scholarly journals Surface engineering of titanium by multi-interstitial diffusion using plasma processing

2020 ◽  
Vol 321 ◽  
pp. 11010
Author(s):  
M. Drouet ◽  
L. Pichon ◽  
J.B. Dubois ◽  
E. Le Bourhis ◽  
T. L. Christiansen
Keyword(s):  
Surface Engineering ◽  
Plasma Nitriding ◽  
Compound Layer ◽  
Case Depth ◽  
Surface Compound ◽  
Specific Strength ◽  
High Specific Strength ◽  
Excellent Corrosion Resistance ◽  
Composition Profiles ◽  
Hardness Depth

Titanium and its alloys possess a range of highly interesting properties such as excellent corrosion resistance, high specific strength and biocompatibility, but suffers from poor wear resistance. The present work addresses plasma assisted surface treatment of CP 2 titanium using various combinations of oxygen and nitrogen, i.e. mixed interstitials. The sequence of controlled plasma nitriding and oxidizing treatments plays a significant role for the evolution of the hardness depth profiles and the development of the surface compound layer and the underlying diffusion/transition zone. Composition profiles of oxygen and nitrogen are obtained by GDOES; Mixed interstitial solubility of nitrogen and oxygen is found in both h.c.p. α titanium and in the compound layer. The combination of interstitials leads to larger case depth, in particular for the diffusion zone (expanded h.c.p. α titanium). Therefore, it highlights the advantages of combined nitriding and oxidizing compared to single nitriding treatments on the mechanical properties.

The Influence of the Microwave Plasma Nitrided Ti6Al4V Substrate Properties to the Duplex Coating Performance

2015 ◽  
Vol 761 ◽  
pp. 68-72 ◽  
Author(s):  
Yusliza Yusuf ◽  
Zulkifli Rosli ◽  
Jariah Mohd Juoi ◽  
Omar Nooririnah ◽  
Umar Al Amani Azlan
Keyword(s):  
Microwave Plasma ◽  
Plasma Nitriding ◽  
Microstructural Analysis ◽  
Surface Hardness ◽  
Weight Ratio ◽  
Medical Application ◽  
Compound Layer ◽  
Case Depth ◽  
Duplex Coating ◽  
Depth Analysis

Titanium alloys, especially TI6Al4V has been used in many industries such as aerospace applications, medical application and automotive applications. This is because it has beneficial properties such as low density, high strength to weight ratio, low modulus elasticity, excellent corrosion resistance and etc. However, titanium and its alloys have limited use in mechanical engineering applications involving sliding wear or abrasion due to poor wear resistance. Therefore, the duplex coating concept was introduced with the intention of the surface modification process as a pre-treatment of the substrate prior to the deposition of hardcoating process. In this study, plasma nitriding of the Ti6Al4V was performed using a microwave plasma technique at 600°C and 700°C for 1 hour, 3 hours and 5 hours, then followed by deposition of chromium nitrate (CrN) on plasma nitrided samples for duplex coating purposes. Microstructural analysis and mirohardness measurement revealed that formation of Ti2N and TiN phase indicating the formation of the compound layer was observed for substrate nitrided at temperature as low as 600°C for 1 hour and a substantial increase on the case depth obtained on plasma nitrided Ti6Al4V was observed with an increase of process temperature and time. The duplex coating obtained in this study has superior surface hardness property and improved load carrying capacity of the coating – substrate system compared to CrN coatings deposited on as received Ti6Al4V which was observed in the penetration depth analysis.

Diffusion of Oxygen in some Binary Ti-Based Alloys Used as Biomaterials

2015 ◽  
Vol 364 ◽  
pp. 165-173
Author(s):  
Carlos Roberto Grandini
Keyword(s):  
Crystalline Lattice ◽  
Specific Strength ◽  
High Specific Strength ◽  
Ti Alloys ◽  
Excellent Corrosion Resistance ◽  
Low Elastic Modulus ◽  
Exponential Factors ◽  
Good Biocompatibility ◽  
Effect Of Oxygen ◽  
Interstitial Elements

