The Effect of Oxygen on the Phase Composition and Heat Treatment Behavior of Ti-V Alloys

2018 ◽  
Vol 941 ◽  
pp. 1565-1569
Author(s):  
Hitomi Nagasawa ◽  
Masahiko Ikeda ◽  
Masato Ueda
Keyword(s):  
Heat Treatment ◽  
Electrical Resistivity ◽  
Vickers Hardness ◽  
Low Cost ◽  
Solid Solution Hardening ◽  
Specific Strength ◽  
Β Phase ◽  
Solution Treated ◽  
Good Biocompatibility ◽  
Effect Of Oxygen

Titanium and its alloys possess high specific strength, excellent corrosion resistance and good biocompatibility [1] [2]. Since oxygen is an unavoidable impurity in such materials, it has been adopted as an alloying element in the development of low-cost titanium alloys. Therefore, it is important to investigate the role of oxygen in these alloys, especially in β-type alloys. In the present study, the effects of oxygen on the electrical resistivity, Vickers hardness and heat treatment behavior of a Ti-20mass%V alloy which is the lowest concentration for which the fully retained β phase is obtained were assessed. The electrical resistivity and Vickers hardness of solution-treated and quenched specimens increased with increasing oxygen content, due to the dissolution of oxygen into the β phase and solid solution hardening, respectively. Upon isothermal aging at 673 K, the addition of O accelerated a-phase precipitation. The addition of O was found to suppress the appearance of the athermal ω phase in the solution-treated and quenched state.

Phase Constitution and Heat Treatment Behavior of Low Cost Ti-Mn System Alloys

2013 ◽  
Vol 551 ◽  
pp. 217-222 ◽  
Author(s):  
Masahiko Ikeda ◽  
Masato Ueda ◽  
Kaoru Imaizumi ◽  
Mitsuo Niinomi
Keyword(s):  
Heat Treatment ◽  
Titanium Alloys ◽  
Low Cost ◽  
Metallic Elements ◽  
X Ray Diffraction ◽  
Phase Constitution ◽  
Specific Strength ◽  
Good Biocompatibility ◽  
Fe Alloys ◽  
The Cost

This paper is a review of results for Ti-Mn [1], Ti-Mn-Al [2] and Ti-Mn-Fe [3] alloys that have been previously published. Titanium alloys, especially beta-type titanium alloys, have high specific strength, excellent corrosion resistance and good biocompatibility. Unfortunately, applications of titanium alloys are limited by their relatively higher cost. One reason is the use of rare and expensive metallic elements, such as vanadium and molybdenum, as a beta stabilizer. In order to reduce the cost, inexpensive and abundantly available metallic elements should be used as beta stabilizers. Manganese was adopted as a beta stabilizer because it is an abundant metallic element in the Earth’s crust and is relatively low in cost. The heat treatment behavior of Ti-Mn, Ti-Mn-Al and Ti-Mn-Fe alloys was investigated through electrical resistivity and Vickers hardness measurements, X-ray diffraction measurements to identify phase constitution, and observations using a light microscope [1], [2] and [3].

Influence of Substitution of Fe by Mo on Heat Treatment Behavior in Ti-Mo-Fe Alloys

2021 ◽  
Vol 1016 ◽  
pp. 162-169
Author(s):  
Kyosuke Mizuta ◽  
Shotaro Miyake ◽  
Masahiko Ikeda ◽  
Masato Ueda
Keyword(s):  
Heat Treatment ◽  
Electrical Resistivity ◽  
Diffusion Coefficient ◽  
Vickers Hardness ◽  
Partial Substitution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Ti Alloys ◽  
Fe Alloys

