Nanostructured Ti2448 Biomedical Titanium Alloy

2009 ◽  
Vol 633-634 ◽  
pp. 535-547 ◽  
Author(s):  
Yu Lin Hao ◽  
Shi Jian Li ◽  
M.L. Sui ◽  
Rui Yang

It is generally accepted that grain refinement by the mechanisms of dislocation interaction, deformation twinning and/or stress-induced martensitic transformation is of relatively low efficiency. Rapid production of nanostructured metallic materials by conventional processing technologies remains a challenge. A new mechanism of fast grain refinement, through highly localized plastic deformation, was recently found in a -type biomedical titanium alloy (Ti2448). This mechanism leads to rapid grain refinement to tens nanometers and even amorphous transition during conventional cold processing. Since such grain refinement induces little strengthening, this process was previously termed soft nanostructuring. Here we review the research into this new way of nanostructuring and discuss the mechanism of grain refinement as well as dispersion strengthening of Ti2448 alloy by the precipitation of a second phase from the nano-sized  matrix.

2010 ◽  
Vol 654-656 ◽  
pp. 2130-2133 ◽  
Author(s):  
Yu Lin Hao ◽  
Rui Yang

Ti2448 (Ti-24Nb-4Zr-8Sn wt.%) is a metastable  type titanium alloy developed recently for biomedical applications. The alloy possesses good biomechanical compatibility with human bone, in terms of high strength and an elastic modulus approaching that of the hard tissue of human body, as well as biochemical compatibility since it contains only nontoxic alloying elements. Bone plates manufactured from the Ti2448 alloy has undergone clinical trials and an application for product permission has been submitted to FDA of China. We review briefly the methodology of alloy design and peculiar properties including pronounced nonlinear elasticity and localized plastic deformation. Variations of mechanical properties with processing scheme will be presented. The positive effects of improved elastic matching between implant and bone on healing fractured bone are demonstrated by new bone formation at intramedullary nails implanted in New Zealand white rabbits and bone plates implanted in Beagle dogs.


Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1060
Author(s):  
Santiago Pinate ◽  
Caterina Zanella

This work explores the surface protection against wear provided by electroplated metal matrix composite coatings containing hard and lubricant particles. The second phase mix was selected to provide wear resistance by hardening the material and decreasing the friction coefficient. In this study, the capacity of providing wear protection by nano-SiC and self-lubrication by submicron graphite was addressed. Nickel-based composites with a dual powder mix of SiC 60 nm and graphite 400 nm, combined on a 10:10 g L−1 ratio, were produced by electrocodeposition. In addition, to better understand their synergy, mono-composites with SiC 60 nm or Graphite 400 nm with a powder load of 10 g L−1 were also produced. Pure nickel was also electrodeposited under the same conditions as a benchmark. Electron backscatter diffraction (EBSD) maps and chemical composition analysis were used to correlate the results from microhardness, wear resistance, and friction to the microstructure and particle incorporation rate. The wear rate tested by pin-on-disc decreased when the codeposition fraction and microhardness increased. Three main factors were determined to contribute to the coating hardness: Intrinsic hardness of the particle type, strengthening by grain refinement, and dispersion strengthening. The composites containing SiC provided the best wear protection due to the highest microhardness and grain refinement.


Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.


2021 ◽  
Vol 81 ◽  
pp. 13-25
Author(s):  
Diangeng Cai ◽  
Xiaotong Zhao ◽  
Lei Yang ◽  
Renxian Wang ◽  
Gaowu Qin ◽  
...  

