• Title/Summary/Keyword: Beta Ti-alloy

Search Result 115, Processing Time 0.023 seconds

Study on the mechanical Properties of Ti-8Ta-3Nb Alloys for Biomaterials (생체재료용 Ti-8Ta-3Nb 합금의 물성변화 고찰)

  • 이경원;반재삼;유영선;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2003.06a
    • /
    • pp.1374-1377
    • /
    • 2003
  • Ti-8Ta-3Nb is made for biomaterial. The experimental speciments are as-cast Ti-8Ta-3Nb and Ti-8Ta-3Nb swaged. The solution treatment in the range 760-96$0^{\circ}C$have been carried out. The microstructural investigations have been carried out on the specimens after the solution treatment. and the hardness have been measured. And the specific heat and the dilatometer of Ti-8Ta-3Nb swaged have been measured. From the result, the $\beta$ transus of the alloy was determined to be 880-86$0^{\circ}C$.

  • PDF

Characterization of Hot Deformation Behavior of Ti-6Al-4V Alloy (Ti-6Al-4V 합금의 고온변형거동 규명)

  • 염종택;김두현;나영상;박노광
    • Transactions of Materials Processing
    • /
    • v.10 no.4
    • /
    • pp.347-354
    • /
    • 2001
  • Compression tests were carried out to investigate the hot-deformation behavior of Ti-6Al-4V alloy in the temperature range of $915^{\circ}C$ to $1015^{\circ}C$ and the strain rate range of $10^{-3}s^{-i}$ to $10s^{-1}$. Under the given test conditions, the hot-deformation of Ti-6Al-4V alloy was mainly led by dynamic recovery rather than by dynamic recrystallization. The activation energy for the plastic deformation in $\alpha+\beta$ field was about 894 kJ/mol and $\beta$ field was 332kJ/mo1. Processing map for hot working are developed on the basis of the variations of efficiency of power dissipation($\eta$=2m/m+1) and flow instability criterion using the dynamic material model. The optimum process condition in the ($\alpha+\beta$) field was obtained at the temperature ranges of $930^{\circ}C$ to $955^{\circ}C$$^{\circ}C$ and a strain rate of $10^{-3}s{-1}$.

  • PDF

A study on corrosion resistance of Ti-Nb alloys by Nb contents (Nb 함량에 따른 Ti-Nb계 합금의 내식성에 대한 연구)

  • Park, Geun-Hyeung
    • Journal of Technologic Dentistry
    • /
    • v.28 no.1
    • /
    • pp.61-66
    • /
    • 2006
  • Titanium alloys have been used for dental materials due to it's very good biocompatibility. Ti-6Al-4V alloy instead of pure titanium is being widely used as biomaterials has some characteristics such as high fatigue strength, tensile strength and corrosion resistance. 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. The Ti-Nb alloys has designed and examined corrosion resistance. Ti-3wt.%Nb($\alpha$type), Ti-20wt.%Nb(${\alpha}+{\beta}$type) and Ti-40wt.%Nb($\beta$type) alloys were melted by vacuum arc furnace. The corrosion resistance of Ti alloys was evaluated by potentiodynamic polarization test in the solution of 0.9% NaCl and 5% HCl. The results can be summarized as follows: 1) For the corrosion test in the solution of 0.9% NaCl and 5% HCl, the corrosion behaviour of Ti-Nb alloys was similar to ASTM grade 2 CP Ti. 2) The corrosion resistance of Ti-20Nb alloy was better than that of CP-Ti, Ti-3Nb, Ti-40Nb alloy in 0.9% NaCl and 5% HCl, solutions.

  • PDF

Corrosion Characteristics of Ti-xTa Alloys with Ta contents (Ta 함량에 따른 Ti-xTa 합금의 부식특성)

