Microstructural characterization of as-sintered titanium and titanium alloys

2015 ◽  
pp. 555-578 ◽  
Author(s):  
Ming Yan
Keyword(s):  
Titanium Alloys ◽  
Microstructural Characterization ◽  
Sintered Titanium

Mechanical and Microstructural Characterization of the Ti-25Ta-25Nb Alloy for Dental Applications

2016 ◽  
Vol 869 ◽  
pp. 935-939 ◽  
Author(s):  
M.R. Seixas ◽  
C. Bortolini Jr. ◽  
R.T. Konatu ◽  
A. Pereira Jr. ◽  
Ana Paula Rosifini Alves Claro
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloys ◽  
Biomedical Applications ◽  
Cold Work ◽  
Microstructural Characterization ◽  
Nickel Titanium ◽  
Low Elastic Modulus ◽  
Nickel Titanium Alloys ◽  
Dental Applications

Titanium and its alloys have been used in biomedical applications due to their excellent properties such as high corrosion resistance, biocompatibility and mechanical properties. In orthodontics, initially, it was common to use nickel-titanium alloys, however due to allergic reactions of patients, new titanium alloys containing elements such as niobium and tantalum are being studied. The Ti-25Ta-25Nb alloy is a β-titanium alloy and it has a low elastic modulus. In the present work, the ternary alloy was evaluated after cold work by swaging followed by solubilization treatment. Microstructure and mechanical properties were evaluated after each step of the process. Results were similar to find in the literature for this alloy obtained by other processing rote.

Characterization of Ti-35Nb-7Zr-5Ta Alloy Produced by Powder Metallurgy

2005 ◽  
Vol 498-499 ◽  
pp. 34-39 ◽  
Author(s):  
Elisa B. Taddei ◽  
Vinicius André Rodrigues Henriques ◽  
Cosme Roberto Moreira Silva ◽  
Carlos Alberto Alves Cairo
Keyword(s):  
Powder Metallurgy ◽  
Titanium Alloys ◽  
Microstructural Characterization ◽  
Cold Isostatic Pressing ◽  
Microstructural Development ◽  
Potential Toxic Elements ◽  
Metallic Biomaterials ◽  
Low Modulus ◽  
Orthopedic Applications

Abstract: Titanium and titanium alloys present the highest biocompatibility among metallic biomaterials. The ideal titanium alloy for orthopedic applications should have low modulus of elasticity (near the bone), excellent mechanical strength, high corrosion resistance, formability and no potential toxic elements. Among titanium alloys, the Ti-35Nb-7Zr-5Ta alloy, due its high biocompatibility and lower Young’s modulus is a promising candidate for implants material. The titanium alloys production by powder metallurgy, starting from the elementary powders, is a viable route due at the smaller costs and larger operational facilities. The Ti-35Nb-7Zr-5Ta samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering between 900 at 1700 °C, in vacuum, under a heating rate of 20 °C×min-1 for 1h. The objective of this work is the analysis of alloy microstructural evolution from the powders dissolution under the increase of the sintering temperature. For the alloy microstructural characterization, scanning electron microscopy and Vickers microhardness measurements, were used. Density was measured by Archimedes method. The samples presented high densification, an homogeneous microstructural development, with complete dissolution of alloying elements in the titanium matrix with the temperature increase.

scholarly journals Microstructural Characterization of Several Coatings Deposited on Tialnb Intermetallic Alloy/ Charakterystyka Mikrostruktury Wybranych Warstw Wytworzonych Na Podłożu >Stopu Tytanu Na Osnowie Fazy Międzymetalicznej Tialnb

2014 ◽  
Vol 59 (4) ◽  
pp. 1547-1551 ◽  
Author(s):  
M. Góral ◽  
M. Pytel ◽  
K. Dychton
Keyword(s):  
Titanium Alloys ◽  
Tial Alloy ◽  
Intermetallic Phase ◽  
Microstructural Characterization ◽  
Intermetallic Alloy ◽  
Pack Cementation ◽  
High Porosity ◽  
Aluminide Coatings ◽  
New Type

