• Title/Summary/Keyword: Beta Ti-alloy

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Electrochemical Properties of Ti-30Ta-(3~15)Nb Alloys Coated by HA/Ti Compound Layer (HA/Ti 복합층 코팅한 Ti-30Ta-(3~15)Nb 합금의 전기화학적 특성)

  • Jeong, Yong-Hoon;Choe, Han-Cheol;Ko, Yeong-Mu
    • Journal of the Korean institute of surface engineering
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    • v.41 no.2
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    • pp.57-62
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    • 2008
  • Electrochemical properties of Ti-30Ta-$(3{\sim}15)$Nb alloys coated by HA/Ti compound layer have been studied by various electrochemical method. Ti-30Ta binary alloys contained 3, 7, 10, and 15 wt% Nb contents were manufactured by the vacuum furnace system. The specimens were homogenized for 24 hrs at $1000^{\circ}C$. The samples were cut and polished for corrosion test and coating. It was coated with HA/Ti compound layer by magnetron sputter. The HA/Ti non-coated and coated morphology of Ti alloy were analyzed by x-ray diffractometer(XRD) and filed emission scanning electron microscope(FE-SEM). The corrosion behaviors were investigated using potentiodynamic method in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The homoginazed Ti-30Ta-$(3{\sim}15wt%$)Nb alloys showed the ${\alpha}+{\beta}$ phase, and ${\beta}$ phase peak was predominantly appeared with increasing Nb content. The microstructure of Ti alloy was transformed from needle-like structure to equiaxed structure as Nb content increased. HA/Ti composite surface showed uniform coating layer with 750 nm thickness. The corrosion resistance of HA/Ti composite coated Ti-alloys were higher than those of the non-coated samples in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. Especially, corrosion resistance of Ti-Ta-Nb system increased as Nb content increased.

Microstructure and Mechanical Properties of Ti-6Al-4V Alloy Processed by Metal Injection Molding (금속분말 사출성형된 Ti-6Al-4V 합금의 미세조직 및 기계적 물성)

  • Kim, M.J.;Baek, S.H.;Yoon, D.K.;Lee, E.H.;Kim, J.H.;Ko, Y.G.
    • Transactions of Materials Processing
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    • v.29 no.5
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    • pp.251-256
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    • 2020
  • The purpose of this study is to investigate the effect of sintering condition on the microstructure evolution and tensile properties of the Ti-6Al-4V alloy sample processed by metal injection molding (MIM) in terms of the sizes of the alpha morphology and pore found in the matrix. For this purpose, a series of MIM were conducted on this sample at various sintering temperatures ranging from 1173 to 1373 K for three hours followed by furnace cooling, observed by the scanning electron microscopy. The microstructures sintered in this study showed that, with increasing sintering temperature over beta transus temperature, the transformation of the equiaxed alpha into transformed beta was attained while the size of pores would tend to decrease. Thus, the strength remained unchanged significantly in the tension while ductility increased to some extent as sintering temperature increased. Such mechanical behavior would be explained in relation to the microstructure evolution of the Ti-6Al-4V sample via the MIM.

Effect of Iron Content on Microstructure and Mechanical Properties of Ti-Mo-Fe P/M Alloys (Fe 함량에 따른 Ti-Mo-Fe 분말합금의 미세조직 및 기계적 특성 변화)

  • Hwang, HyoWoon;Lee, YongJae;Park, JiHwan;Lee, Dong-Geun
    • Journal of Powder Materials
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    • v.29 no.4
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    • pp.325-331
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    • 2022
  • Beta-titanium alloys are used in many industries due to their increased elongation resulting from their BCC structure and low modulus of elasticity. However, there are many limitations to their use due to the high cost of beta-stabilizer elements. In this study, biocompatible Ti-Mo-Fe beta titanium alloys are designed by replacing costly beta-stabilizer elements (e.g., Nb, Zr, or Ta) with inexpensive Mo and Fe elements. Additionally, Ti-Mo-Fe alloys designed with different Fe contents are fabricated using powder metallurgy. Fe is a strong, biocompatible beta-stabilizer element and a low-cost alloying element. The mechanical properties of the Ti-Mo-Fe metastable beta titanium alloys are analyzed in relation to the microstructural changes. When the Fe content increases, the tensile strength and elongation decrease due to brittle fracture despite a decreasing pore fraction. It is confirmed that the hardness and tensile strength of Ti-5Mo-2Fe P/M improve to more than 360 Hv and 900 MPa, respectively.

