Osseointegration behavior of novel Ti–Nb–Zr–Ta–Si alloy for dental implants: an in vivo study

This study aimed to evaluate the effects of Ti–Nb–Zr–Ta–Si alloy implants on mineral apposition rate and new BIC contact in rabbits. Twelve Ti–Nb–Zr–Ta–Si alloy implants were fabricated and placed into the right femur sites in six rabbits, and commercially pure titanium implants were used as controls in the left femur. Tetracycline and alizarin red were administered 3 weeks and 1 week before euthanization, respectively. At 4 weeks and 8 weeks after implantation, animals were euthanized, respectively. Surface characterization and implant-bone contact surface analysis were performed by using a scanning electron microscope and an energy dispersive X-ray detector. Mineral apposition rate was evaluated using a confocal laser scanning microscope. Toluidine blue staining was performed on undecalcified sections for histology and histomorphology evaluation. Scanning electron microscope and histomorphology observation revealed a direct contact between implants and bone of all groups. After a healing period of 4 weeks, Ti–Nb–Zr–Ta–Si alloy implants showed significantly higher mineral apposition rate compared to commercially pure titanium implants (P?<?0.05), whereas there was no significant difference between Ti–Nb–Zr–Ta–Si alloy implants and commercially pure titanium implants (P?>?0.05) at 8 weeks. No significant difference of bone-to-implant contact was observed between Ti–Nb–Zr–Ta–Si alloy implants and commercially pure titanium implants implants after a healing period of 4 weeks and 8 weeks. This study showed that Ti–Nb–Zr–Ta–Si alloy implants could establish a close direct contact comparedto commercially pure titanium implants implants, improved mineral matrix apposition rate, and may someday be an alternative as a material for dental implants.     

Tribocorrosion behavior of β titanium alloys in physiological solutions containing synovial components

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.     

Mechanical properties and cyto-toxicity of new beta type titanium alloy with low melting points for dental applications

Beta stabilized new alloys such as Ti–29Nb–13Zr–2Cr, Ti–29Nb–15Zr–1.5Fe, Ti–29Nb–10Zr–0.5Si, Ti–29Nb–10Zr–0.5Cr–0.5Fe and Ti–29Nb–18Zr–2Cr–0.5Si have been developed for dental applications. These alloys were designed based on master alloy Ti–29Nb–13Ta–4.6Zr (TNTZ) for biomedical applications. In this research, high melting temperature element Ta was replaced with beta stabilizing elements such as Cr, Fe and Si to lower the melting temperature of the alloy.Their melting points, mechanical properties, surface reaction layers and cyto-toxicity were investigated in this study.Melting points of designed alloys fall by about 50 K to 370 K as compared with that of TNTZ, and Ti–29Nb–13Zr–2Cr has the lowest melting point of around 2050 K. Vickers hardness of the surface of each designed alloy cast into modified magnesia based investment material is in the range of 400 Hv to 500 Hv, which is lower than that of TNTZ (around 560 Hv).Balances of strength and ductility of cast Ti–29Nb–13Zr–2Cr, Ti–29Nb–15Zr–1.5Fe and Ti–29Nb–10Zr–0.5Cr–0.5Fe are nearly equal to that of cast TNTZ.Cell viability of each cast designed alloy is excellent.     

Wear resistance of laser-deposited boride reinforced Ti-Nb–Zr–Ta alloy composites for orthopedic implants

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.     

Wear properties of Ti–13Zr–13Nb (wt.%) near β titanium alloy containing 0.5 wt.% boron in dry condition,Hank's solution and bovine serum

The effect of heat treatment on the microstructure, hardness and sliding wear behaviour of Ti–13Zr–13Nb (wt.%) containing 0.5 wt.% B (TZNB) has been studied and compared with that of Ti–13Zr–13Nb (wt.%) (TZN) alloy. The wear properties were tested in dry condition and in simulated body fluid (Hank's solution and bovine serum) to understand the effect of different medium on wear behaviour of the TZNB alloy. Depending on the heat treatment condition the microstructure of the alloy consisted of α/martensite and TiB in β matrix. In general, the hardness of all the heat treated samples varied in a narrow range and in most of the cases addition of boron to the TZN alloy decreased the hardness. Almost all cases, no significant variation of the wear rate in dry condition with heat treatment was observed. Compared with the wear rate in dry condition, the wear rate in Hank's solution of the all the TZNB samples increased substantially. Moreover, the wear was found to be most severe in bovine serum. Addition of boron to TZN alloy did not result in any improvement in the wear resistance in all the media studied.     

