Direct reduction of upgraded titania slag by magnesium for making low-oxygen containing titanium alloy hydride powder

2020 ◽  
Vol 368 ◽  
pp. 160-169
Author(s):  
Zhaowang Dong ◽  
Yang Xia ◽  
Xueyi Guo ◽  
Jinlong Zhao ◽  
Linfeng Jiang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Direct Reduction ◽  
Low Oxygen ◽  
Titania Slag ◽  
Hydride Powder

Sustained Load Cracking of Titanium Alloy Weldments

2005 ◽  
Author(s):  
Tasos Kostrivas ◽  
Lee Smith ◽  
Mike Gittos
Keyword(s):  
Stress Intensity Factor ◽  
Titanium Alloy ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Postweld Heat Treatment ◽  
Alloy Sheet ◽  
Test Method ◽  
Sustained Load ◽  
Low Oxygen ◽  
Delayed Cracking

Failure of critical titanium parts, including some offshore components, has drawn attention to delayed cracking in Ti-6Al-4V alloys, but, given good design and alloy variant selection, such failures are avoidable. Delayed cracking, or sustained load cracking (SLC), can occur at low to moderate temperature (approximately: −50 to 200°C), depending on the titanium alloy and condition. Appropriate testing methods are required to generate stress intensity threshold values (KISLC) that can be incorporated into the design of titanium structures and recommendations are needed on the optimum chemistry and microstructure for greatest resistance. In the present work threshold stress intensity factor data (KISLC) were generated for Ti-6Al-4V alloy sheet, forgings, pipe and weldments using two different rising stress intensity factor test methods. It is concluded that material with a beta-annealed microstructure and low oxygen content (i.e. extra-low interstitial material such as ASTM Grades 23 and 29), has high resistance to SLC and that weld metal and transformed heat-affected zone also perform well, before and after postweld heat treatment, provided interstitial element pick-up during welding is prevented. Purchasing material in a general ‘mill annealed’ condition is not recommended without specifying acceptable microstructures. Further refinement of test method is also recommended for defining KISLC.

scholarly journals Quantifying the effect of oxygen on micro-mechanical properties of a near-alpha titanium alloy

2021 ◽  
Author(s):  
H. M. Gardner ◽  
P. Gopon ◽  
C. M. Magazzeni ◽  
A. Radecka ◽  
K. Fox ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Electron Backscatter Diffraction ◽  
Atom Probe ◽  
Solid Solution Hardening ◽  
Low Oxygen ◽  
Order Of Magnitude ◽  
Oxygen Ingress ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

AbstractTitanium alloys are widely used in the aerospace industry, yet oxygen ingress can severely degrade the mechanical properties of titanium alloy components. Atom probe tomography (APT), electron probe microanalysis (EPMA) and nanoindentation were used to characterise the oxygen-rich layer on an in-service jet engine compressor disc, manufactured from the titanium alloy TIMETAL 834. Oxygen ingress was quantified and related to changes in mechanical properties through nanoindentation studies. The relationship between oxygen concentration, microstructure, crystal orientation and hardness has been explored through correlative hardness mapping, EPMA and electron backscatter diffraction (EBSD). It has been found that the hardening effects of microstructure and crystallography are only significant at very low-oxygen concentrations, whereas interstitial solid solution hardening dominates by order of magnitude for higher oxygen concentrations. The role of microstructure on oxygen ingress has been studied and oxygen ingress along a potential α/β interface was directly observed on the nanoscale using APT.

Titanium and Titanium Alloy via Sintering of TiH2

2010 ◽  
Vol 436 ◽  
pp. 157-163 ◽  
Author(s):  
Hong Tao Wang ◽  
Michael Lefler ◽  
Z. Zak Fang ◽  
Ting Lei ◽  
Shu Ming Fang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Alloy Powder ◽  
Low Cost ◽  
Pure Titanium ◽  
Particle Sizes ◽  
New Approach ◽  
Blended Elemental ◽  
Titanium Hydride Powder ◽  
Transus Temperature ◽  
Hydride Powder

Blended elemental (BE) powder metallurgy (PM) is a promising low cost approach for manufacture titanium and titanium alloy components. Conventional BE method relies on sintering of pure titanium metal powder, while the new approach examined in this investigation produces bulk titanium materials by sintering titanium hydride powder. Dehydrogenation and densification of TiH2 powders with different particle sizes and TiH2-6Al-4V alloy powder was studied using thermogravimetric and dilatometric techniques. The results show that the dehydrogenation of TiH2 leads to very rapid shrinkage of α-Ti during sintering. In contrast, densification TiH2-6Al-4V requires dissolution of alloy elements which occurs during sintering above its beta transus temperature.

