首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
In this work the fatigue and wear behavior of Ti–15Al–33Nb(at.%) and Ti–21Al–29Nb(at.%) was evaluated and compared to that for other titanium-based biomedical implant alloys, in particular Ti–6Al–4V(wt.%). Fatigue stress versus life curves were obtained for tests performed at room temperature in air at a stress ratio of R = 0.1 for maximum stresses between 75%–90% of the ultimate tensile strength. The results indicated that the fatigue strength and lives of the as-processed alloys are comparable to that for Ti–6Al–4V(wt.%). Heat treatment significantly increased the orthorhombic-phase volume fractions in the alloys and resulted in reduced fatigue strength. The wear resistance for the alloys was significantly greater than that for Ti–6Al–4V(wt.%). Based on the current results, it is proposed that titanium–aluminum–niobium alloys will be of considerable future interest for biomedical applications.  相似文献   

2.
In this work the fatigue and tensile behavior of Ti–15Al–33Nb (at.%) and Ti–21Al–29Nb (at.%) was evaluated and compared to that for other titanium-based biomedical implant alloys, in particular Ti–6Al–4V (wt.%). The mechanical properties of interest were fatigue strength, tensile strength, elastic modulus, and elongation-to-failure. Fatigue stress versus life curves were obtained for tests performed at room temperature in air as well as in Ringer's solution at R = 0.1 for maximum stresses between 35% and 90% of the ultimate tensile strength. The results indicated that the fatigue strength and lives and elastic modulus of these alloys is comparable to that for Ti–6Al–4V (wt.%). Considering the data scatter and deformation behavior, the Ringer's solution did not significantly affect the fatigue behavior. Heat treatment reduced the tensile strength and this corresponded to a reduction in the fatigue strength. The tensile strength of the as-processed Ti-Al-Nb alloys was slightly lower than that for Ti–6Al–4V (wt.%), and the Ti–15Al–33Nb (at.%) exhibited lower strengths and higher elongations than Ti–21Al–29Nb. Based on the current results, it is proposed that titanium–aluminum–niobium alloys will be of considerable future interest for biomedical applications.  相似文献   

3.
The corrosion behavior of biocompatible β titanium alloys Ti–13Mo–7Zr–3Fe (TMZF) and Ti–35Nb–7Zr–5Ta (TiOsteum) was investigated in 0.9% NaCl and 5 M HCl solutions. Extra-low-interstitial Ti–6Al–4V, which is also a candidate material for biomedical applications, was studied for comparison. The as-received TiOsteum and TMZF alloys exhibited single-phase β and α + β microstructures, respectively, so the latter was also investigated in the solutionized and quenched condition. In 0.9% NaCl solution, all three alloys exhibited spontaneous passivity and very low corrosion rates. Ti–6Al–4V and the as-received TMZF exhibited active-passive transitions in 5 M HCl whereas TiOsteum and TMZF in the metastable β condition showed spontaneous passivity. Potentiodynamic polarization tests, weight loss and immersion tests revealed that TiOsteum exhibited the best corrosion resistance in 5 M HCl. Analysis of surfaces of the corroded specimens indicated that the α/β phase boundaries were preferential sites for corrosion in Ti–6Al–4V while the β phase was preferentially attacked in the two-phase TMZF. The performance of the alloys in corrosive environment was discussed in terms of the volume fraction of the constituent phases and partitioning of alloying elements between these phases.  相似文献   

4.
Porcelain fused to metal crown (PFM) is widely used in dental restoration for its esthetics. Due to its excellent corrosion resistance, biocompatibility and mechanical properties, commercially pure titanium (c.p. Ti) and Ti–6Al–4V alloy have dramatically improved dental implants and prosthesis, despite the insufficient bond strength of titanium to porcelain. This study investigated the bond strength of new Ti–5Cr–xMo (x = 1–11 wt.%) alloys and low-fusing dental porcelain (Duceratin Plus, DeguDent Gmbh, Germany), and c.p. Ti and Ti–6Al–4V alloy were compared. The results show that Ti–5Cr–9Mo alloy has the highest bond strength (37.67 MPa), a result that is higher than that of c.p. Ti (30.72 MPa) and Ti–6Al–4V (30.01 MPa).  相似文献   