  • Kim, H.J.;Choe, H.C.
    • Corrosion Science and Technology
    • /
    • v.12 no.1
    • /
    • pp.50-55
    • /
    • 2013
  • The purpose of this study was to investigate corrosion characteristics of Ti-xTa alloys with Ta contents. Ti-xTa alloys used as samples (x=30, 40%) were arc-melted under argon atmosphere of 99.9% purity. Ti-xTa alloys were homogenized for 12hr at $1000^{\circ}C$ and then water quenched. The surface characteristics of Ti-xTa alloys were investigated using optical microscopy (OM) and X-ray diffractometer (XRD). The anodic corrosion behaviors of the specimens were examined through potentiodynamic, potentiostatic and galvanostatic test in 0.9 % NaCl solution at $36.5{\pm}1^{\circ}C$. After corrosion test, the surface characteristics of Ti-xTa alloys were investigated using OM. The microstructure of Ti-Ta alloy showed the beta structure with Ta content. The corrosion resistance of Ti alloy was improved by increasing Ta content and the corrosion morphology of Ti-Ta alloy showed that the site attacked by chloride ion decreased from the active to passive region with Ta content. Potential of Ti-40Ta alloy increased as time increased, whereas, current density of Ti-40Ta alloy decreased as time increased compared to Ti-30 alloy.

High Temperature Compressive Deformation Behavior of Ti-6Al-2Sn-4Zr-6Mo Alloy (Ti-6Al-2Sn-4Zr-6Mo 합금의 고온압축 변형거동)

  • Hyun, Yong-Taek;Lee, Yong-Tai;Lee, Chan-Gyu
    • Korean Journal of Materials Research
    • /
    • v.11 no.2
    • /
    • pp.82-87
    • /
    • 2001
  • The hot deformation behavior of Ti-6Al-2Sn-4Zr-6Mo(Ti6246) alloy was investigated in both the $\alpha$+$\beta$ and $\beta$-phase fields by conducting compression tests over a strain rate range of $10^{-3}s^{-1}$ to $10^0s^{-1}$. The flow stress was increased with increasing strain rate and decreasing test temperature. The flow curves obtained at temperatures below 90$0^{\circ}C$ exhibited a flow softening. However, in the $\beta$-phase field, above 95$0^{\circ}C$, the flow stress increased monotonically with plastic strain approaching steady state values. Constitutive equations for the dependence of flow stress on strain, strain rate, and temperature were developed through the analysis of the flow curves.

  • PDF

Formation of submicrocrystalline in Ti-13Nb-13Zr alloy without severe deformation and enhanced mechanical compatibility (Ti-13Nb-13Zr 합금의 저 변형량에서 초미세 결정립 형성 및 기계적 적합성 향상)

  • Park, C.H.;Yeom, J.T.;Chun, Y.S.;Lee, C.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2009.10a
    • /
    • pp.328-331
    • /
    • 2009
  • Microstructural evolution of alpha and beta phases during dynamic globularization of near-beta Ti-13Nb-13Zr alloy was investigated to determine the optimum processing conditions. The submicrocrystalline alloy sheet with ${\sim}80%$ of high-angle grain boundaries was produced utilizing dynamic globularization at temperature of $600^{\circ}C$, equivalent strain rate of $10^{-1}\;s^{-1}$ and strain of 1.4. The refined structure with the gain size of ${\sim}0.4{\mu}m$ showed 25-60% enhanced mechanical compatibility as compared to those of the conventional mill-annealed or solution treated and aged microstructures.

  • PDF

Microstructure and Mechanical Properties of Ti-35Nb-7Zr-XCPP Biomaterials Fabricated by Rapid Sintering

  • Woo, Kee-Do;Park, Sang-Hoon;Kim, Ji-Young;Kim, Sang-Mi;Lee, Min-Ho
    • Korean Journal of Materials Research
    • /
    • v.22 no.3
    • /
    • pp.150-154
    • /
    • 2012
  • Ti-6Al-4V ELI (Extra Low Interstitial) alloy have been widely used as alternative to bone due to its excellent biocompatibility, although it still has many problems such as high elastic modulus and toxicity. Therefore, biomaterials with low elastic modulus and non toxic characteristics have to be developed. A novel ${\beta}$ Ti-35wt%Nb-7wt%Zr-Calcium pyrophosphate (CPP) composite that is a biocompatible alloy without elemental Al or V was fabricated by spark plasma sintering (SPS) at $1000^{\circ}C$ under 70 MPa using high energy mechanical milled (HEMM) powder. The microstructure and phases of the milled powders and the sintered specimens were studied using SEM, TEM, and XRD. Ti-35wt%Nb-7wt%Zr alloy was transformed from ${\alpha}$ phase to ${\beta}$ phase in the 4h-milled powder by sintering. The sintered specimen using the 4h-milled powder showed that all the elements were distributed very homogeneously and had higher density and hardness. ${\beta}$ Ti alloy-CPP composite, which has nanometer particles, was fabricated by SPS using HEMMed powder. During the sintering process, $CaTiO_3$, TixOy, and CaO were formed because of the reaction between Ti and CPP. The Vickers hardness of the composites increases with the increase of the milling time and the addition of CPP. The biocompatibility of the Ti-Nb-Zr alloys was improved by addition of CPP.

