scholarly journals First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Group Vi ◽  
Group V ◽  
Β Phase ◽  
Ti Alloys ◽  
Ω Phase ◽  
Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

Phase Stability and Mechanical Properties of Ti-Cr Based Alloys with Low Young’s Modulus

2010 ◽  
Vol 654-656 ◽  
pp. 2114-2117 ◽  
Author(s):  
Yonosuke Murayama ◽  
Shuichi Sasaki ◽  
Hisamichi Kimura ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Phase Stability ◽  
Deformation Mechanism ◽  
Young's Modulus ◽  
Deformation Behaviour ◽  
System Alloy ◽  
Β Phase ◽  
Ω Phase ◽  
Cr System

This work investigates the mechanical properties of Ti-Cr system alloys and focuses on the microstructure, the Young’s modulus, the deformation mechanism and the deformation behaviour observed in various alloy compositions. The addition of Al to the Ti-Cr system alloys greatly decreases the Young’s modulus. Addition of Al, Sn and Zr to various Ti-Cr alloys suppresses the athermal ω phase that forms during quenching from β field. A Ti-Cr system alloy with low Young’s modulus was obtained in suitable compositional combination of Cr, Zr and Sn or Al. The alloys with the composition where the quenched microstructure transits from martensite to meta-stable β phase show low Young’s modulus. In addition, the alloys show two-step yielding due to stress-induced transformation.

Fabrication of Titanium / Biodegradable-Polymer FGM for Medical Application

2009 ◽  
Vol 631-632 ◽  
pp. 199-204 ◽  
Author(s):  
Yoshimi Watanabe ◽  
Yoshimi Iwasa ◽  
Hisashi Sato ◽  
Akira Teramoto ◽  
Koji Abe
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Medical Application ◽  
Hot Water ◽  
Porous Ti ◽  
Ti Alloys ◽  
Plasma Sintering ◽  
Biodegradable Poly ◽  
Spark Plasma

Ti and Ti alloys are widely used as metallic implants, because of their good mechanical properties and nontoxic behavior. However, they have problems as the implant-materials, namely, high Young’s modulus comparing that of bone and low bonding ability with bone. There is a need to develop the Ti and Ti alloys with lower Young’s modulus and good bonding ability. In previous study, Ti composite containing biodegradable poly-L-lactic-acid (PLLA) fiber has been fabricated to improve these problems. However, this composite has low strength because of the imperfect sintering of Ti matrix. To improve its strength, sintering of Ti matrix should be completed. In this study, Ti-NaCl composite material was fabricated by spark plasma sintering (SPS) method using powder mixture of Ti and NaCl to complete the sintering of Ti matrix. To obtain porous Ti samples, Ti-NaCl composite were put into hot water of 100 oC. The porous Ti was dipped into PLLA melt in order to introduce PLLA into the pores of porous Ti. Finally, Ti-PLLA composite was obtained, and PLLA plays a role as reinforcement of Ti matrix. It was found that the Ti-PLLA composite has gradient structure and mechanical properties.

Effects of Cooling Rate and Sn Addition on the Microstructure of Ti-Nb-Sn Alloys

2011 ◽  
Vol 172-174 ◽  
pp. 190-195 ◽  
Author(s):  
Giorgia T. Aleixo ◽  
Eder S.N. Lopes ◽  
Rodrigo Contieri ◽  
Alessandra Cremasco ◽  
Conrado Ramos Moreira Afonso ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Melting Furnace ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Β Phase ◽  
Arc Melting ◽  
Ti Alloys ◽  
Ω Phase

Ti-based alloys present unique properties and hence, are employed in several industrial segments. Among Ti alloys, β type alloys form one of the most versatile classes of materials in relation to processing, microstructure and mechanical properties. It is well known that heat treatment of Ti alloys plays an important role in determining their microstructure and mechanical behavior. The aim of this work is to analyze microstructure and phases formed during cooling of β Ti-Nb-Sn alloy through different cooling rates. Initially, samples of Ti-Nb-Sn system were prepared through arc melting furnace. After, they were subjected to continuous cooling experiments to evaluate conditions for obtaining metastable phases. Microstructure analysis, differential scanning calorimetry and X-ray diffraction were performed in order to evaluate phase transformations. Depending on the cooling rate and composition, α” martensite, ω phase and β phase were obtained. Elastic modulus has been found to decrease as the amount of Sn was increased.