Ti and its alloys are widely used as biomaterials. Their main properties are excellent corrosion resistance, relatively low elastic modulus, high specific strength, and good biocompatibility. The development of new Ti alloys with properties favorable for use in the human body is desired. To this end, Ti alloys with Mo, Nb, Zr, and Ta are being developed, because these elements do not cause cytotoxicity. The presence of interstitial elements (such as oxygen and nitrogen) induces strong changes in the elastic properties of the material, which leads to hardening or softening of the alloy. By means of anelastic spectroscopy, we are able to obtain information on the diffusion of these interstitial elements present in the crystalline lattice. In this paper, the effect of oxygen on the anelastic properties of some binary Ti-based alloys was analyzed with anelastic spectroscopy. The diffusion coefficients, pre-exponential factors, and activation energies were calculated for oxygen and nitrogen in these alloys.

scholarly journals Influence of soft interlayers on fretting fatigue and fretting wear resistance of Ti-6Al-4V alloy

2020 ◽  
Vol 321 ◽  
pp. 04017
Author(s):  
Amin Ma ◽  
Daoxin Liu ◽  
Xiaohua Zhang
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Copper Foil ◽  
Fretting Fatigue ◽  
Nickel Foil ◽  
Fretting Wear ◽  
Specific Strength ◽  
High Specific Strength ◽  
Excellent Corrosion Resistance ◽  
Copper Interlayer

Ti-6Al-4V alloy is the main structure material of aerospace components due to its excellent corrosion resistance, high specific strength and other good characteristics. However, this alloy has low hardness, poor wear resistance and higher friction coefficient, so it is very sensitive to fretting wear (FW) and fretting fatigue (FF) damages. In this work, we studied three kinds of soft inter-layers (copper foil, nickel foil and polytetrafluoroethylene (PTFE) lamella) between the Ti-6Al-4V fatigue samples and the Ti-6Al-4V counterparts respectively to enhance the FF and FW resistance of this alloy. The results show that the method is an economical and effective way to increase the FF and FW resistance of Ti-6Al-4V alloy. The order of enhancement in the FF resistance of the titanium alloy was copper foil > PTFE lamella > nickel foil. Additionally, the friction coefficients of PTFE lamella, copper foil, nickel foil and Ti-6Al-4V alloy were about 0.10, 0.60, 0.65 and 1.1, respectively. The lowest friction coefficient of PTFE, compared with copper foil, nickel foil and substrate, was of great benefit to improving the FF property of Ti-6Al-4V alloy. Nevertheless, the FF life of Ti-6Al-4V alloy with the copper interlayer was higher than PTFE, which was about 5 times higher than substrate.

Precipitation in Al-Li-Cu Alloys

1981 ◽  
Vol 39 ◽  
pp. 44-45
Author(s):  
J. E. O'Neal ◽  
K. K. Sankaran
Keyword(s):  
Electron Microscopy ◽  
Age Hardening ◽  
Precipitation Behavior ◽  
Zone Formation ◽  
Specific Strength ◽  
Hardening Behavior ◽  
Cu Alloys ◽  
High Specific Strength ◽  
Transmission Electron ◽  
Structural Applications

Al-Li-Cu alloys combine high specific strength and high specific modulus and are potential candidates for aircraft structural applications. As part of an effort to optimize Al-Li-Cu alloys for specific applications, precipitation in these alloys was studied for a range of compositions, and the mechanical behavior was correlated with the microstructures.Alloys with nominal compositions of Al-4Cu-2Li-0.2Zr, Al-2.5Cu-2.5Li-0.2Zr, and Al-l.5Cu-2.5Li-0.5Mn were argon-atomized into powder at solidification rates ≈ 103°C/s. Powders were consolidated into bar stock by vacuum pressing and extruding at 400°C. Alloy specimens were solution annealed at 530°C and aged at temperatures up to 250°C, and the resultant precipitation was studied by transmission electron microscopy (TEM).The low-temperature (≲100°C) precipitation behavior of the Al-4Cu-2Li-0.2Zr alloy is a combination of the separate precipitation behaviors of Al-Cu and Al-Li alloys. The age-hardening behavior at these temperatures is characteristic of Guinier-Preston (GP) zone formation, with additional strengthening resulting from the coherent precipitation of δ’ (Al3Li, Ll2 structure), the presence of which is revealed by the selected-area diffraction pattern (SADP) shown in Figure la.