5.
In this investigation, titanium nitride (TiN) reinforcements are synthesized in situ on the surface of Ti–6Al–4V substrates with gas tungsten arc welding (GTAW) process by different methods to add nitrogen, nitrogen gas or TiN powder, to titanium alloys. The results showed that if nitrogen gas was added to titanium alloys, the TiN phase would be formed. But if TiN powder was added to titanium alloys, TiN + TiNx dual phases would be presented. The results of the dry sliding wear test revealed that the wear performance of the Ti–6Al–4V alloy specimen coated with TiN or TiN + TiNx clad layers were much better than that of the pure Ti–6Al–4V alloy specimen. Furthermore, the evolution of the microstructure during cooling was elucidated and the relationship among the wear behavior of the clad layer, microstructures, and microhardness was determined.  相似文献   

6.
β-type titanium alloys consisting of non-toxic elements, Ti–8Fe–8Ta, Ti–8Fe–8Ta–4Zr, and Ti–10Fe–10Ta–4Zr, were newly designed and developed for biomedical applications. Changes in the mechanical properties of the designed alloys with various heat treatments were discussed on the basis of the resultant microstructures. In addition, the corrosion resistance of the designed alloys was evaluated by polarization testing in Hank's solution. Conventional biomedical titanium (cp-Ti) and the titanium alloy Ti–6Al–4V ELI were also polarized for comparison.The structural phase of the designed alloys, after cold rolling and solution treatment, was only the β phase. Ultimate tensile strength and elongation to fracture of Ti–8Fe–8Ta, Ti–8Fe–8Ta–4Zr, and Ti–10Fe–10Ta–4Zr after solution treatment were 1066 MPa and 10%, 1051 MPa and 10%, and 1092 MPa and 6%, respectively. Ti–8Fe–8Ta and Ti–8Fe–8Ta–4Zr have higher strength than those of conventional biomedical titanium alloys such as Ti–6Al–4V ELI, Ti–6Al–7Nb, and Ti–13Nb–13Zr. In particular, the elongations at failure of Ti–8Fe–8Ta and Ti–8Fe–8Ta–4Zr were equal to those of Ti–6Al–4V ELI and Ti–6Al–7Nb. The designed alloys and conventional biomedical titanium alloys were spontaneously passivated in Hank's solution. The current density of cp-Ti and Ti–6Al–4V ELI was increased at a potential above 2.5 V. On the other hand, the current density of the designed alloys abruptly increased at a potential above 3.5 V. The designed alloys have the advantage over cp-Ti and Ti–6Al–4V ELI in their high resistance to pitting corrosion in biological environments.Therefore, new β-type titanium alloys designed in this study, Ti–8Fe–8Ta and Ti–8Fe–8Ta–4Zr, are expected to have good properties as biomaterials.  相似文献   

7.
In this work, the tribocorrosion behavior of Ti–12.5Mo, Ti–13Nb–13Zr and Ti–29Nb–13Ta–4.6Zr β titanium alloys which are candidate biomaterials for joint prostheses is studied against ultra high molecular weight polyethylene in Hank's balanced salt solution. Ti–6Al–4Fe α + β titanium alloy is also tested for comparison. Experiments were carried out at open circuit potential and at a passive applied potential using a pin-on-flat reciprocating sliding tribo-electrochemical apparatus. The potential, anodic current and friction coefficient were measured in situ as a function of time. The β alloys exhibited a tendency to repassivate during sliding at passive and open circuit potential. The predominant wear mechanism of the metal-polyethylene pairs was 3 body wear, exhibited by the transfer of polyethylene to all titanium alloys. Polyethylene showed a comparatively low wear against β titanium alloys. The effect of the addition of synovial fluid constituents, namely bovine serum albumin, hyaluronic acid and dipalmitoyphosphatidylcholine on the tribocorrosion of Ti–29Nb–13Ta–4.6Zr alloy was also studied. The presence of additives affected the friction coefficient, induced an increase of the wear volume, and a modification of the dominant wear mechanism which was identified as abrasion without transfer of polyethylene.  相似文献   