Phase Stability and Mechanical Properties of Ti-Cr-Sn-Zr Alloys Containing a Large Amount of Zr

2016 ◽  
Vol 879 ◽  
pp. 1344-1349 ◽  
Author(s):  
Yonosuke Murayama ◽  
Erdnechuluun Enkhjavkhlan ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Deformation Behavior ◽  
Single Phase ◽  
Young's Modulus ◽  
Martensitic Structure ◽  
Β Phase ◽  
Microstructural Transition ◽  
Zr Alloy ◽  
Zr Alloys

The Young’s modulus of Ti-Cr-Sn-Zr alloy varies with the composition of Cr, Sn and Zr, in which the elements act as β stabilizers. Some Ti-Cr-Sn-Zr alloys show very low Young’s modulus under 50GPa. The amount of Zr in alloys with very low Young's modulus increases with the decrease of Cr. We investigated the Young’s modulus and deformation behavior of Ti-xCr-Sn-Zr (x=0~1mass%) alloys containing a large amount of Zr. The quenched microstructure of Ti-Cr-Sn-Zr alloys changes from martensitic structure to β single-phase structure if the amounts of β stabilized elements are increased. The Ti-Cr-Sn-Zr alloys with compositions close to the transitional composition of microstructure from martensite to β phase show minimum Young’s modulus. The clear microstructural transition disappears and the minimum Young’s modulus increases if the amount of Cr becomes too small. In Ti-Cr-Sn-Zr alloys containing a large amount of Zr, Young’s modulus depends on β phase that is intermingled with martensite.

Mechanical Properties of Ti-Cr-Sn-Zr Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 635-640 ◽  
Author(s):  
Yonosuke Murayama ◽  
Shuichi Sasaki ◽  
Hisamichi Kimura ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Biomedical Application ◽  
Young's Modulus ◽  
Mechanical Twinning ◽  
Β Phase ◽  
Low Modulus ◽  
Deformation Modes ◽  
Zr Alloy ◽  
Zr Alloys

Low modulus β Ti alloys are attractive for biomedical application. This work examines the mechanical properties of Ti-Cr-Sn-Zr system alloys, especially the effect of the varying alloy composition on the microstructure, the Young’s modulus and the deformation mechanism.The Young’s modulus of the alloy varies with the composition, which variation is caused mainly from the competition between the meta-stable β phase and ω phase.The deformation modes of the Ti-Cr-Sn-Zr alloy, which are the mechanical twinning, the deformation by slip and the deformation-induced transformation, also change depending on the composition of the alloy. The minimum of the Young’s modulusof the Ti-Cr-Sn-Zr alloy in this experiment was shown in the composition where the microstructure of the alloy changes from the martensitic structure to the meta-stable β structure.

Mechanical Properties of Transparent Polycrystalline Silicon Nitride

2006 ◽  
Vol 317-318 ◽  
pp. 305-308 ◽  
Author(s):  
Rak Joo Sung ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Yoon Ho Kim ◽  
Tohru Sekino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Polycrystalline Silicon ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Β Phase ◽  
Α Phase