Brazing of CP-Titanium / CP-Titanium and Titanium Alloy / Stainless Steel with Laminated Ti-Based Filler Metal

2007 ◽  
Vol 539-543 ◽  
pp. 4031-4035 ◽  
Author(s):  
Y. Miyazawa ◽  
C.S. Chang ◽  
H. Sato ◽  
Jun Suda ◽  
T. Hiraoka ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Stainless Steel ◽  
Titanium Alloy ◽  
Base Metal ◽  
Filler Metal ◽  
Eutectoid Reaction ◽  
Chemical Compositions ◽  
Low Oxygen ◽  
Continuous Type ◽  
Cp Ti

Joining technology of CP-Titanium and Titanium alloy is very important for manufacturing field. In that case of titanium brazing, chemical compositions of brazing filler metal and brazing atmosphere are very important. In this study, CP-Ti/CP-Ti and Ti alloy/Stainless Steel were brazed with Ti-based laminated brazing filler metal by using continuous type furnace under Ar gas atmosphere containing extremely low oxygen. Laminated filler was fabricated by roll bonding technology. Chemical compositions of laminated filler metal used in this study were Ti-15Cu-15Ni and Ti-20Zr-20Cu-20Ni. Brazing temperature employed in this study was 850, 900, 950, and 1000 C. These brazing temperatures were based on thermal analysis results and alpha-beta transformation temperature of the base metal used in this study. Firstly melting properties of laminated brazing filler metal was investigated with DTA and DSC. Secondary joint characteristics were estimated by micro-structural observation at the joint and mechanical properties measurement. Sound joint was obtained in this study according to outside appearance of the specimen. Ti-20Zr-20Cu-20Ni filler had low melting point as compared with Ti-15Cu-15Ni according to thermal analysis results and fillet form-ability. Ni and Cu were diffused from molten brazing filler to base metal during brazing and Ti-Cu-Ni eutectoid reaction was took placed at the based metal during cooling after brazing.

Ti6Al4V alloy fabricated by gelcasting based on low-oxygen gel system using hydride-dehydride titanium alloy powders

2021 ◽  
Author(s):  
Yanru Shao ◽  
Fang Yang ◽  
Cunguang Chen ◽  
Yang Zhou ◽  
Xinbo He ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Ti6al4v Alloy ◽  
Low Oxygen ◽  
Gel System

HIF1-α-Mediated Gene Expression Induced by Vitamin B1 Deficiency

2013 ◽  
Vol 83 (3) ◽  
pp. 188-197 ◽  
Author(s):  
Rebecca L. Sweet ◽  
Jason A. Zastre
Keyword(s):  
Gene Expression ◽  
Thiamine Deficiency ◽  
Glucose Transporter ◽  
Neuroblastoma Cell ◽  
Hypoxia Inducible Factor ◽  
Clinical Manifestations ◽  
Vitamin B1 ◽  
Low Oxygen ◽  
Glucose Transporter 1 ◽  
Metabolic Intermediates

It is well established that thiamine deficiency results in an excess of metabolic intermediates such as lactate and pyruvate, which is likely due to insufficient levels of cofactor for the function of thiamine-dependent enzymes. When in excess, both pyruvate and lactate can increase the stabilization of the hypoxia-inducible factor 1-alpha (HIF-1α) transcription factor, resulting in the trans-activation of HIF-1α regulated genes independent of low oxygen, termed pseudo-hypoxia. Therefore, the resulting dysfunction in cellular metabolism and accumulation of pyruvate and lactate during thiamine deficiency may facilitate a pseudo-hypoxic state. In order to investigate the possibility of a transcriptional relationship between hypoxia and thiamine deficiency, we measured alterations in metabolic intermediates, HIF-1α stabilization, and gene expression. We found an increase in intracellular pyruvate and extracellular lactate levels after thiamine deficiency exposure to the neuroblastoma cell line SK-N-BE. Similar to cells exposed to hypoxia, there was a corresponding increase in HIF-1α stabilization and activation of target gene expression during thiamine deficiency, including glucose transporter-1 (GLUT1), vascular endothelial growth factor (VEGF), and aldolase A. Both hypoxia and thiamine deficiency exposure resulted in an increase in the expression of the thiamine transporter SLC19A3. These results indicate thiamine deficiency induces HIF-1α-mediated gene expression similar to that observed in hypoxic stress, and may provide evidence for a central transcriptional response associated with the clinical manifestations of thiamine deficiency.

Sign in / Sign up

Export Citation Format

Share Document