8.
Nanostructured Ti–31.0Fe–9.0Sn and sub-micrometer structured Ti–39.3Nb–13.3Zr–10.7Ta (wt.%) β-type alloys, exhibiting different microstructures and dissimilar mechanical properties, have been prepared by copper mold casting. The microstructure, mechanical behavior and corrosion resistance, in simulated body fluid, of both alloys have been investigated and compared to those of commercial Ti–6Al–4V. Nanoindentation experiments reveal that the Ti–31.0Fe–9.0Sn rods exhibit very large hardness (H  9 GPa) and high Young's modulus. Conversely, the Ti–39.3Nb–13.3Zr–10.7Ta alloy is mechanically softer but it is interesting for biomedical application because of its rather low Young's modulus (E  71 GPa). Concerning the corrosion performance, Ti–35Nb–7Zr–5Ta shows a corrosion behavior comparable to Ti–Al6–V4, with no potential breakdown up to 0.4 V vs. Ag|AgCl. On the contrary, the Ti–31.0Fe–9.0Sn alloy exhibits a more anodic corrosion potential, but the value is still less negative than for pure elemental Fe and Ti. From all these properties and because of the absence of toxic elements in the compositions, the Ti–39.3Nb–13.3Zr–10.7Ta and Ti–31.0Fe–9.0Sn alloys are attractive for use as metallic biomaterials.  相似文献   

9.
Titanium alloys with lower elastic modulus and free from toxic elements such as Al and V have been studied for biomedical matters. Ti–Nb–Sn alloys showed up as presenting great potential for the aforementioned purpose. The current study got Ti–35Nb-XSn alloys (x = 2.5; 5.0; 7.5) by applying the following techniques: arc melting, homogenizing and cooling in furnace, homogenizing and water quenched, hot rolling and water quenched. According to each step of the study, the microstructures were featured by means of optical microscopy, by applying a scanning electron microscopy (SEM) analysis as well as X-ray diffraction. The mechanical properties were gotten by means of: Vickers microhardness, tensile and ultrasonic tests. Their ratio between tensile strength and elastic modulus as well as the ductility were compared to other biomedical alloys already available in the literature. The mechanical behavior of the Ti–Nb alloys directly depends on the Sn rates that constitutes the phases as well as on the thermomechanical background to which the alloy was submitted to. The hot rolled Ti–35Nb–2.5Sn alloy showed high ratio between strength and elastic modulus as well as high ductility, just as high as those of some cold rolled Ti alloys.  相似文献   

10.
This study was undertaken to investigate the influence of Al–5Ti–1B master alloy and modified strain-induced melt activation process on the structural characteristics, mechanical properties and dry sliding wear behavior of Al–12Zn–3Mg–2.5Cu aluminum alloy. The optimum amount of Ti containing master alloy for proper grain refining was selected as 2 wt.%. The alloy was produced by modified strain-induced melt activation (SIMA) process. Reheating condition to obtain a fine globular microstructure was optimized. The optimum temperature and time in strain-induced melt activation process are 575 °C and 20 min, respectively. T6 heat treatment was applied for all specimens before tensile testing. Significant improvements in mechanical properties were obtained with the addition of grain refiner combined with T6 heat treatment. After the T6 heat treatment, the average tensile strength increased from 283 MPa to 587 MPa and 252 MPa to 564 MPa for samples refined with 2 wt.% Al–5Ti–1B before and after strain-induced melt activation process, respectively. Dry sliding wear performance of the alloy was examined in normal atmospheric conditions. The experimental results showed that the T6 heat treatment considerably improved the resistance of Al–12Zn–3Mg–2.5Cu aluminum alloy to the dry sliding wear.The results showed that ultimate strength and dry sliding wear performance of globular microstructure specimens was a lower value than that of Ti-refined specimens without strain-induced melt activation process.  相似文献   