Fibroblast Adhesion and Proliferation on a New β Type Ti-39Nb-13Ta-4.6Zr Alloy for Biomedical Application

Cell attachment and spreading on Ti-based alloy surfaces is a major parameter in implant technology. Ti-39Nb-13Ta-4.6Zr alloy is a new β type Ti alloy developed for biomedical application. This alloy has low modulus and high strength, which indicates that it can be used for medical purposes such as surgical implants. To evaluate the biocompatibility and effects of the surface morphology of Ti-39Nb-13Ta-4.6Zr on the cellular behaviour, the adhesion and proliferation of rat gingival fibroblasts were studied with substrates having different surface roughness and the results were also compared with commercial pure titanium and Ti-6Al-4V. The results indicate that fibroblast shows similar adhesion and proliferation on the smooth surfaces of commercial pure titanium （Cp Ti）, Ti-39Nb-13Ta-4.6Zr, and Ti-6Al-4V, suggesting that Ti-39Nb-13Ta-4.6Zr has similar biocompatibility to Cp Ti and Ti-6Al-4V. The fibroblast adhesion and spreading was lower on rough surfaces of Cp Ti, Ti-39Nb-13Ta-4.6Zr and Ti-6Al-4V than on smooth ones. Surface roughness appeared to be a dominant factor that determines the fibroblast adhesion and proliferation.     

Fibroblast Adhesion and Proliferation on a New β Type Ti-39Nb-13Ta-4.6Zr Alloy for Biomedical Application

Cell attachment and spreading on Ti-based alloy surfaces is a major parameter in implant technology. Ti39Nb-13Ta-4.6Zr alloy is a new β type Ti alloy developed for biomedical application. This alloy has low modulus and high strength, which indicates that it can be used for medical purposes such as surgical implants.To evaluate the biocompatibility and effects of the surface morphology of Ti-39Nb-13Ta-4.6Zr on the cellular behaviour, the adhesion and proliferation of rat gingival fibroblasts were studied with substrates having different surface roughness and the results were also compared with commercial pure titanium and Ti-6Al-4V. The results indicate that fibroblast shows similar adhesion and proliferation on the smooth surfaces of commercial pure titanium (Cp Ti), Ti-39Nb-13Ta-4.6Zr, and Ti-6Al-4V, suggesting that Ti-39Nb-13Ta-4.6Zr has similar biocompatibility to Cp Ti and Ti-6Al-4V. The fibroblast adhesion and spreading was lower on rough surfaces of Cp Ti, Ti-39Nb-13Ta-4.6Zr and Ti-6Al-4V than on smooth ones. Surface roughness appeared to be a dominant factor that determines the fibroblast adhesion and proliferation.     

Mechanical properties and microstructures of new Ti–Fe–Ta and Ti–Fe–Ta–Zr system alloys

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.     

Calcium phosphate coating of Ti–Nb–Zr–Sn titanium alloy

This study focuses on rapid formation of calcium phosphate coating on a β type Ti–Nb–Zr–Sn biomedical titanium alloy by alkali treatment. The results show that a bioconductive surface layer forms on specimens immersed in 1–5 M KOH solution but only treatment in 1 M KOH avoids formation of crevices, producing a potassium titanate layer with porous network structure. Heat treatment at 600 °C after the alkali treatment promotes titanate growth. Following the above treatments, a continuous apatite layer forms within 4 h of soaking in a calcium phosphate solution with high ionic concentration. Such rapid apatite formation is due to high concentration of calcium ions in the solution used in this study and the buffering function of NaHCO₃. Results of dissolution experiment show that Ca and P ions release gradually from the coating during soaking in a 0.9% NaCl solution, which may be helpful to the formation of natural bone if implanted in human body. Cell culture experiment shows that the apatite layer favours adhesion and proliferation of rat osteoblast as compared with coating-free Ti–Nb–Zr–Sn alloy and commercially pure titanium (CP Ti).     