Microstructural Evolution in Al-Ti Multilayered Film with Annealing

1999 ◽  
Vol 5 (S2) ◽  
pp. 836-837
Author(s):  
R. Mitra ◽  
W.A. Chiou ◽  
A.Madan ◽  
R. Hoffman ◽  
J.R. Weertman
Keyword(s):  
Magnetron Sputtering ◽  
Ingot Metallurgy ◽  
Multilayered Film ◽  
Multilayered Structures ◽  
Multilayered Films ◽  
Specific Strength ◽  
The Past ◽  
High Specific Strength ◽  
Significant Interest ◽  
Deposited Film

There has been a significant interest in the development of dispersion-hardened aluminum for many years for high specific strength and modulus. Such materials are usually processed by powder or ingot metallurgy routes. In this study, Al3 Ti dispersion hardened Al was obtained by annealing Al-Ti multilayers. Al-Ti multilayered films have been characterized in the past by observing the structure of the layers, as well as tensile properties and hardness. This paper reports the structure of Al-Ti multilayers and the evolution of matrix and dispersoid microstructure on annealing.The Al-Ti multilayered structures were prepared by magnetron sputtering using Al and Ti as targets and either Si (100) or NaCl as substrates. The bi-layer thickness was maintained around 16 nm with Ti constituting 12% of the total. The substrate was alternately moved below the Al and Ti targets for the purpose of deposition. The as-deposited film on the substrate and NaCl salts were annealed at 400°C for periods between 1 and 24 h in a vacuum (10−5 torr) furnace.

Influence of the Flux Ratio N2/Ar on the Formation of Mo-N Modification Layers on Ti6Al4V by Plasma Reactive Sputtering

2009 ◽  
Vol 610-613 ◽  
pp. 1128-1131
Author(s):  
Xiu Yan Li ◽  
Ying Zhang ◽  
Bin Tang ◽  
Zhong Xu
Keyword(s):  
Substrate Surface ◽  
Surface Hardness ◽  
Flux Ratio ◽  
Reactive Sputtering ◽  
Load Bearing Capacity ◽  
Specific Strength ◽  
The Poor ◽  
High Specific Strength ◽  
Composition Structure ◽  
Oriented Parallel

Ti6Al4V alloy is promising biology material with outstanding properties of low density, high specific strength, and exceptional corrosion resistance. However, one of its disadvantages is the poor tribological property. In this paper Mo-N hard surface modification layers were formed on Ti6Al4V at 900°C substrate temperature by plasma reactive sputtering. The flux ratio N2/Ar is an important parameter and its influence on the composition, structure and hardness of the Mo-N layers is studied. The Mo-N layers are duplex layers, composed of diffusing layer and surface coating. The component of Mo and N elements in the diffusing layer changes gradually which can enhance the load-bearing capacity to the coating and ensure the durability of the coating. With the increase of the flux ratio N2/Ar, the content of N element in the Mo-N layers increases. The Mo-N layers were polycrystalline γ- Mo2N with (200) plane oriented parallel to the substrate surface. The surface hardness of the formed layers is in the range HK1330-1430. The hardness of the Mo-N layers increases with the increase of the flux ratio N2/Ar and the reason is that the content of N element in the Mo-N layers increases.

Research Progress of the Surface Oxidation of Titanium and its Alloys

2013 ◽  
Vol 748 ◽  
pp. 188-191
Author(s):  
Hui Jun Yu
Keyword(s):  
Titanium Alloys ◽  
Biomedical Applications ◽  
Influence Factors ◽  
Surface Oxidation ◽  
Research Progress ◽  
Corrosion Resistant ◽  
Specific Strength ◽  
Existing Problems ◽  
High Specific Strength ◽  
Micro Arc Oxidation

Titanium and titanium alloys possess some attractive properties, such as excellent corrosion and erosion resistance, low densities, high specific strength and modulus, enabling them extensively used in aeronautical, marine, chemical and biomedical applications and so on. Nevertheless, Recent years, the corrosion resistance of titanium and titanium alloys is required to elevate in some fields, proper surface modification such as surface oxidation can solve the problems effectively. In this paper, the recent investigations of thermal oxidation and micro-arc oxidation to improve the corrosion resistant of titanium and its alloys are reviewed. The structures, properties and their influence factors of the coatings are analysed systematically. And the existing problems and the future prospect of the further researches is mentioned.

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