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 Development of α+β-type biomedical Ti–Nb alloys with high oxygen content

2020 ◽  
Vol 321 ◽  
pp. 05003
Author(s):  
K. Ueda ◽  
M. Omiya ◽  
Y. Hirose ◽  
T. Narushima
Keyword(s):  
Oxygen Content ◽  
Low Cost ◽  
Total Elongation ◽  
Ti Alloy ◽  
High Oxygen Content ◽  
Β Phase ◽  
Α Phase ◽  
Heat Treated ◽  
Iced Water ◽  
Nb Content

Ti-(5–20)Nb-(0.5–1)O alloys (mass%) were investigated for developing low-cost biomedical α+β-type Ti alloy. Ti-(5, 10, 15, 20)Nb-(0.5, 0.75, 1)O alloys (mass%) were arc-melted and forged into bars. The forged alloy bars were heat-treated at 873 to 1373 K for 3.6 ks in an Ar atmosphere and quenched in iced water. β transus (Tβ) of the Ti-Nb-O alloys decreased with increasing Nb content. An increase in the oxygen content led to an increase in Tβ. After quenching, the formation of α′ martensite was observed in Ti-5Nb-yO alloys. An increase in the Nb content to 10 mass% led to the formation of α′ and α″ martensites. A further increase in the Nb content to 15 and 20mass% resulted in the formation of more α″ martensites. The boundary temperature for the formation of α′ and α″ martensite in the Ti-10Nb-yO alloys increased with increasing oxygen content, because oxygen enhances the Nb distribution to the β phase. The ultimate tensile strength of the Ti-xNb-0.75O alloys heattreated to obtain the α-phase fraction (fα) of 0.5 was over 1000 MPa, except for the Ti-15Nb-0.75O alloy. The total elongation decreased with increasing Nb content. The Ti-5Nb-0.75O alloy exhibited excellent strength-ductility balance as a low-cost α+β-type biomedical Ti alloy.

scholarly journals Correlation between the Microstructure and Mechanical Properties of W-Bearing Ti-6Al-4V Alloys

2021 ◽  
Vol 59 (6) ◽  
pp. 357-364
Author(s):  
Godwin Kwame Ahiale ◽  
In-Seok Kye ◽  
Young Sam Kwon ◽  
Yong-Jun Oh
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Solid Solution Hardening ◽  
Powder Injection ◽  
Injection Molding Process ◽  
Molding Process ◽  
Β Phase ◽  
Α Phase ◽  
The Matrix ◽  
Indentation Tests

W-containing Ti-6Al-4V alloys (W=0, 1, and 5 wt%) were fabricated by the powder injection molding process, and the corresponding effects of tungsten content on the mechanical properties and microstructure of the alloys were investigated. The alloy powders were sintered at 1200 °C and then hot-isostatically-pressed at 900 °C. The fabricated alloys were subjected to microstructural and chemical analyses, and tensile and nano-indentation tests. The yield strength and tensile strength proportionally increased as the W content was increased from 0 wt% to 5 wt%. Ductility was not affected by the addition of up to 5 wt% W due to its complete dissolution in the matrix. Higher W addition induced finer α/β lamellar microstructures and increased the β to α phase ratio. Moreover, the added W dissolved preferentially in the β phase by solid solution hardening, increasing the hardness of the β phase, which originally was significantly softer than the α phase. For the alloys containing up to 5 wt% W, the strengthening without ductility loss was attributed to the finer α/β lamellae and the volume increase in the β phase hardened by W. These results suggest that adding W to Ti-6Al-4V alloy is a promising method for developing Ti alloys with both high strength and toughness.

Mechanical Behaviors of Ti-29Nb-13Ta-4.6Zr-XO for Biomedical Applications Subjected to Cold Working and Various Heat Treatments

2007 ◽  
Vol 561-565 ◽  
pp. 1471-1476
Author(s):  
Mitsuo Niinomi ◽  
Toshikazu Akahori ◽  
Masaaki Nakai ◽  
Hiroshi Ishikawa ◽  
Michiharu Ogawa
Keyword(s):  
Elastic Modulus ◽  
Oxygen Content ◽  
Biomedical Applications ◽  
Cold Working ◽  
Early Stage ◽  
Age Hardening ◽  
Mechanical Behaviors ◽  
Ω Phase ◽  
Α Phase ◽  
Effect Of Oxygen