11.
Dissimilar welding of the Ti–6Al–4V (Ti-6-4) to Ti–6A1–6V–2Sn (Ti-6-6-2) alloys was performed by CO2 laser in this work. The effect of post-weld heat treatment (PWHT) on the notched tensile strength (NTS) of the dissimilar weld was evaluated. Moreover, the results were also compared with the homogeneous laser welds with the same PWHT. Similar to the Ti-6-4 welds, the NTS of the FZ for dissimilar welds was less sensitive to PWHT conditions; the NTS of the FZ for distinct dissimilar welds fell within the range of 1060–1180 MPa. The results indicated a minor rise in the Mo equivalent of the titanium alloy promoted the formation of fine α + β microstructures in the form of basket weave in the welds, which resulted in high hardness accompanied with low NTS of the welds.  相似文献   

12.
In this study, Ti–Al–Nb, Ti–Ni–Nb and Ni–Cr–Nb system alloys were designed and incorporated in order to construct a gradient structure at the surface of the joined Ti3Al base material. And the Ti3Al-based alloy and Ni-based superalloy were successfully joined together using gas tungsten arc (GTA) welding technology. The microstructure evolution, mechanical properties and fractured behaviors of the joints were investigated. The gradient structure remarkably decreased the formation tendency of brittle phases within the joints compared with a single filler alloy and thus improved the joint strength effectively. The average room-temperature tensile strength of the Ti3Al/In718 dissimilar joint reached 353 MPa, and the strength value at 873 K was 245 MPa. At the Ti–Ni–Nb/Ni–Cr–Nb interface, some Ni3(Nb, Ti) + (Nb, Ti)Cr2 and TiNi3 phases were detected in the Ti–Ni–Nb matrix. It was believed that their presence decreased the room-temperature strength of the Ti–Ni–Nb alloy but improved its high-temperature strength.  相似文献   

13.
As-cast Ti–5Nb and a series of Ti–5Nb–xCr with Cr content ranging from 1 to 13 mass% prepared by using a commercial arc-melting vacuum-pressure casting system were investigated. Commercially pure titanium (c.p. Ti) was used as a control. X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys obviously had different structures and mechanical properties with the addition of various amounts of Cr. When 1 mass% Cr was added, the structure was comprised mainly of the α′ phase, which was also found in Ti–5Nb. With the addition of 3 mass% Cr, α′ and α′′ phases were appeared. When the Cr content was increased to 5 mass% or greater, the β phase was completely retained. Moreover, the ω phase was detected in the Ti–5Nb–5Cr and Ti–5Nb–7Cr alloys. The largest quantity of ω phase and the highest bending modulus were found in the Ti–5Nb–5Cr alloy, while the Ti–5Nb–9Cr alloy had the lowest bending modulus. Moreover, the high strength/modulus ratios of the Ti–5Nb–3Cr (22.5) and Ti–5Nb–9Cr (21.3) alloys demonstrate its advantage for use as implant materials. Also, these two alloys exhibited the better elastic recovery angles of 28.3° in Ti–5Nb–3Cr and 22.2° in Ti–5Nb–9Cr. In the current search for better implant materials, α′ + α′′ phase Ti–5Nb–3Cr and β phase Ti–5Nb–9Cr alloys with low modulus, ductile property, excellent elastic recovery capability and reasonably high-strength seem to be the most feasible alloy for orthopedic and dental applications if some other necessary properties are obtained.  相似文献   

14.
The inherently poor wear resistance of titanium alloys limits their application as femoral heads in femoral (hip) implants. Reinforcing the soft matrix of titanium alloys (including new generation β-Ti alloys) with hard ceramic precipitates such as borides offers the possibility of substantially enhancing the wear resistance of these composites. The present study discusses the microstructure and wear resistance of laser-deposited boride reinforced composites based on Ti–Nb–Zr–Ta alloys. These composites have been deposited using the LENS™ process from a blend of elemental Ti, Nb, Zr, Ta, and boron powders and consist of complex borides dispersed in a matrix of β-Ti. The wear resistance of these composites has been compared with that of Ti–6Al–4V ELI, the current material of choice for orthopedic femoral implants, against two types of counterfaces, hard Si3N4 and softer SS440C stainless steel. Results suggest a substantial improvement in the wear resistance of the boride reinforced Ti–Nb–Zr–Ta alloys as compared with Ti–6Al–4V ELI against the softer counterface of SS440. The presence of an oxide layer on the surface of these alloys and composites also appears to have a substantial effect in terms of enhanced wear resistance.  相似文献   