The Effect of the Heat Treatment Conditions on the Microstructure and Hardness of Ti-Nb Alloys (Ti-Nb계 합금의 미세조직 및 경도변화에 미치는 열처리 조건의 영향)

  • Lee, Doh-Jae;Lee, Kyung-Ku;Lee, Kwang-Min;Hwang, Ju-Young
    • Journal of Korea Foundry Society
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    • v.23 no.4
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    • pp.204-211
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    • 2003
  • Ti-3wt.%Nb(${\alpha}$type), Ti-20wt.%Nb(${\alpha}+{\beta}$,type) and Ti-40wt.%Nb(${\beta}$type) alloys were melted by vacuum are remelting. The specimens were homogenized at 1050$^{\circ}C$ for 24 hr and were then hot rolled to 50% reduction. Each alloys were solution heat treated at ${\beta}$ zone and ${\alpha}+{\beta}$, zone after homogenization, and then aged. The microstructural and hardness changes in Ti-Nb alloys with Nb contents were investigated by SEM, XRD and hardness tester. The microstructural change from equiaxied to acicular and the increase of ${\beta}$ phase in Ti-Nb alloys were obtained when the Nb content increased. The higher hardness value of ${\alpha}+{\beta}$type alloy was obtained compared to the other alloys.

A study on cytotoxicity of Ti-Nb alloys (Ti-Nb계 합금의 세포독성에 관한 연구)

  • Park, Hyo-Byeong
    • Journal of Technologic Dentistry
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    • v.25 no.1
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    • pp.89-94
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    • 2003
  • The use of titanium alloys as biomaterials is increasing due to their superior biocompatibility and enhanced corrosion resistance compared to conventional stainless steels and cobalt-based alloys. Ti-6Al-4V ($\alpha+\beta$type) alloy instead of pure titanium ($\alpha$type) is being widely used as biomaterials has some characteristics such as high fatigue strength, tensile strength and corrosion resistance. It also has similar characteristics to Ti in inducing bony ingrowth. But it has been reported recently that the vanadium element expresses cytotoxicity and carcinogenicity and the aluminium element is related with dementia of Alzheimer type and neurotoxicity. In order to overcome their detrimental effects, $\beta$-phase stabilizer Nb was chosen in the present study. CP-Ti(ASTM grade 2), Ti-3wt.%Nb($\alpha$type), Ti-20wt.%Nb ($\alpha+\beta$type) and Ti-40 wt.%Nb($\beta$type) alloys were melted by vacuum arc furnace. Biocompatibility of Ti-Nb alloys was evaluated by cytotoxicity test. The results can be summarized as follows: 1. For the cytotoxicity test, Ti-Nb alloys showed excellent biocompatibility compared to CP-Ti(ASTM grade 2), 316L STS and Co-Cr alloys.

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Microstructure and Hardness of Ti-X%Cu(X=2,5,10) Alloys for Dental Castings (치과주조용 Ti-X%Cu(X=2,5,10)합금의 미세조직 및 경도)

  • Jung, Jong-Hyun
    • Journal of Technologic Dentistry
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    • v.31 no.3
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    • pp.9-14
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    • 2009
  • This study evaluated the mechanical properties of Ti-Cu alloys with the hope of developing an alloy for dental casting with better mechanical properties than unalloyed titanium. Ti-Cu alloys with four concentrations of Cu(2,5,10wt%) were made in an argon-arc melting furnace. The microstructure and micro-Vickers hardness were determined. X-ray diffraction pattern test was performed on the polished specimens. The microstructure of 2%Cu and 5%Cu alloys are shown acicular ${\alpha}Ti$ phase formed on the surfaces of previously formed $\beta$grains. The 10%Cu alloys has essentially a eutectoid structure; this structure includes lamella of ${\alpha}Ti$ and $Ti_2Cu$ phase that transformed from ${\alpha}Ti$ at the eutectoid temperature. The micro-Vickers hardness of CP Ti specimens was significantly(p<0.05) lower than that of any of the other alloys. Among the Ti-Cu alloys, the 10%Cu alloys exhibited a significantly(p<0.05) higher hardness value. but lower than that of Ti-6%Al-4%V alloy. From these results, it was concluded that new alloys for dental castings should be designed as Ti-Cu based alloys if other properties necessary for dental castings were obtained.