In order to reduce the cost of β-type Ti alloys, the use of Fe as an alloying element has been studied. However, Fe is known to have a very high diffusion coefficient in β-Ti of about 2.6×10-12 m2/s at 1200 K, and its behavior during heat treatment is expected to be difficult to control. By contrast, Mo, which is also a β-stabilizing element, has a diffusion coefficient of only about 2.5×10-14 m2/s at 1200 K, i.e., roughly 100 times smaller than that of Fe1), 2). In this study, the effect of the partial substitution of Fe with Mo on the aging behavior of β-Ti alloys was investigated using X-ray diffraction, electric resistivity, and Vickers hardness measurements. Ti-Mo-Fe alloys were solution-treated by holding at 1173 K for 3.6 ks and then quenching in ice water. In the X-ray diffraction patterns for the resulting samples, only peaks associated with the β phase were identified. It was found that the electrical resistivity and Vickers hardness decreased with increasing Mo content. As the Mo-to-Fe ratio increased, the decrease in electrical resistivity and the increase in Vickers hardness occurred later during the isothermal aging process. This was due to a delay in isothermal ω-phase precipitation.

Development and Research of Low-Cost Titanium Alloys, Especially Case of Japan

2016 ◽  
Vol 879 ◽  
pp. 119-124 ◽  
Author(s):  
Masahiko Ikeda ◽  
Masato Ueda
Keyword(s):  
Heat Treatment ◽  
Vickers Hardness ◽  
Low Cost ◽  
Beta Phase ◽  
Omega Phase ◽  
X Ray Diffraction ◽  
Practical Applications ◽  
Al Content ◽  
Ti Alloys ◽  
Fe Alloys

Titanium (Ti) exhibits many attractive properties that enable practical applications. It is also considered to be a ubiquitous element, since it has the ninth highest Clarke number among all the elements. However, the principal beta-stabilizing elements for Ti, molybdenum and vanadium, can be very expensive, and so many Ti alloys are also costly. For this reason, less expensive alloying elements would be preferable. Iron (Fe) and manganese (Mn) are beta stabilizers for Ti alloys that are readily available, since they have the fourth and eleventh highest Clarke numbers, respectively. Furthermore, since Fe has a large diffusion coefficient in the beta phase of Ti, precipitation of the omega phase occurs more quickly when Fe is added. The behaviors of Ti-Mn and Mn-Fe alloys during heat treatment have been investigated and it has been found that, in some alloys, the isothermal omega phase is precipitated. Because this phase can lead to brittleness of the alloy, it is very important to suppress its precipitation. Since it is well known that aluminum (Al) suppresses isothermal omega precipitation, the present work investigated the effects of Al content on the phase constitution and heat treatment behavior of Ti-8.5 mass%Mn-1 mass%Fe-0, 1.5, 3.0 and 4.5 mass%Al alloys using electrical resistivity, Vickers hardness, and X-ray diffraction measurements. In the case of each of these alloys, whether solution-treated or water-quenched, only the beta phase was identified. The resistivities at room and liquid nitrogen temperatures were found to increase monotonically with Al content, while the Vickers hardness decreased up to 3 mass% Al and then remained constant. The addition of Al was found to suppress omega precipitation.

Effect of Zr-Addition to Ti-14Mn Alloy

2017 ◽  
Vol 890 ◽  
pp. 352-355
Author(s):  
Mohammed K. Gouda ◽  
Mohamed Abdel Hady Gepreel ◽  
Koichi Nakamura ◽  
Akihiko Chiba
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Low Cost ◽  
Alloy System ◽  
Arc Melting ◽  
Solution Treated ◽  
Zr Addition ◽  
Cold Rolled ◽  
Cold Workability

The effect of Zr addition on the microstructure, cold workability and hardness of low-cost Ti-14Mn alloy was investigated. A set of alloys with1.5, 3 and6%wt. Zr were produced by arc melting. The alloys were subjected to solution heat treatment at 900 °C.Zr seems working as weak β-stabilizer in this Ti-14Mn-xZr alloy system. The effect of Zr-content on the cold workability was assessed.The cold workability of the Ti-14Mn-xZr alloys (withZr up to 6%) is higher than 90% reduction ration. The hardness slightly increased with the increase ofZr-content in Ti-14Mn-xZr alloys in both solution treated and cold rolled conditions.