15.
Transient Liquid Phase (TLP) bonding of two dissimilar alloys Al7075 and Ti–6Al–4V has been done at 500 °C under 5 × 10−4 torr. Cu was electrodeposited on Al7075 and Ti–6Al–4V surfaces, 50 μm thick Sn–4Ag–3.5Bi film was used as interlayer and bonding process was carried out at several bonding times. The microstructure of the diffusion bonded joints was evaluated by Light Optical Microscopy (LOM), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The eutectic and intermetallic compounds formation along Al7075 grain boundaries and Ti/Al interface such as θ(Al2Cu), TiAl and Ti3Al were responsible for joint formation at the aluminum and titanium interfaces. Microhardness and shear strength tests were used to investigate the mechanical properties of the bonds. Hardness of the joints increased with increasing bonding time which can be attributed to the intermetallics formation at the interface. The study showed that the highest bond strength was 36 MPa which was obtained for the samples joined for 60 min.  相似文献   

16.
The physical, chemical and biological properties of the bioglass reinforced yttria-stabilized composite layer on Ti6Al4V titanium substrates were investigated. The Ti6Al4V substrate was deposited with yttria stabilized zirconia — YSZ as the base layer of thickness ≈ 4–5 μm, to inhibit metal ion leach out from the substrate and bioglass zirconia reinforced composite as the second layer of thickness ≈ 15 μm, which would react with surrounding bone tissue to enhance bone formation and implant fixation. The deposition of these two layers on the substrate was carried out using the most viable electrophoretic deposition (EPD) technique. Biocompatible yttria-stabilized zirconia (YSZ) in the form of nano-particles and sol gel derived bioglass in the form of micro-particles were chosen as precursors for coating. The coatings were vacuum sintered at 900 °C for 3 h. The biocompatibility and corrosion resistance property were studied in osteoblast cell culture and in simulated body fluid (SBF) respectively. Analysis showed that the zirconia reinforced bioglass bilayer system promoted significant bioactivity, and it exhibited a better corrosion resistance property and elevated mechanical strength under load bearing conditions in comparison with the monolayer YSZ coating on Ti6Al4V implant surface.  相似文献   

17.
Corrosion behavior of a multifunctional biomedical titanium alloy Ti–24Nb–4Zr–8Sn (wt.%) in 0.9% NaCl, Hank's solution and artificial saliva at 37 °C was investigated using open circuit potential, impedance spectroscopy and potentiodynamic polarization techniques, and some results were compared with pure titanium and Ti–6Al–4V alloy. The results showed that the alloy exhibited good corrosion resistance due to the formation of a protective passive film consisting mainly of TiO2 and Nb2O5, and a little of ZrO2 and SnO2. Ca ions were detected in the passive film as the alloy immersed in Hank′s and artificial saliva solutions and they have negative effect on corrosion resistance. The EIS results indicated that either a duplex film with an inner barrier layer and an outer porous layer or a single passive layer was formed on the surface, and they all transformed into stable bilayer structure as the immersion time increased up to 24 h. The polarization curves demonstrated that the alloy had a wider passive region than pure titanium and Ti–6Al–4V alloy and its corrosion current density (less than 0.1 μA/cm2) is comparable to that of pure titanium.  相似文献   