Metastable Beta Titanium Alloys for Orthopedic Applications

This article provides an overview of metastable β titanium alloys either being utilized or being considered for use in orthopedic applications. The effects of thermomechanical processing on the mechanical properties (e.g., elastic modulus, tensile, wear and high cycle fatigue performance) of Ti‐15Mo‐0.2O, Ti‐12Mo‐6Zr‐2Fe (TMZF), Ti‐29Nb‐13Ta‐4.6Zr and Ti‐35Nb‐7Zr‐5Ta are reviewed. The osteointegration behavior of Ti‐29Nb‐13Ta‐4.6Zr and Ti‐35Nb‐7Zr‐5Ta‐O alloys is also presented.     

Surface hardening of biomedical Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V ELI by gas nitriding

The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to gas nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After gas nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti₂N) are formed and the phase is precipitated by gas nitriding. Furthermore, the oxygen impurity in the gas nitriding atmosphere reacts with the titanium nitrides; thus, TiO₂ is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by gas nitriding.     

不同温度下等离子渗氮后TC4钛合金的摩擦磨损性能EI北大核心CSCD

采用等离子渗氮技术提升TC4钛合金的耐磨性并探究最优渗氮温度。利用LDM 1-100型等离子渗氮设备,在650,700,750,800,850℃和900℃温度下对TC4钛合金进行渗氮处理,保温时间均为10 h。利用光学显微镜、扫描电子显微镜、白光三维形貌仪、X射线衍射仪和显微硬度计分别对不同温度渗氮试样的微观组织结构、表面形貌、表面粗糙度、相结构和硬度进行表征。利用CETR UMT-3型多功能摩擦磨损试验机测试等离子渗氮后TC4钛合金的摩擦学性能。结果表明:TC4钛合金表面显微硬度和粗糙度随温度升高而增大,在900℃渗氮后TC4钛合金表面显微硬度达到了1318HV 0.05,约为基体(360HV 0.05)的4倍。硬度的升高是由于渗氮后试样表面形成了硬质氮化物相(TiN和Ti2N相),且随着渗氮温度升高氮化物的含量增加。相较于低温渗氮(低于750℃)的试样,850℃和900℃渗氮试样的承载能力显著提升。与原始TC4试样相比,渗氮处理后试样的磨损体积显著降低。当渗氮温度为850℃时,试样磨损体积为未处理试样磨损体积的1.2%(1 N),3.0%(3 N)和62.2%(5 N),试样的耐磨性提升更为显著。     

Microstructure and mechanical properties of copper–titanium–nitrogen multiphase layers produced by a duplex treatment on C17200 copper–beryllium alloy

In this study, a copper–titanium–nitrogen multiphase coating was fabricated on the surface of C17200 copper–beryllium alloy by deposition and plasma nitriding in order to improve the surface mechanical properties. The phase composition, microstructure and microhardness profiles of the as-obtained multiphase coating were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and Vickers microhardness measurements, respectively. Pin-on-disk tribometer and SEM equipped with energy dispersive spectrometer (EDS) were applied to measure tribological properties and analyze wear mechanisms involved. The XRD results show that the phase composition changes with nitriding temperature. The Ti₂N layer is replaced by a Cu–Ti intermetallic layer when the nitriding temperature is higher than 700 °C. The Cu/Ti ratio in the multiphase coatings remains at a constant value of 2:1 due to the incorporation of nitrogen atoms. The surface hardness achieves a maximum value of 983 HV at 650 °C, and decreases as the nitriding temperature increases. The increased hardness corresponds to the improved wear resistance and decreased frictional coefficient and the surface hardness is proportional to the wear rates. The wear mechanism depends on the phase composition of the multiphase coatings. With the nitriding temperature increasing, the oxidative wear mechanism changes to adhesive and abrasive mode.     