Phase Constitution and Heat Treatment Behavior of Zr-Nb Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 1435-1440 ◽  
Author(s):  
Masahiko Ikeda ◽  
Tsuyoshi Miyazaki ◽  
Satoshi Doi ◽  
Michiharu Ogawa
Keyword(s):  
Heat Treatment ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
X Ray Diffraction ◽  
Phase Constitution ◽  
X Ray ◽  
Β Phase ◽  
Ω Phase ◽  
Solution Treated ◽  
Α Phase

Phase constitution in the solution-treated and quenched state and the heat treatment behavior were investigated by electrical resistivity, hardness, and elastic modulus measurements, X-ray diffraction, and optical microscopy. Hexagonal martensite and the β phase were identified in the Zr-5mass%Nb alloy. β and ω phases were identified in the Zr-10 and 15mass%Nb alloys, and only the β phase was identified in the Ti-20Nb alloy. Resistivity at RT, Vickers hardness and elastic modulus increased up to 10Nb and then decreased dramatically at 15Nb. Above 15Nb, these values slightly decreased. The elastic moduli for 15Nb and 20Nb were 59.5 and 55.5 GPa, respectively. On isochronal heat treatment, the isothermal ω phase precipitated between 473 and 623 K and then the α phase precipitated in the 10Nb, 15Nb and 20Nb alloys.

The Effect of Oxygen on Heat Treatment Behavior of Titanium-50mass%Tantalum-5mass%Zirconium Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3613-3618
Author(s):  
Masahiko Ikeda ◽  
Masaaki Mori
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Shape Recovery ◽  
Liquid Nitrogen Temperature ◽  
X Ray Diffraction ◽  
Resistivity Ratio ◽  
Orthorhombic Martensite ◽  
Β Phase ◽  
Heat Treated ◽  
Effect Of Oxygen

To develop new shape memory and super-elastic alloys for medical applications, titanium alloys using non-toxic metallic elements, such as Ta and Nb, are being actively investigated. In this study, aimed at developing new shape memory Ti alloys, we investigate the effect of oxygen, a powerful alpha stabilizing interstitial element, on the heat treatment behavior of Ti-50mass%Ta-5mass%Zr through electrical resistivity and Vickers hardness measurements and shape-recovery tests. Ti-50Ta-5Zr-0.14Ox and 0.33Ox alloys, and the β and α” bi-phase was confirmed by XRD. Only the β phase was identified in the Ti-50Ta-5Zr-0.62Ox alloy. Upon isochronal heat treatment, the resistivity at LN and resistivity ratio of Zr-0.33 and 0.62Ox alloys decreased up to around 523 K. In the 5Zr-0.62Ox alloy, orthorhombic martensite and the α” and β phases were identified in the specimens heat-treated at 473 and 523 K. The decreases in resistivity at liquid nitrogen temperature and resistivity ratio are due to the formation of α” during isochronal heat treatment. The formation of α” was confirmed by X-ray diffraction in the 5Zr-0.62Ox alloy. The shape memory effect was observed in 5Zr-0.14 and 0.33Ox alloys and the shape recovery ratio of both alloys was about 40% at 673 K.

Formation of 14H-type long period stacking ordered structure in the as-cast and solid solution treated Mg–Gd–Zn–Zr alloys

2009 ◽  
Vol 24 (5) ◽  
pp. 1842-1854 ◽  
Author(s):  
W.J. Ding ◽  
Y.J. Wu ◽  
L.M. Peng ◽  
X.Q. Zeng ◽  
G.Y. Yuan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Solution Heat Treatment ◽  
Ordered Structure ◽  
Long Period ◽  
Β Phase ◽  
Solution Treated ◽  
Lpso Structure ◽  
Temperature Transformation ◽  
Zr Alloys