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Microstructure and Corrosion Resistance of Ti-15Sn-4Nb Alloy with Hf Adding Element (Hf가 첨가된 생체용 Ti-15Sn-4Nb 합금의 미세조직 및 내식성)

  • Lee, Doh-Jae;Lee, Kyung-Ku;Cho, Kyu-Zong;Yoon, Taek-Rim;Park, Hyo-Byung
    • Journal of Technologic Dentistry
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    • v.23 no.1
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    • pp.55-64
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    • 2001
  • This study is focusing on the improvement of problems of Ti-6Al-4V alloy. A new Ti based alloy, Ti-15Sn-4Nb, have designed to examine any possibility of improving the mechanical properties and biocompatibility. Specimens of Ti alloys were melted in vacuum arc furnace and homogenized at $100^{\circ}C$ for 24h. All specimens were solution treated at $812^{\circ}C$ and aged at $500^{\circ}C$ for 10h. The corrosion resistance of Ti alloys was evaluated by potentiodynamic polarization test and immersion test inl%Lactic acid solutions. Ti-15Sn-4Nb system alloys showed Widmanstatten microstructure after solution treatment which is typical microstructure of ${\alpha}+{\beta}$ type Ti alloys. Analysing the corrosion resistance of Ti alloys, it was concluded that the passive films of Ti-15Sn-4Nb system alloys are more stable than that of Ti-6Al-4V alloys. Also, the corrosion resistance of Ti-15Sn-4Nb system alloys was improved with adding elements, Hf. It was analysed that the passive film of the Ti-15Sn-4Nb alloy which was formed in air atmosphere was consisted of TiO2, SnO and NbO through X-ray photoelectron spectroscopy(XPS) analysis.

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A Study on Microstructure and Mechanical Properties of Hf, Ta Added Ti-l5Sn-4Nb system Alloys for Biomaterial (Hf, Ta가 첨가된 Ti-l5Sn-4Nb계 생체용 합금의 미세조직 및 기계적 성질에 관한 연구)

  • 김대환;이경구;박효병;이도재
    • Journal of the Korean institute of surface engineering
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    • v.33 no.4
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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.

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Change of Compressive Deformation Behaviors of Ti-5Mo-xFe Metastable Beta Alloy According to Fe Contents (Fe 함량에 따른 Ti-5Mo-xFe 준안정 베타 합금의 압축 변형거동 변화)

  • Yong-Jae Lee;Jae Gwan Lee;Dong-Geun Lee
    • Journal of the Korean Society for Heat Treatment
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    • v.36 no.5
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    • pp.303-310
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    • 2023
  • β titanium alloys are widely used in aerospace industry due to their excellent specific strength and corrosion resistance. In particular, mechanical properties of metastable β titanium can efficiently be controlled by various deformation mechanisms such as slip, twinning, and SIM (Stress-Induced Martensite Transformation), making it an ideal material for many industrial applications. In this study, Ti-5Mo-xFe (x=1, 2, 4 wt%) alloy was designed by adding a relatively inexpensive β element to ensure price competitiveness. Additionally, microstructural analysis was conducted using OM, SEM, and XRD, while mechanical properties were evaluated through hardness and compression tests to consider the deformation mechanisms based on the Fe content. SIMT occurred in all three alloys and was influenced by the presence of βm (metastable beta) and beta stability. As the Fe content decreased, the α'' phase increased due to SIMT occurring within the βm phase, resulting in softening. Conversely, as the Fe content increased, the strength of the alloy increased due to a reduction in α'' formation and the contributions of solid solution strengthening and grain strengthening. Moreover, unlike the other alloys, shear bands were observed only in the fracture of the Ti-5Mo-4Fe alloy, which was attributed to differences in texture and microstructure.