A novel transparent polycrystalline silicon nitride was fabricated by hot-press sintering with MgO and AlN as additives. The mixed powder with 3 wt.% MgO and 9 wt.% AlN was sintered at 1900oC for 1 hour under 30 MPa pressure in a nitrogen gas atmosphere. Transparent polycrystalline silicon nitride was successfully fabricated. The mechanical properties such as density, hardness, young’s modulus, fracture strength and fracture toughness were evaluated. The effect of α/β phase on the mechanical properties of transparent polycrystalline silicon nitride was investigated. The properties were changed depending on the amount of α/β phase. The hardness and Young's modulus increased with increasing the volume fraction of α-phase fraction as a reflection of the higher hardness of α-phase Si3N4. The fracture toughness and fracture strength decreased with decreasing the volume fraction of β-phase Si3N4.

scholarly journals Improving the Mechanical Properties of a β-type Ti-Nb-Zr-Fe-O Alloy

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1491 ◽  
Author(s):  
Vasile Danut Cojocaru ◽  
Anna Nocivin ◽  
Corneliu Trisca-Rusu ◽  
Alexandru Dan ◽  
Raluca Irimescu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Research Directions ◽  
Biomedical Implant ◽  
Advantages And Disadvantages ◽  
Β Phase

The influence of complex thermo-mechanical processing (TMP) on the mechanical properties of a Ti-Nb-Zr-Fe-O bio-alloy was investigated in this study. The proposed TMP program involves a schema featuring a series of severe plastic deformation (SPD) and solution treatment (STs). The purpose of this study was to find the proper parameter combination for the applied TMP and thus enhance the mechanical strength and diminish the Young’s modulus. The proposed chemical composition of the studied β-type Ti-alloy was conceived from already-appreciated Ti-Nb-Ta-Zr alloys with high β-stability by replacing the expensive Ta with more accessible Fe and O. These chemical additions are expected to better enhance β-stability and thus avoid the generation of ω, α’, and α” during complex TMP, as well as allow for the processing of a single bcc β-phase with significant grain diminution, increased mechanical strength, and a low elasticity value/Young’s modulus. The proposed TMP program considers two research directions of TMP experiments. For comparisons using structural and mechanical perspectives, the two categories of the experimental samples were analyzed using SEM microscopy and a series of tensile tests. The comparison also included some already published results for similar alloys. The analysis revealed the advantages and disadvantages for all compared categories, with the conclusions highlighting that the studied alloys are suitable for expanding the database of possible β-Ti bio-alloys that could be used depending on the specific requirements of different biomedical implant applications.

A METALLURGICAL OVERVIEW OF TI – BASED ALLOY IN BIOMEDICAL APPLICATIONS

2015 ◽  
Vol 76 (7) ◽  
Author(s):  
Nur Hidayatul Nadhirah Elmi Azham Shah ◽  
Mazyan Yahaya ◽  
Maheran Sulaiman ◽  
Muhammad Hussain Ismail
Keyword(s):  
Young’S Modulus ◽  
Biomedical Application ◽  
Young's Modulus ◽  
Stress Shielding ◽  
Young Modulus ◽  
Processing Technique ◽  
Shielding Effect ◽  
Β Phase ◽  
Ti Alloys ◽  
Α Phase

Titanium (Ti)-based alloys are prominently used in biomedical application. This review paper emphasizes on some of the important aspects of the Ti-alloys in terms of metallurgical aspects, manufacturing routes and biocompatibility. Two kinds of structure are reviewed namely dense and porous, both differs in terms of purpose and satisfies different needs. This advancement of materials and equipment helps to improve the quality of life for patients and alleviate their health problems. Metallic materials, mainly Ti-based alloys have been used commercially as bone implant owing to its promising mechanical properties, biocompatibility and bioactivity. The outmost important issue in manufacturing  of  this  alloy  is  the  impurity  contents,  specifically  oxygen  and  carbon  which contribute   to decreasing in material performance of the alloy attributed from the formation of unwanted  oxide compounds such as TiO2 and  TiC. Another issue is the mismatch value of the Young’s modulus between the metallic implant and bone that result in stress shielding effect.  The structure of Ti-based  alloy is  mainly comprised of α-phase, β-phase or a combination of  both that result in variation of Young’s modulus ranging from 45 -110 GPa. Compared to α-phase Ti alloy, the β-phase rich alloys may exhibit lower value of Young modulus through the right processing technique. Therefore, the development of β-phase Ti-alloys has been researched progressively in line with the need of low Young’s modulus that suit for implant applications.

