy showed $1.60{\times}10^6{\Omega}cm^2$ which was higher than those of other Ti alloy. Polarization resistance of cell-cultured Ti-Ta alloy increased in compared with non-cell cultured Ti alloy.

Recent R&D status on friction stir welding of Ti and its alloys (티타늄과 그 합금의 마찰교반용접기술 현황)

  • Kang, Duck-Soo;Lee, Kwang-Jin
    • Journal of Welding and Joining
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    • v.33 no.2
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    • pp.1-7
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    • 2015
  • This article describes the basic technical concepts for applying the friction stir welding (FSW) process to titanium and its alloys. Titanium and its alloys are demanding applications of FSW. During FSW, a protective atmosphere is needed at the welding region to prevent the joints from oxidation due to the absorption of interstitial elements (O, N, and H) at high temperature. The process parameters for FSW have great influence on the microstructure and properties of the joints. No phase transformation occurred in CP Ti because FSW was achieved below the ${\beta}$-transus temperature. Therefore, the mechanical properties of the joints with CP Ti were governed by recrystallization and grain refinement. Furthermore, the strong crystallographic texture indicating <0001>//ND formed in the stir zone. On the other hands, the phase transformation occurred in Ti-6Al-4V alloy because the process temperature reached above ${\beta}$-transus temperature. For this reason, the mechanical properties of the joints with Ti-6Al-4V alloy were altered by not only recry stallization and grain refinement but also phase transformation during FSW. Engineers who want to get sound FSW joints with Ti-6Al-4V alloy have to pay attention to the control about process conditions.

Study on the thermal-property of Ti-10Ta-10Nb (생체재료용 Ti-10Ta-10Nb 합금의 열적 특성 고찰)

  • 반재삼;이경원;정상원;유영선;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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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$^{-1}$

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Effects of Niobium Addition on the Corrosion Behavior of Ti Alloys in NaCl Solution (NaCl 용액에서 Nb 첨가가 Ti 합금의 부식 거동에 미치는 영향)

  • Kim, E.S.;Kim, W.G.;Choe, H.C.
    • Corrosion Science and Technology
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    • v.12 no.1
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    • pp.34-39
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    • 2013
  • In this study, the effect of niobium addition on the passivation behavior of Ti alloys in NaCl solution was investigated using various electrochemical methods. An ${\alpha}$-phase in Ti alloy was transformed into a ${\beta}$-phase and martensite structure decreased as Nb content increased. The corrosion and passivation current density($+300mV_{SCE}$) decreased as Nb content increased, and thereby a stable passive film was formed on the Ti alloy. Potential of Ti-xNb alloy in the passive region increased, whereas, current density decreased with time from results of potentiostatic and galvanostatic tests. Also, the corrosion morphology showed the smaller pits as Nb content increased. Consequently, Ti alloy contained high Nb content showed a good resistance to pitting corrosion in 0.9% NaCl solution.

Electrochemical Characteristics of HA Film on the Ti Alloy Using Pulsed Laser Deposition

  • Jeong, Yong-Hoon;Shin, Seung-Pyo;Chung, Chae-Heon;Kim, Sang-Sub;Choe, Han-Cheol
    • Korean Journal of Metals and Materials
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    • v.50 no.5
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    • pp.395-400
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    • 2012
  • In this study, we have investigated the surface morphology of hydroxyapatite (HA) coated Ti alloy surface using pulsed laser plating. The HA (tooth ash) films were grown by pulsed KrF excimer laser, film surfaces were analyzed for topology, chemical composition, crystal structure and electrochemical behavior. The Ti-6Al-4V alloy showed ${\alpha}$ and ${\beta}$ phase, Cp-Ti showed ${\alpha}$ phase and the HA coated surface showed HA and Ti alloy peaks. The HA coating layer was formed with $1-2{\mu}m$ droplets and grain-like particles, particles which were smaller than the HA target particle, and the composition of the HA coatings were composed of Ca and P. From the electrochemical test, the pitting potential (1580 mV) of HA coated Ti-6Al-4V alloy was higher than those of Cp-Ti (1060 mV) and HA coated Cp-Ti (1350 mV). The HA coated samples showed a lower current density than non-HA coated samples, whereas, the polarization resistance of HA coated samples showed a high value compared to non-HA coated samples.