Characterization of the Interface Between α and β Titanium Alloys in the Diffusion Couple

AbstractThe aim of the research was to investigate the microstructural changes caused by diffusion through interface between α and β titanium solid solutions. For this purpose, a diffusion couple composed of two single-phase titanium alloys—α type commercially pure (CP) titanium Grade 2 and near-β Ti-15V-3Al-3Cr-3Sn—was made by annealing at a temperature of 850 °C in an inert atmosphere. The performed heat treatment caused partial diffusion bonding (DB) where the α/β-interface was clearly visible. Based on the results of microscopic (light microscope (LM), scanning electron microscope/electron backscatter diffraction (SEM/EBSD), and transmission electron microscope (TEM)) examination, a significant microstructure evolution of near-β alloy in the region near the interface (diffusion-affected zone) was revealed. It was found that needlelike phases were formed both in α and β solid solutions. Moreover, in the near-β titanium alloy, pores aligned in the Frenkel plane were found. The latter finding indicated that the diffusion of alloying elements of near-β alloy is the most probable reason for the observed microstructural changes. Additionally, the “grooving” phenomenon at the α/β interface was found and it was correlated with faster diffusion through grain boundaries, rather than volume diffusion. Finally, the pore size was measured and numerically modeled. The calculated values were in good agreement with the experimental ones.

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Reduced Unit Cell Determination From Unindexed EBSD Patterns

Microscopy and Microanalysis ◽

10.1017/s1431927600037223 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 946-947 ◽

Cited By ~ 1

Author(s):

J. R. Michael ◽

R. P. Goehner

Keyword(s):

Electron Microscope ◽

Electron Backscatter Diffraction ◽

Unit Cell ◽

Phase Identification ◽

High Quality ◽

Charge Coupled Device ◽

Transmission Electron ◽

Single Pattern ◽

Backscatter Diffraction

Electron backscatter diffraction (EBSD) is a technique that can provide identification of unknown crystalline phases while exploiting the excellent imaging capabilities of the scanning electron microscope (SEM). Phase identification using EBSD has now progressed to the point that it is commercially available. Phase identification in the SEM requires high quality EBSD patterns that can only be collected using either film or charge coupled device (CCD)-based cameras. High quality EBSD patterns obtained in this manner show many diffraction features that are useful in the determination of the unit cell of the sample.’ This paper will discuss the features in the EBSD patterns and the procedure used to determine the reduced unit cell of the sample.One of the major advantages of EBSD over electron diffraction in the transmission electron microscope is the remarkable field of view that is routinely attained. The large angular view of the diffraction pattern permits many zone axes and their associated symmetries to be viewed in a single pattern or at most a few patterns.

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Cryogenic Deformation Behavior and Microstructural Characteristics of 2195 Alloy

Metals ◽

10.3390/met11091406 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1406

Author(s):

Jin Zhang ◽

Wenfu Tan ◽

Cheng Wang ◽

Chunnan Zhu ◽

Youping Yi

Keyword(s):

Electron Microscope ◽

Electron Backscatter Diffraction ◽

Underlying Mechanism ◽

Optical Microscope ◽

W State ◽

Grain Structure ◽

Cryogenic Deformation ◽

Transmission Electron ◽

Strength And Plasticity ◽

Backscatter Diffraction

Cryogenic deformation can improve the strength and plasticity of Al–Li alloy, although the underlying mechanism is still not yet well understood. The effects of cryogenic temperature on the tensile properties and microstructure of an Al–Cu–Li alloy were investigated by means of tensile property test, roughness measurement, scanning electron microscope (SEM), optical microscope (OM), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM). The results indicated that the strength and elongation of the as-annealed (O-state) and solution-treated (W-state) alloys increased with the decrease in deformation temperature, where the increasing trend of elongation of the W-state alloy was more significant than that of the O-state alloy. In addition, a temperature range was observed at approximately 178 K that caused the strength of the W-state alloy to slightly decrease. The decrease in temperature inhibited the dynamic recovery of the Al–Cu–Li alloy, which increased the dislocation density and the degree of work hardening, thus improving the strength of the alloy. At cryogenic temperatures, the internal grain structure was more involved in the deformation and the overall deformation was more uniform, which caused the alloy to have higher plasticity. This study provides a theoretical basis for the cryogenic forming of Al–Li alloy.

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Characterization of Precipitates in 3xxx Series Alloys with Zirconium

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.231.81 ◽

2015 ◽

Vol 231 ◽

pp. 81-85

Author(s):

Mariusz Bigaj ◽

Sonia Boczkal ◽

Monika Mitka ◽

Zbigniew Zamkotowicz ◽

Janusz Żelechowski ◽

...