High‐cycle fatigue properties of beta Ti alloy 55Ti–30Nb–10Ta–5Zr,gum metal

This paper describes the fatigue properties of the beta titanium alloy 55Ti–30Nb–10Ta–5Zr, generally referred to as ‘Gum Metal’. Rotating bending fatigue tests have been performed in laboratory air and in a 3% NaCl aqueous solution. The results obtained were compared with those of a conventional beta titanium alloy, Ti–22V–4Al. In tensile tests, 55Ti–30Nb–10Ta–5Zr indicated elasticity and microplasticity in the elastic region. Thus, the elastic modulus slightly decreased with an increasing strain, and the work hardening was minimal during plastic deformation. The mechanical properties of both of the alloys were comparable. The fatigue strength of 55Ti–30Nb–10Ta–5Zr in laboratory air was higher than that of Ti–22V–4Al, which could be attributed to the higher fatigue crack initiation resistance of 55Ti–30Nb–10Ta–5Zr than Ti–22V–4Al, while the resistance to small fatigue crack growth was similar. The fatigue strength of 55Ti–30Nb–10Ta–5Zr in laboratory air and in the 3% NaCl aqueous solution was analogous. In addition, corrosion pits were not observed in the run‐out specimen in the 3% NaCl aqueous solution, indicating a high resistance of 55Ti–30Nb–10Ta–5Zr against corrosion fatigue.     

Production of Ti–13Nb–13Zr Alloy by Powder Metallurgy (P/M) via Sintering Hydrides

The blended elemental method was selected for the manufacture of Ti–13Nb–13Zr alloy by a cold isostatic pressing process and sintering densification under high vacuum. The samples were sintered at the different temperatures from 1250°C to 1450°C with a pressure of 10^?3 ～ 10^?5 Pa. The decomposition of titanium, niobium, and zirconium hydride powders was discussed by thermal gravimetric analyses and differential scanning calorimetry. The phase composition, microstructure and fracture morphology of Sintered Ti–13Nb–13Zr samples were determined by X-ray diffraction and scanning electron microscopy. The results indicate that the hydrogen can be removed effectively. Chemical analysis shows that the Nb, Zr alloying element and hydrogen contents accord with the standard of the ASTM-1713. The final density of sintered Ti–13Nb–13Zr specimens is 4.99 g cm^?3 after sintering at 1450°C for 4 h, representing 99.69% of the theoretical density. The microstructure of sintered Ti–13Nb–13Zr alloys by powder metallurgy is a typical Widmannstätten (α + β).     

Evaluation of the effects of plasma nitriding temperature and time on the characterisation of Ti 6Al 4V alloy

The effects of plasma nitriding (PN) temperature and time on the structural and tribological characterisation of Ti 6Al 4V alloy were investigated. PN processes under gas mixture of N₂/H₂ = 4 were performed at temperatures of 700, 750, 800 and 850 °C for duration of 2, 5 and 10 h. Cross section and surface characterisation were evaluated by means of SEM, AFM, XRD and microhardness test techniques. Dry wear tests were performed using a pin on disc machine. Mass loss and coefficient of friction were measured during the wear tests. Three distinguished structures including of a compound layer (constituted of δ-TiN and ɛ-Ti₂N), an aluminium-rich region and a diffusion zone (interstitial solid solution of nitrogen in titanium) were detected at the surface of plasma nitrided Ti 6Al 4V alloy. These structures increased surface hardness of Ti 6Al 4V alloy significantly and gradually distributed the hardness from the surface to the substrate. The "surface hardness", "surface roughness", "wear resistance" and "coefficient of friction" of the alloy were increased due to plasma nitriding process. Moreover, rising both process temperature and time led to increasing of "layers thicknesses", "surface hardness", "surface roughness", "dynamic load-ability" and "wear resistance" of Ti 6Al 4V alloy.     