2015 ◽  
Vol 1114 ◽  
pp. 3-8
Author(s):  
Nicolae Şerban ◽  
Doina Răducanu ◽  
Nicolae Ghiban ◽  
Vasile Dănuţ Cojocaru

The properties of ultra-fine grained materials are superior to those of corresponding conventional coarse grained materials, being significantly improved as a result of grain refinement. Equal channel angular pressing (ECAP) is an efficient method for modifying the microstructure by refining grain size via severe plastic deformation (SPD) in producing ultra-fine grained materials (UFG) and nanomaterials (NM). The grain sizes produced by ECAP processing are typically in the submicrometer range and this leads to high strength at ambient temperatures. ECAP is performed by pressing test samples through a die containing two channels, equal in cross-section and intersecting at a certain angle. The billet experiences simple shear deformation at the intersection, without any precipitous change in the cross-section area because the die prevents lateral expansion and therefore the billet can be pressed more than once and it can be rotated around its pressing axis during subsequent passes. After ECAP significant grain refinement occurs together with dislocation strengthening, resulting in a considerable enhancement in the strength of the alloys. A commercial AlMgSi alloy (AA6063) was investigated in this study. The specimens were processed for a number of passes up to nine, using a die channel angle of 110°, applying the ECAP route BC. After ECAP, samples were cut from each specimen and prepared for metallographic analysis. The microstructure of the ECAP-ed and as-received material was investigated using optical (OLYMPUS – BX60M) and SEM microscopy (TESCAN VEGA II – XMU). It was determined that for the as-received material the microstructure shows a rough appearance, with large grains of dendritic or seaweed aspect and with a secondary phase at grain boundaries (continuous casting structure). For the ECAP processed samples, the microstructure shows a finished aspect, with refined, elongated grains, also with crumbled and uniformly distributed second phase particles after a typical ECAP texture.


2021 ◽  
Vol 28 (7) ◽  
pp. 1112-1126
Author(s):  
Pan-jun Wang ◽  
Ling-wei Ma ◽  
Xue-qun Cheng ◽  
Xiao-gang Li

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1903 ◽  
Author(s):  
Yuhao Song ◽  
Mingtao Wang ◽  
Yaping Zong ◽  
Ri He ◽  
Jianfeng Jin

Based on the principle of grain refinement caused by the second-phase particles, a phase field model was built to describe the recrystallization process in the ZK60 alloy system with Y added under applied stress between temperatures 573 and 673 K for 140 min duration. The simulation of grain growth with second phase particles and applied stress during annealing process on industrial scale on the condition of real time-space was achieved. Quantitative analysis was carried out and some useful laws were revealed in ZK60 alloy system. The second phase particles had a promoting effect on the grain refinement, however the effect weakened significantly when the content exceeded 1.5%. Our simulation results reveal the existence of a critical range of second phase particle size of 0.3–0.4 μm, within which a microstructure of fine grains can be obtained. Applied stress increased the grain coarsening rate significantly when the stress was more than 135 MPa. The critical size of the second phase particles was 0.4–0.75 μm when the applied stress was 135 MPa. Finally, a microstructure with a grain size of 11.8–13.8 μm on average could be obtained when the second phase particles had a content of 1.5% and a size of 0.4–0.75 μm with an applied stress less than 135 Mpa after 30 min annealing at 573 K.


2015 ◽  
Vol 60 (2) ◽  
pp. 735-738 ◽  
Author(s):  
D. Klimecka-Tatar ◽  
S. Borkowski ◽  
P. Sygut

Abstract The main goal of the study was to carry out the treatment of cyclic oxidation of Ti alloy (Ti-1Al-1Mn) in air atmosphere. Based on measurements of mass gain of titanium alloy samples (Ti-1Al-1Mn) the kinetic oxidation curves during cyclic annealing were determined. The oxidized surface of the titanium alloy was carefully observed with optical microscopy equipment and the geometrical development, shape and surface morphology were defined. The phase composition of the obtained oxide layers on the Ti-alloy with qualitative analysis of the X-ray were defined. Since titanium alloys are among the most widely used metallic materials in dental prosthetics the corrosion measurements in a solution simulating the environment of the oral cavity were carried out. The results confirmed that the used titanium alloy easily covered with oxides layers, which to some extent inhibit the processes of electrochemical corrosion in artificial saliva solution.


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