The coherent fine lamellae consisting of the 2H-Mg and the 14H-type long period stacking ordered (LPSO) structure within α′-Mg matrix have been first observed in an as-cast Mg96.32Gd2.5Zn1Zr0.18 alloy. During subsequent solid solution heat treatment at 698–813 K, in addition to the lamellae within matrix, a novel lamellar X phase (Mg–8.37±1.0Zn–11.32±1.0Gd, at.%) with the 14H-type LPSO structure was transformed from the dendritical β phase, and a corresponding time–temperature–transformation (TTT) diagram was established. The 14H-type LPSO structure existing in Mg–Gd–Zn–Zr alloys derives from two variant means: the formation of LPSO structure within α′-Mg matrix and the transformation of the dendritical β phase to a lamellar X phase with the LPSO structure. The alloy solid solution treated at 773 K for 35 h exhibits higher tensile strength and better elongation than the nonheated alloy because of the lamellar X phase with the 14H-type LPSO structure and the 14H-type LPSO structure within matrix.

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.

Influence of Oxygen on Microstructures of Ti-Mo-Cr Alloy

2014 ◽  
Vol 896 ◽  
pp. 613-616 ◽  
Author(s):  
Junaidi Syarif ◽  
Eko Kurniawan ◽  
Mohd Rasidi Rasani ◽  
Zainuddin Sajuri ◽  
Mohd Zaidi Omar ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Oxygen Concentration ◽  
Solid Solution Hardening ◽  
Stable Phase ◽  
Powder Metallurgy Method ◽  
Β Phase ◽  
Α Phase ◽  
Phase Calculation ◽  
Oxygen Addition ◽  
Effect Of Oxygen

In this study, the effect of oxygen addition on the microstructures of Ti-18%Mo-10%Cr alloy was investigated. The alloy was fabricated by a powder metallurgy method. The samples were subjected to sintering at 1300°C for 4 hours and furnace cooling. A Bo-Md method was initially applied for predicting stable phase. Calculation using the Bo-Md method showed that Ti-18%Mo-10%Cr alloy have bcc (β) phase at ambient temperature. All samples with various oxygen contents exhibited needle-like structures within equiaxed grains. The increase of oxygen content promoted formation of porosity in the α phase. Calculation of phase stability using JMatProTM showed that the decrease of β phase’s stability was not due to formation of the α phase on sintering, but due to promotion of nucleation and grain growth of diffusional α phase upon furnace cooling. It was also shown that vol.% of porosity of the alloy slightly increased with increasing oxygen content. Therefore, the increase of oxygen concentration could accelerate the formation of α phase and reduce the alloy’s density. The hardness increased as the oxygen concentration increased. The increase of the hardness might be due to combination of the solid solution hardening of oxygen and the precipitation hardening of α phase.

scholarly journals Extremely rapid age hardening behavior in solution treated Ti-5Al-2Fe-3Mo

2020 ◽  
Vol 321 ◽  
pp. 11016
Author(s):  
Tomonori KUNIEDA ◽  
Hideki FUJII ◽  
Kazuhiro TAKAHASHIa
Keyword(s):  
Phase Transformation ◽  
Vickers Hardness ◽  
Martensite Transformation ◽  
Solution Treatment ◽  
Age Hardening ◽  
Time Dependency ◽  
Β Phase ◽  
Eds Analysis ◽  
Solution Treated ◽  
Initial Stage

To grasp age hardening and phase transformation behaviors in a β rich α+β type titanium alloy, Ti-5Al-2Fe-3Mo, during aging at 300-500°C after the solution treatment at high α+β temperature. Vickers hardness and microstructure changes during aging were closely investigated using XDR and TEM/EDS. Vickers hardness rapidly increased with increasing holding time and reached about 440HV by aging at 450°C for only 5 min. It further increased to 510HV in 8h of aging time. The initial stage of age hardening is extremely fast compared to that in other conventional α+β and β type titanium alloys. After aging for only 5min, extremely fine acicular products of about 2 to 10 nm in width were formed in the transformed β phase. TEM/EDS analysis revealed that all substitutional alloying elements, Al, Fe and Mo, homogeneously distributed after the aging, indicating that the transformation is diffusionless as far as substitutional elements are concerned just like martensite transformation although it has time dependency. To explain the mechanism of this unique phase transformation having features of isothermal martensite transformation, we propose bainitic transformation where interstitials such as O diffuse without conspicuous diffusion of substitutional elements.

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