The Characteristics of Ultrasonic Signals for Detecting Micro-Defects in Ti-6Al-4V Alloy (Ti-6Al-4V 합금의 내부 미소결함에 따른 초음파 신호 특성 연구)

  • Choi, Sang-Woo;Lee, Joon-Hyun;Kubota, M.;Murakami, Y.
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.21 no.6
    • /
    • pp.591-597
    • /
    • 2001
  • Ti alloy is used for essential parts of aircraft for high temperature environment. Although Ti alloy has excellent performance in regard to mechanical properties, it is difficult ot find fatigue cracks by nondestructive ultrasonic inspection due to its two-phase microstructure, which consists of hard alpha and beta phases. Sound energy reflected from microstructural features in the component produces a background inspection noise which is seen even when no defects are present. This noise can inhibit the detection of critical internal defects such as pores cracks or inclusions. To obtain fundamental data on ultrasonic inspection of Ti alloy, ultrasonic testing was performed using a specimen with small drill holes and ultrasonic wave propagation velocites were measured.

  • PDF

Study on High Temperature Phase Transformation and Directional Solidification of TiAl-Nb Alloy (TiAl-Nb 합금의 고온상변태와 일방향응고에 관한 연구)

  • Park, Jong-Moon;Jang, Ho-Seung;Kim, Seong-Woong;Kim, Seung-Eon;Shon, Je-Ha;Oh, Myung-Hoon
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.29 no.5
    • /
    • pp.227-233
    • /
    • 2016
  • Phase transformation phenomenon at high temperature was investigated by using designed TiAl-Nb alloys with addition of the ${\beta}$ stabilizer. Examination of dendritic morphologies in arc-melted button ingot could reveal the crystallography of the primary solidification phase. It was found that the addition of ${\beta}$ stabilizer(Nb) shifted the high temperature region of the binary Ti-Al phase diagram to the high Al composition side so that ${\beta}$ phase forms as a primary crystal even at higher Al composition compared with the binary Ti-Al system. The ${\beta}$ was found to be the primary solidification phase for alloys with Al content less than about 52 at.%. The composition of ${\beta}$ solidification in Ti-Al-Nb ternary system could be determined from the partial liquidus projection which was constructed by observing the microstructure of arc-melted buttons. The Ti-46Al-(6, 8)Nb composition was selected for ${\beta}$ solidification and the directional solidification was performed by a floating zone-type DS apparatus at the growth rate 30 mm/hr respectively.

MECHANICAL PROPERTIES AND CORROSION BEHAVIORS OF AGED Ti-4Mo-4Cr-X (X = Sn, V, Zr) ALLOYS FOR METALLIC BIOMATERIALS

  • KWANGMIN LEE;GUNHEE LEE
    • Archives of Metallurgy and Materials
    • /
    • v.65 no.4
    • /
    • pp.1297-1301
    • /
    • 2020
  • The purpose of this study was to investigate the mechanical properties of beta type aged Ti-4Mo-4Cr-X (X = V, Sn, Zr) quaternary alloy for use as a cardiovascular stent. Titanium (Ti) alloys were fabricated using a vacuum arc remelting furnace process. To homogenize the specimens of each composition and remove the micro segregation, all cast specimens were subjected to homogenization at 850℃ for 4 h, which was 100℃ higher than the β-transus temperature of 750℃. The tensile strength and elongation of the aged Ti-4Mo-4Cr-X (X = V, Sn, Zr) alloys were increased as compared to the homogenized alloys. In addition, many α/β interface boundaries formed after aging treatment at 450℃, which acted as inhibitors of strain and caused an increase in tensile strength. The elongation of Ti-4Mo-4Cr-X alloys consisting of α + β phases after aging treatment was improved by greater than 30%. Results of a potentiodynamic polarization test showed that the lowest current density of Ti-4Mo-4Cr-4Sn with 1.05 × 10-8 A/cm2 was obtained. The present Ti-4Mo-4Cr-X alloys showed better corrosion characteristics as compared to the 316L stainless steel and L605 (Co-Cr alloy) cardiovascular stent alloys.