18.
Among metallic materials used as bone substitutes, β titanium alloys gain an increasing importance because of their low modulus, high corrosion resistance and good biocompatibility. In this work, an investigation of the in vitro cytocompatibility of a recently new developed β-type Ti–25Ta–25Nb alloy was carried out by evaluating the behavior of human osteoblasts. The metallic Ti–6Al–4V biomaterial, which is one of representative α + β type titanium alloys for biomedical applications, and Tissue Culture Polystyrene (TCPS), were also investigated as reference Ti-based material and control substrate, respectively. Both metallic surfaces were analyzed by X-ray diffraction, atomic force microscopy and X-ray photoelectron spectroscopy. The cellular response was quantified by assessments of viability, cell attachment and spreading, cell morphology, production and extracellular organization of fibronectin and cell proliferation. Polished surfaces from both materials having an equiaxed grain microstructure and nanometre scale surface roughness elicited an essentially identical osteoblast response in terms of all analyzed cellular parameters. Thus, on both surfaces the cells displayed high survival rates, good cell adhesion and spreading, a dense and randomly dispersed fibronectin matrix and increasing cell proliferation rates over the incubation time. Furhermore, the enhanced biological performance of Ti–25Ta–25Nb was highly supported by the results obtained in comparison with TCPS. These findings, together with previously shown superelastic behavior, low Young's modulus and high corrosion resistance, recommend Ti–25Ta–25Nb as good candidate for applications in bone implantology.  相似文献   

19.
Tensile and plain fatigue properties of β type titanium alloy, Ti–29Nb–13Ta–4.6Zr, which underwent various thermo-mechanical treatments, were investigated in order to judge its potential for biomedical applications.Microstructures of Ti–29Nb–13Ta–4.6Zr (TNTZ) aged directly at 723 K for 259.2 ks after cold rolling and TNTZ aged at 723 K for 259.2 ks after solution treatment are composed of precipitated α phase in β phase. While, microstructures of TNTZ aged directly at 598 K and 673 K for 259.2 ks after cold rolling and aged at 598 K and 673 K for 259.2 ks after solution treatment are composed of precipitated ω phase, and precipitated α and ω phases in β phase, respectively. Tensile strength of aged TNTZ after solution treatment and aged TNTZ after cold rolling decreases with increasing aging temperature although the elongation shows the reverse trend. TNTZ composed of ω phase or ω and α phases in β phase shows the tensile strength of around 1000 MPa or more. Young's moduli of aged TNTZ after solution treatment and aged TNTZ after cold rolling decrease with increasing aging temperature. TNTZ conducted with solution treatment has the lowest Young's modulus of around 60 GPa. Fatigue strengths of aged TNTZ after solution treatment and aged TNTZ after cold rolling increase with increasing aging temperature. In particular, TNTZ aged directly at 723 K after cold rolling shows the greatest fatigue strength in both low cycle fatigue life and high cycle fatigue life regions, and the fatigue limit, which is around 770 MPa, is nearly equal to that of hot-rolled Ti–6Al–4V ELI conducted with aging, which is one of representative α + β type titanium alloys for biomedical applications.  相似文献   

20.
For the first stage, a metastable β titanium alloy, Ti–3.5Al–5Mo–4V–2Cr–2Sn–2Zr–1Fe reinforced with trace amounts of TiB whiskers and TiC particles was fabricated by vacuum arc melting process and hot forging followed by heat treatment at 780 °C/740 °C, then by aging at 500 °C, 550 °C, 570 °C and 600 °C. For the second stage, the unreinforced titanium alloy was also fabricated by the same process. The microstructural characteristics were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Traces of TiB whiskers and TiC particles (2.2 vol.%) with a volume ratio of 2:3 synthesized in situ exerted a hybrid reinforcing effect on the β titanium alloy. The reinforcements were uniformly distributed in the matrix and the elastic modulus was improved about 25 GPa. Ultimate tensile strength and yield strength achieves about 1625 MPa and 1500MPa respectively, with ductility at 7% when the aging temperature is 500 °C. The ductility of (TiB + TiC)/(Ti–3.5Al–5Mo–4 V–2Cr–2Sn–2Zr–1Fe) matrix composite could be enhanced by increasing the aging temperatures. After 780 °C followed by aging at 570 °C, excellent strength and plasticity properties were obtained (ultimate tensile strength of matrix alloy is 1350 MPa with elongation of 18% and ultimate tensile strength of composite is 1500 MPa with elongation of 13%).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号