Structure, Microstructure, and Selected Mechanical Properties of Ti-Zr-Mo Alloys for Biomedical Applications

2014 ◽  
Vol 922 ◽  
pp. 75-80 ◽  
Author(s):  
Diego Rafael Nespeque Correa ◽  
Pedro Akira Bazaglia Kuroda ◽  
Carlos Roberto Grandini
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Young's Modulus ◽  
Microstructural Analysis ◽  
Melting Furnace ◽  
High Hardness ◽  
Mechanical Analysis ◽  
Β Phase

New titanium alloys for biomedical applications have been developed primarily with the addition of Nb, Ta, Mo, and Zr, because those elements stabilize the β phase and they don’t cause cytotoxicity in the organism. The objective of this paper is to analyze the effect of molybdenum on the structure, microstructure, and selected mechanical properties of Ti-15Zr-xMo (x = 5, 10, 15, and 20 wt%) alloys. The samples were produced in an arc-melting furnace with inert argon atmosphere, and they were hot-rolled and homogenized. The samples were characterized using chemical, structural, and microstructural analysis. The mechanical analysis was made using Vickers microhardness and Young’s modulus measurements. The compositions of the alloys were sensitive to the molybdenum concentration, indicating the presence of α’+α”+β phases in the Ti-15Zr-5Mo alloy, α”+β in the Ti-15Zr-10Mo alloy, and β phase in the Ti-15Zr-15Mo and Ti-15Zr-20Mo alloys. The mechanical properties showed favorable values for biomedical application in the alloys presenting high hardness and low Young’s modulus compared with CP-Ti.

scholarly journals Ti–Zr–Si–Nb Nanocrystalline Alloys and Metallic Glasses: Assessment on the Structure, Thermal Stability, Corrosion and Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1551
Author(s):  
Camelia Gabor ◽  
Daniel Cristea ◽  
Ioana-Laura Velicu ◽  
Tibor Bedo ◽  
Andrea Gatto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Titanium Alloys ◽  
Young’S Modulus ◽  
Melt Spinning ◽  
Young's Modulus ◽  
Structural Features ◽  
Input Power ◽  
X Ray ◽  
Β Phase

The development of novel Ti-based amorphous or β-phase nanostructured metallic materials could have significant benefits for implant applications, due to improved corrosion and mechanical characteristics (lower Young’s modulus, better wear performance, improved fracture toughness) in comparison to the standardized α+β titanium alloys. Moreover, the devitrification phenomenon, occurring during heating, could contribute to lower input power during additive manufacturing technologies. Ti-based alloy ribbons were obtained by melt-spinning, considering the ultra-fast cooling rates this method can provide. The titanium alloys contain in various proportions Zr, Nb, and Si (Ti60Zr10Si15Nb15, Ti64Zr10Si15Nb11, Ti56Zr10Si15Nb19) in various proportions. These elements were chosen due to their reported biological safety, as in the case of Zr and Nb, and the metallic glass-forming ability and biocompatibility of Si. The morphology and chemical composition were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy, while the structural features (crystallinity, phase attribution after devitrification (after heat treatment)) were assessed by X-ray diffraction. Some of the mechanical properties (hardness, Young’s modulus) were assessed by instrumented indentation. The thermal stability and crystallization temperatures were measured by differential thermal analysis. High-intensity exothermal peaks were observed during heating of melt-spun ribbons. The corrosion behavior was assessed by electrocorrosion tests. The results show the potential of these alloys to be used as materials for biomedical applications.

Sign in / Sign up

Export Citation Format

Share Document