Keyword(s):

Electron Microscope ◽

Electron Backscatter Diffraction ◽

Scanning Transmission Electron Microscope ◽

Phase Identification ◽

Transmission Electron ◽

Scanning Transmission ◽

Backscatter Diffraction ◽

Ebsd Method ◽

Eds Microanalysis

The study presents the results of microstructure examinations and phase identification of precipitates in AlMn alloys containing zirconium after heat treatment and rolling. Chemical composition in microareas was determined by Energy Dispersive Spectrometry (EDS) microanalysis performed in Scanning Electron Microscope (SEM-EDS) and Scanning Transmission Electron Microscope (STEM-EDS) modes. Phase identification was carried out using Electron Backscatter Diffraction (EBSD) method. Studies have shown that Al6Mn and α- Al17(Fe3.2Mn0.8)Si2 phases were formed in the melt. Microstructure examined by TEM showed the presence of finely dispersed spherical precipitates of zirconium. In the alloy with an addition of silicon and magnesium, numerous precipitates of an Mg2Si phase were also found.

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Crystallographic Mapping in Scanning and Transmission Electron Micrsocopy with Application to Semiconductor Materials

MRS Proceedings ◽

10.1557/proc-523-253 ◽

1998 ◽

Vol 523 ◽

Author(s):

D. J. Dingley ◽

S. I. Wright ◽

D. J. Dingley

Keyword(s):

Electron Microscope ◽

Electron Backscatter Diffraction ◽

Orientation Imaging Microscopy ◽

Lattice Parameter ◽

Dark Field ◽

Polycrystalline Materials ◽

Orientation Imaging ◽

Transmission Electron ◽

Dark Field Microscopy ◽

Backscatter Diffraction

AbstractThe two sister techniques, Electron Backscatter Diffraction and Orientation Imaging Microscopy which operate in a scanning electron microscope, are well established tools for the characterization of polycrystalline materials. Experiment has shown that the limiting resolution for mapping is the order of 0.1 microns. The basic techniques have been extended to include multiphase mapping. Whereas it has been possible to distinguish between phases of different crystal systems easily, it has not been possible to distinguish between phases that differ in lattice parameter by less than 5 %.An equivalent transmission electron microscope procedure has been developed. The technique couples standard hollow cone microscopy procedures with dark field microscopy. All possible dark field images that can be produced by tilting the electron beam are scanned to detect under what settings each crystal is brought into a diffracting condition. Subsequent analysis permits determination of both crystal phase and orientation.

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TEM Sample Preparation and FIB-Induced Damage

MRS Bulletin ◽

10.1557/mrs2007.63 ◽

2007 ◽

Vol 32 (5) ◽

pp. 400-407 ◽

Cited By ~ 484

Author(s):

Joachim Mayer ◽

Lucille A. Giannuzzi ◽

Takeo Kamino ◽

Joseph Michael

Keyword(s):

Electron Microscope ◽

Focused Ion Beam ◽

Electron Backscatter Diffraction ◽

Ion Beam ◽

X Ray ◽

Transmission Electron ◽

Electron Backscatter ◽

Future Potential ◽

Backscatter Diffraction ◽

Composite Samples

AbstractOne of the most important applications of a focused ion beam (FIB) workstation is preparing samples for transmission electron microscope (TEM) investigation. Samples must be uniformly thin to enable the analyzing beam of electrons to penetrate. The FIB enables not only the preparation of large, uniformly thick, sitespecific samples, but also the fabrication of lamellae used for TEM samples from composite samples consisting of inorganic and organic materials with very different properties. This article gives an overview of the variety of techniques that have been developed to prepare the final TEM specimen. The strengths of these methods as well as the problems, such as FIB-induced damage and Ga contamination, are illustrated with examples. Most recently, FIB-thinned lamellae were used to improve the spatial resolution of electron backscatter diffraction and energy-dispersive x-ray mapping. Examples are presented to illustrate the capabilities, difficulties, and future potential of FIB.

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Experimental Investigation of the Blanked Surface of C5191 Phosphor Bronze Sheet over a Wide Range of Blanking Speeds

Materials ◽

10.3390/ma13153335 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3335 ◽

Cited By ~ 1

Author(s):

Lei Wang ◽

Daochun Hu ◽

Minghe Chen ◽

Hongjun Wang

Keyword(s):

Electron Microscope ◽

High Speed ◽

Electron Backscatter Diffraction ◽

Local Area ◽

Selected Area Electron Diffraction ◽

Transmission Electron ◽

Low Dislocation Density ◽

Wide Range ◽

Backscatter Diffraction

The influence of blanking speed on the blanked surface quality of C5191 bronze phosphorus sheets, with a thickness of 0.12 mm, was systematically studied to demonstrate the mechanism under high speed blanking. The morphology and microstructure of the blanked edge were observed by using a variety of techniques, including optical microscopy (OM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM). The results revealed that the local temperature and microhardness of the shear zone increased with the increase in blanking speed. Moreover, the quality of blanked edge significantly improved with the increase in blanking speed due to the combined influence of strain rate hardening and thermal softening. In addition, the blanked edge grains were elongated along the blanking direction and formed dislocation cells and sub-grains in some areas. The blanked edge is dominated by {000} <100> cubic texture at higher blanking speeds, and {112} <111> texture at lower blanking speeds. When punched at an ultra-high speed of 3000 strokes per minute (SPM 3000), the local area of the blanked edge exhibited distinct microstructural features, including low dislocation density, nanocrystals with high-angle grain boundaries, and significant differences in grain orientation. Additionally, the selected area electron diffraction (SAED) pattern exhibited a discontinuous ring-like structure, indicating the occurrence of adiabatic shearing with dynamic recrystallization.