The effect of oxygen content on aging behavior and invar characteristics of Ti-29Nb-13Ta-4.6Zr (TNTZ) were investigated. The age hardening of TNTZ aged at 573 K and 723 K is enhanced with the oxygen content. The ω phase precipitates and grows from early stage of aging in TNTZ regardless of the oxygen content when aged at 573 K. The lath-like shape α phase precipitated in TNTZ aged at 723 K increases in size with the oxygen content. The elastic modulus increases with the oxygen content and aging. The ω phase increase the elastic modulus to a greater extent than the increase due to the α phase. The tensile strength increases with the oxygen content and aging, while the elongation decreases. TNTZ with oxygen content of 0.1 mass% exhibits invar-like characteristics through severe cold working. A higher oxygen content suppresses the invar-like characteristics of TNTZ.

Thermodynamic study at high temperature of the superconducting system YBa2Cu3Oz with 6

1987 ◽  
Vol 2 (6) ◽  
pp. 757-761 ◽  
Author(s):  
J. F. Marucco ◽  
C. Noguera ◽  
P. Garoche ◽  
G. Collin
Keyword(s):  
High Temperature ◽  
Large Deviations ◽  
Oxygen Content ◽  
Phase Stability ◽  
Stability Studies ◽  
Β Phase ◽  
Α Phase ◽  
Lower Oxygen ◽  
New Phase ◽  
Partial Oxygen

The YBa2Cu3Oz system has been investigated by thermogravimetry in a controlled partial oxygen pressure PO2 ranging from 105-10 Pa. A compound with z = 6.290 was prepared at T = 950°C and PO2 = 105 Pa and identified as a metastable β phase. Subsequent isothermal or isobar phase stability studies were performed. This β phase has a narrow metastability domain 6.25 <z < 6.50 at high temperature. By decreasing the temperature or increasing the PO2, the β phase transforms irreversibly into an α phase characterized by large deviations 7—x from stoichiometry. Near the stoichiometry z = 7, the structure of the a phase is orthorhombic, and fully ionized vacancies are likely to be predominant. By decreasing the PO2, the β phase transforms into a new phase with a lower oxygen content (z < 6.1).

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.

Effect of oxygen inclusion on microstructure and thermal stability of copper nitride thin films

2007 ◽  
Vol 22 (11) ◽  
pp. 3052-3057 ◽  
Author(s):  
Y. Du ◽  
R. Huang ◽  
R. Song ◽  
L.B. Ma ◽  
C. Liu ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Oxygen Content ◽  
Pure Copper ◽  
Decomposition Temperature ◽  
Copper Nitride ◽  
Oxygen Addition ◽  
Xrd Patterns ◽  
Effect Of Oxygen ◽  
A Minor

Copper oxynitride thin films with a minor oxygen content were prepared on silicon wafers at 100 °C by reactive magnetron sputtering using a gas mixture of nitrogen and oxygen. Addition of oxygen immediately improves the compactness of the deposits, which otherwise comprise ragged Cu3N nanocrystallites. With an oxygen content <10.0 at.%, the deposits reveal some sporadic Cu2O nanocrystals under transmission electron microscopy, but their x-ray diffraction (XRD) patterns exhibit reflections only from the Cu3N phase. The decomposition temperature, at which the sample after prolonged annealing shows Cu reflections on its XRD pattern, can be raised from 300 °C for stoichiometric Cu3N to 360 °C. The decomposition product after annealing at 450 °C is pure copper having an electrical resistivity of 8.94 × 10−8 Ω·m at room temperature, which can be taken as a good conductor and stands in strong contrast with the oxynitride matrix with an electrical resistivity of 6.87 × 10−2 Ω·m. These results constitute progress in the search of directly writable copper nitride-based materials.

Role of Interstitial Oxygen Atom on Martensitic Transformation of Ti-Nb Alloy

2016 ◽  
Vol 97 ◽  
pp. 115-118
Author(s):  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Hee Young Kim ◽  
Shuichi Miyazaki ◽  
Hideki Hosoda
Keyword(s):  
Martensitic Transformation ◽  
Oxygen Content ◽  
Martensite Phase ◽  
Interstitial Oxygen ◽  
Scanning Calorimetry ◽  
Martensite Stabilization ◽  
Oxygen Addition ◽  
The Stability ◽  
Effect Of Oxygen

The effect of oxygen content on the stability of α′′ martensite phase of the Ti-20mol%Nb alloy was investigated by differential scanning calorimetry. The reverse martensitic transformation temperature increased with increasing oxygen content, and this means that α′′ martensite phase was stabilized by oxygen addition. The mechanism of α′′ martensite stabilization by oxygen atoms was discussed based on the changes in the lattice parameters of α′′ martensite.