Abstract Titanium alloys based on the γ -TiAl intermetallic phase are a type of material which may replace nickel supperalloys in high temperature applications. Not enough resistance to corrosion at temperatures above 900°C remains the biggest limitation in industrial practices. The paper presents results of preliminary research into application of new type heat resistant coatings on the basis of γ -TiAl alloy. MeCrAlY and Si coatings were formed by pack cementation method. Aluminide coatings were deposited by pack cementation method and VPA. Research results have shown that except for the coating formed by VPA, coatings were characterized by high porosity and therefore would not ensure appropriate protection against oxidation. Further research will be necessary into application of the VPA method in protecting γ-TiAl titanium alloys in order to improve their heat resistance.

scholarly journals Microstructural Characterization Of Quenched And Plastically Deformed Two-Phase α+β Titanium Alloys

2015 ◽  
Vol 60 (3) ◽  
pp. 2033-2038 ◽  
Author(s):  
M. Motyka ◽  
J. Sieniawski ◽  
W. Ziaja ◽  
G. Mrówka-Nowotnik
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Titanium Alloys ◽  
Thermomechanical Processing ◽  
Microstructural Characterization ◽  
Two Phase ◽  
Deformation Degree ◽  
Plastic Deformation Process ◽  
Deformation Processes

Abstract Development of microstructure in two-phase α+β titanium alloys is realized by thermomechanical processing – sequence of heat treatment and plastic working operations. Analysis of achieved results indicates that hot plastic deformation – depending on deformation degree – causes significant elongation of α phase grains. Following heat treatment and plastic deformation processes lead to their fragmentation and spheroidization. Characterization of microstructure morphology changes during thermomechanical processing of quenched Ti-6Al-4V and Ti-6Al-2Mo-2Cr alloys is presented in the paper. The effect of martensitic phase α’(α”) on microstructure development in plastic deformation process was confirmed.

scholarly journals Microstructural Characterization of Dissimilar Titanium Alloys Joints Using Ni/Al Nanolayers

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 715 ◽  
Author(s):  
Sónia Simões ◽  
Filomena Viana ◽  
Ana Ramos ◽  
M. Vieira ◽  
Manuel Vieira
Keyword(s):  
Titanium Alloys ◽  
Diffusion Bonding ◽  
Base Material ◽  
Microstructural Characterization ◽  
Thin Layers ◽  
Electron Microscopies ◽  
Base Materials ◽  
Material Surfaces ◽  
Scanning Electron

This study demonstrates the potential of the use of Ni/Al nanolayers for joining dissimilar titanium alloys. For this purpose, a detailed microstructural characterization of the diffusion bonding interfaces of TiAl to Ti6Al4V, TiAl to TiNi and TiNi to Ti6Al4V was carried out. The nanolayers (alternated aluminum and nickel (Ni-7V wt.%) layers) were deposited onto the base material surfaces. Diffusion bonding was performed at 700 and 800 °C under pressures ranging from 5 to 40 MPa and at dwell times between 60 and 180 min. Microstructural characterization was performed using high resolution transmission and scanning electron microscopies. The results revealed that dissimilar titanium joints (TiAl to Ti6Al4V, TiAl to TiNi and TiNi to Ti6Al4V) assisted by Ni/Al nanolayers can be obtained successfully at 800 °C for 60 min using a pressure of 20 MPa. The bond interfaces are thin (less than 10 µm) and mainly composed of NiAl grains with a few nanometric grains of Al8V5. Thin layers of Al-Ni-Ti intermetallic compounds were formed adjacent to the base materials due to their reaction with the nanolayers.

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

1987 ◽  
Vol 45 ◽  
pp. 326-327
Author(s):  
A.K. Rai ◽  
A.K. Petford-Long ◽  
A. Ezis ◽  
D.W. Langer
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Almost Everywhere ◽  
Spacer Layer ◽  
Good Contact ◽  
The Relationship ◽  
Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

Microstructural characterization of a cast RENi5-based alloy

1993 ◽  
Vol 51 ◽  
pp. 1176-1177
Author(s):  
G. M. Micha ◽  
L. Zhang
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Microstructural Characterization ◽  
Binary Compound ◽  
Nickel Metal ◽  
Cast Material ◽  
Nickel Metal Hydride ◽  
Transmission Electron ◽  
Cast Condition

RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.

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