Biomimetic Titanium Alloy with Sparsely Distributed Nanotubes Could Enhance Osteoblast Functions

Designing the bone implant surface by mimicking the structure of natural tissue is an intriguing means to achieve better osseointegration. In this study, a biomimetic surface with sparsely distributed 80 nm diameter nanotubes (SNT) with a spacing of about 20–80 nm from each other, contrary to the closely distributed nanotubes on pure titanium, is fabricated by anodization of near β titanium alloy Ti‐5Zr‐3Sn‐5Mo‐15Nb (TLM). The structure is more similar to the cross‐section of collagen fibrils than commonly reported nanotubes on pure titanium. The SNT‐textured Ti‐alloy also shows good wettability and low elastic modulus more compatible with bone tissues. The surface bioactivity is evaluated in vitro by primary osteoblast cultures. Compared with the polished non‐textured TLM, the SNT texture exhibits satisfactory bioactivity with protein adsorption, initial cell adhesion, cell differentiation as revealed by ALP activity and osteogenesis‐related gene expression. Although cell proliferation is slightly suppressed, ECM deposition is enhanced. The enhanced cell functions are probably related to the biomimetic structure, biochemical characteristics, and mechanical properties of SNT‐textured Ti‐alloy as well as the potential fluid exchange effect among the nanotubes. The SNT texture which constitutes a bio‐interface with fluid supply from the implant surface can be tailored to enhance biological properties such as cell immigration and differentiation.     

Corrosion behavior of biomedical Ti–24Nb–4Zr–8Sn alloy in different simulated body solutions

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.     

Production of new titanium alloy for orthopedic implants

The beta titanium alloys is one of the most promising groups of the titanium alloys. This fact is due to the good formability, mechanical properties and potential applications; moreover, these alloys present the highest level of mechanical, fatigue and corrosion resistance. The beta titanium alloys present the lowest elastic modulus, an interesting property for orthopedic implants. A β alloy recently developed for this application is Ti–35Nb–7Zr–5Ta. In this work, the alloy was produced by powder metallurgy, unique available alternative for obtaining parts with porous structure (until 50% of porosity), that is one important characteristic for the osteointegration. The Ti–35Nb–7Zr–5Ta samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering among 900 at 1700 °C, in vacuum. The objective of this work is the analysis of alloy microstructural evolution from the elemental powders dissolution under the increase of the sintering temperature. The alloy was characterized by scanning electron microscopy, X-ray diffraction and Vickers microhardness measurements. Density was measured by Archimedes method. The results show that a β-homogeneous microstructure is obtained in the whole sample with the increase of sintering temperature. With the beginning of the β-stabilizers (Nb and Ta) dissolution, at low sintering temperatures, there is the formation of an intermediary Widmanstätten (α+β) phase.     

Microstructure and Wear Resistance of in situ Formed Duplex Coating Fabricated by Plasma Nitriding Ti Coated 2024 Al Alloy

In this study, plasma nitriding was carried out on pure titanium film coated 2024 Al alloy to improve its surface mechanical property. Ti film with the thickness of 3.0 mm was firstly fabricated by means of magnetron sputtering method. Then, the Ti coated specimen was subjected to plasma atmosphere comprising 40% N2e60% H2 at 430 C for 8 h. The microstructures of the nitrided specimens were characterized by X-ray diffraction and scanning electron microscopy. Microhardness tester and pin-on-disc tribometer were used to test the mechanical properties of the untreated and nitrided specimen. The results showed that the surface of the nitrided specimen was composed of three layers（i.e. the outside nitride Ti N0.3layer, the middle Al3 Ti layer and the inside Al18Ti2Mg3 layer）. The surface hardness and wear resistance of 2024 Al alloy were increased simultaneously by duplex treatment. The untreated specimen exhibited severe adhesive wear while the nitrided one behaved in middle abrasive wear.