The Effect of Oxygen Concentration on Ignition of Fuel Spray in Low-Pressure Air Flow

1985 ◽  
Vol 107 (1) ◽  
pp. 18-23
Author(s):  
Y. H. Zhao ◽  
N. K. Chen ◽  
J. S. Chin
Keyword(s):  
Oxygen Concentration ◽  
Low Pressure ◽  
Fuel Spray ◽  
Thermal Ignition ◽  
Oxygen Injection ◽  
Stagnant Region ◽  
Oxygen Addition ◽  
Effect Of Oxygen ◽  
Ignition Improvement ◽  
Local Oxygen

Further experimental research has been carried out on the ignition improvement by oxygen addition in a small pilot combustion chamber taken from an existing aeroengine. Both uniform mixture method and local oxygen injection method have been investigated. The results show that oxygen addition improves low-pressure ignition performance significantly. Local oxygen injection makes much better use of oxygen added. Experimental results show low evaporation percentage of fuel spray responsible for the poor ignition performance. Based on thermal ignition theory, a semianalytical equation has been obtained to predict the relative enlargement of maximum ignition velocity by oxygen addition, the equation can correlate experimental data very well. To form a stagnant region with suitable oxygen concentration is the most important factor in the design of ignitor with oxygen addition.

scholarly journals Effect of oxygen addition on the formation of isothermal ω phase in Ti-Fe alloys

2020 ◽  
Vol 321 ◽  
pp. 12033
Author(s):  
Sengo Kobayashi ◽  
Shota Sasaki ◽  
Sota Kawano ◽  
Renta Sasaki ◽  
Satoshi Okano
Keyword(s):  
Thermal Analysis ◽  
Room Temperature ◽  
Optical Microscope ◽  
Disk Specimen ◽  
Β Phase ◽  
Ω Phase ◽  
Fe Alloys ◽  
Oxygen Addition ◽  
Effect Of Oxygen ◽  
Hot Rolled

The effect of the addition of oxygen on the formation of microstructure cooled from the β phase of Ti-Fe alloy was examined. The alloy ingots of Ti-(4, 5, 6, 7, 8, 9 and 10) at.% Fe and Ti-8 at.% Fe-(1 and 3) at.% O were arc-melted. They were homogenized at 1200 °C for 3.6 ks and then hot-rolled at 850 °C into 1.5-mm thick sheets. The disk specimen was fabricated and then put in the differential thermal analysis (DTA) apparatus. The disk in the DTA was heated at 1000 °C for 0.6 ks in the β phase and then cooled to room temperature at a rate of 50 °C/min. The microstructure was examined by an optical microscope after the DTA experiment. In the Ti-(7 and 8) Fe alloys the ω phase formed during cooling. The addition of oxygen in the Ti-8Fe alloy promoted the β→α transformation. Furthermore, the addition of one at.% oxygen in the Ti-8Fe alloy promoted β→ωi transformation, while the addition of three at.% oxygen suppressed the β→ωi transformation during cooling.

The Effect of Oxygen Concentration on Ignition of Fuel Spray in Low Pressure Air Flow

1984 ◽  
Author(s):  
Y. H. Zhao ◽  
N. K. Chen ◽  
J. S. Chin
Keyword(s):  
Oxygen Concentration ◽  
Low Pressure ◽  
Fuel Spray ◽  
Oxygen Injection ◽  
Stagnant Region ◽  
Aero Engine ◽  
Oxygen Addition ◽  
Effect Of Oxygen ◽  
Ignition Improvement ◽  
Local Oxygen

Further experimental research has been carried out on the ignition improvement by oxygen addition in a small pilot combustion chamber taken from an existing aero-engine. Both uniform mixture method and local oxygen injection method have been investigated. The results show that oxygen addition improves low pressure ignition performance significantly. Local oxygen injection makes much better use of oxygen added. Experimental results show low evaporation percentage of fuel spray responsible for the poor ignition performance. Based on thermal ignition theory, a semi-analytical equation has been obtained to predict the relative enlargement of maximum ignition velocity by oxygen addition, the equation can correlate experimental data very well. To form a stagnant region with suitable oxygen concentration is the most important factor in the design of ignitor with oxygen addition.

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