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On the reliability of fully automatic indexing of electron diffraction patterns obtained in a transmission electron microscope

Journal of Applied Crystallography ◽

10.1107/s0021889805032966 ◽

2006 ◽

Vol 39 (1) ◽

pp. 101-103 ◽

Cited By ~ 12

Author(s):

A. Morawiec ◽

E. Bouzy

Keyword(s):

Electron Microscope ◽

Electron Diffraction ◽

Transmission Electron Microscope ◽

Current Practice ◽

Electron Backscatter Diffraction ◽

Automatic Indexing ◽

Transmission Electron ◽

Fully Automatic ◽

Diffraction Patterns ◽

Backscatter Diffraction

Orientation maps similar to electron backscatter diffraction maps can be obtained in a transmission electron microscope. A method of such mapping by automatic indexing of electron diffraction patterns has been proposed recently. The procedure is relatively simple and fast but it does not avoid the 180° ambiguity. Using tests on simulated patterns, it is shown that under current practice automatic indexing may give a considerable fraction of erroneous solutions. Optimization of measurement conditions leading to a reduction of that fraction is considered.

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Microstructure Characterization of Large Strain Deformed Fe-32%Ni Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.146-147.248 ◽

2010 ◽

Vol 146-147 ◽

pp. 248-251

Author(s):

Bai Xiong Liu ◽

Bao Jun Han

Keyword(s):

Electron Microscope ◽

Grain Boundaries ◽

Electron Backscatter Diffraction ◽

Large Strain ◽

Internal Stresses ◽

Transmission Electron ◽

Resolution Electron ◽

Ni Alloy ◽

Backscatter Diffraction

High-resolution electron backscatter diffraction (EBSD) in scanning electron microscope and transmission electron microscope (TEM) were used to investigate the microstructure of Fe-32%Ni alloy processed by large strain multi-axial forging. The samples were compressed with loading direction changed through 90º from pass to pass at temperature of 500°C and a strain rate of 10-2/s. The results show the microstructure evolution is characterized by full development of almost equi-axed fine grains, not well-developed grain boundaries accompanied by high dislocation density and the existence of extensive extinction contours in the vicinity of grain boundaries, and the structure characteristics indicate that the grain boundaries are in a non-equilibrium state with high internal stresses.

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Phenomena Associated with Oxygen in Titanium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061562 ◽

1967 ◽

Vol 25 ◽

pp. 310-311

Author(s):

E. U. Lee ◽

P. A. Garner ◽

J. S. Owens

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Microscope ◽

Microstructural Changes ◽

Electrolytic Polishing ◽

Interstitial Impurities ◽

Thin Foils ◽

Transmission Electron ◽

Iodide Titanium ◽

Alpha Titanium

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.

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Oxygen Induced Phase Transformation in TC21 Alloy with a Lamellar Microstructure

Metals ◽

10.3390/met11010163 ◽

2021 ◽

Vol 11 (1) ◽

pp. 163

Author(s):

Shu Wang ◽

Yilong Liang ◽

Hao Sun ◽

Xin Feng ◽

Chaowen Huang

Keyword(s):

Electron Microscopy ◽

Phase Transformation ◽

Oxygen Uptake ◽

Titanium Alloys ◽

Electron Backscatter Diffraction ◽

Lamellar Microstructure ◽

Α Phase ◽

Transmission Electron ◽

The Matrix ◽

Oxygen Ingress

The main objective of the present study was to understand the oxygen ingress in titanium alloys at high temperatures. Investigations reveal that the oxygen diffusion layer (ODL) caused by oxygen ingress significantly affects the mechanical properties of titanium alloys. In the present study, the high-temperature oxygen ingress behavior of TC21 alloy with a lamellar microstructure was investigated. Microstructural characterizations were analyzed through optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). Obtained results demonstrate that oxygen-induced phase transformation not only enhances the precipitation of secondary α-phase (αs) and forms more primary α phase (αp), but also promotes the recrystallization of the ODL. It was found that as the temperature of oxygen uptake increases, the thickness of the ODL initially increases and then decreases. The maximum depth of the ODL was obtained for the oxygen uptake temperature of 960 °C. In addition, a gradient microstructure (αp + β + βtrans)/(αp + βtrans)/(αp + β) was observed in the experiment. Meanwhile, it was also found that the hardness and dislocation density in the ODL is higher than that that of the matrix.

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