The Microstructure of Titanium Beryllide, Tibe12

1990 ◽  
Vol 213 ◽  
Author(s):  
D. Banerjee ◽  
L. Jacobson ◽  
J. Zindell ◽  
T.E. Mitchell
Keyword(s):  
Antiphase Domain ◽  
Weight Percent ◽  
Sputter Deposition ◽  
Inert Gas ◽  
Second Phase ◽  
Defect Structures ◽  
Arc Melting ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Domain Boundaries

ABSTRACTTitanium beryllide (TiBe12) has been processed by various techniques, including inert gas arc melting, sputter deposition and as second phase particles in atomized powder of alloys ranging in composition from 1 to 35 weight percent Ti. The TiBe12 that formed in the various alloys was characterized by transmission electron microscopy. Defect structures such as microtwinning, antiphase domain boundaries and dislocations have been observed within the beryllide phase. Descriptions of these defect structures will be presented in this paper, together with a discussion of their origin.

scholarly journals Effect of Niobium and Titanium Addition on Formation of Second Phase Particles in CHQ Steel Using Transmission Electron Microscope

2021 ◽  
Vol 40 (1) ◽  
pp. 31-37
Author(s):  
Shahid Hussain Abro
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Percent ◽  
Holding Time ◽  
Second Phase ◽  
Steel Matrix ◽  
Ehlers Danlos Syndrome ◽  
Transmission Electron ◽  
Second Phase Particles

It is common practice that formation of second phase particles such as nitrides or carbides in the steel matrix has significant role to control the grain size of steel. An attempt is made in the present research work to find out the role of nitrogen to form the nitride particles either with Al, Ti, B, Cr or Si. Two steel samples Steel-A and Steel-B with same titanium and aluminum weight percent in the chemical composition were obtained in hot rolled conditions from international market with only the difference of presence of Niobium in Steel-A. Solution heat treatment was performed at 1350°C with 60 minutes holding time in protherm heat treatment furnace available locally was used to dissolve the particles and then steel samples were reheat treated at 800°C with holding time of 60 minutes and water quenched and microstructure was revealed. Transmission electron microscope connected with Ehlers-Danlos Syndrome (EDS) was used to reveal the morphology of second phase particles. Both samples for a high resolution power Transmission Electron Microscopy (TEM) (Jeol JEM 3010) analysis were prepared by using carbon extraction replica method in 5% Nital solution as an etching technique. Both samples were then caught in copper grid of 3mm for using TEM analysis. TEM micrographs clearly revealed the second phase particles in the matrix of steel. The EDS peaks were studied and it was found that the peaks showed the titanium peaks in both the samples A and B and surprisingly there was no any peak found for aluminum. Stoichiometric calculations were carried out and it was found that weight percent nitrogen required for forming TiN is 0.0073, however the total nitrogen present in both the steels A and B is 0.0058 and 0.0061 respectively. That means that all the nitrogen present in the steel matrix was consumed by titanium to form the Titanium Nitride (TiN) so there was no nitrogen remain to fulfil the requirement of aluminum to form the Aluminum Nitride (AlN) particles.

scholarly journals Understanding the Effect of Aluminum Addition on the Forming of Second Phase Particles on Grain Growth of Micro-Alloyed Steel

2020 ◽  
Vol 10 (1) ◽  
pp. 5153-5156
Author(s):  
S. H. Abro ◽  
H. A. Moria ◽  
A. Chandio ◽  
A. Z. Al-Khazaal
Keyword(s):  
Weight Percent ◽  
Rolling Process ◽  
Second Phase ◽  
Steel Matrix ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
The Matrix ◽  
Micro Alloyed Steel

The formation of second phase particles in the steel matrix during melting and casting plays an important role in controlling the grain size of steel. An attempt is made in the present work to find the role of nitrogen on forming nitride particles either with aluminum or titanium. Two steel samples with the same titanium and aluminum weight percent in their chemical composition were collected after the hot rolling process. Solution heat treatment at 1350°C for 60min holding time was used to dissolve the particles and then the steel samples were reheated at 800°C for 60min, water quenched and their microstructure was revealed by usual grinding and polishing process using 2% Nital. A transmission electron microscope connected with EDS was used to reveal the morphology of the second phase particles. The samples for TEM analysis were prepared by the replica extraction method in 5% Nital solution. The samples were then caught in 3mm copper grid for TEM analysis. TEM micrographs revealed the second phase particles in the matrix of steel. EDS peaks were studied and titanium peaks were found in both samples and surprisingly there was not any peak found for aluminum.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Observation of antiphase domain boundaries in GaAs on silicon by transmission electron microscopy

1988 ◽  
Vol 53 (13) ◽  
pp. 1207-1209 ◽  
Author(s):  
J. B. Posthill ◽  
J. C. L. Tarn ◽  
K. Das ◽  
T. P. Humphreys ◽  
N. R. Parikh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Antiphase Domain ◽  
Transmission Electron ◽  
Domain Boundaries

Transmission electron microscopy observation of second-phase particles in β–Si3N4 grains

1999 ◽  
Vol 14 (7) ◽  
pp. 2959-2965 ◽  
Author(s):  
Naoto Hirosaki ◽  
Tomohiro Saito ◽  
Fumio Munakata ◽  
Yoshio Akimune ◽  
Yuichi Ikuhara
Keyword(s):  
Electron Microscopy ◽  
Silicon Nitride ◽  
Heat Treating ◽  
High Resolution Electron Microscopy ◽  
Second Phase ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Second Phase Particles ◽  
Coarse Grains ◽  
Sintered Silicon

Silicon nitride was fabricated by adding Y2O3 and Nd2O3 as sintering additives, sintering for 8 h at 1900 °C, and heat treating for 4 h at 2200 °C to enhance grain growth. The microstructure was investigated by scanning electron microscopy, high-resolution electron microscopy, energy dispersive x-ray spectroscopy (EDS), and electron microdiffraction. This material had a duplex microstructure composed of many fine grains and a few coarse grains. In β–Si3N4 grains, second-phase particles with the composition of liquid phase, Y–Nd–Si–O or Y–Nd–Si–O–N, in the size of 10–30 nm were observed. EDS spectra and microdiffraction patterns revealed that those were amorphous or crystalline particles of Y–Nd–apatite, (Y,Nd)10Si6O24N2. These particles were presumably formed during cooling by the precipitation of Y–Nd–Si–O–N, which was trapped in the β–Si3N4 grains as solid solution or trapped liquid. The results suggest that attention should be paid to the trace amounts of trapped elements in β–Si3N4 grains in trying to improve the thermal conductivity of sintered silicon nitride.

Effect of Second Phase Particles on the Tensile Instability of a Nanostructured Al-1%Si Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 2629-2634 ◽  
Author(s):  
Tian Lin Huang ◽  
Gui Lin Wu ◽  
Qing Liu ◽  
Xiao Xu Huang
Keyword(s):  
Tensile Tests ◽  
Structural Features ◽  
Second Phase ◽  
Commercial Purity ◽  
Localized Deformation ◽  
Dispersed Particles ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Tensile Instability ◽  
Recovery Annealing

A nanostructured Al-1%Si alloy containing dispersed Si particles was produced by heavily cold-rolling to study the effect of second phase particles on the tensile instability of nanostructured metals. Tensile tests were conducted on the as-deformed sample and the samples after recovery annealing treatments. The structural features of deformed and annealed samples were characterized by transmission electron microscopy. By comparing with the behavior of nanostructured commercial purity Al without dispersed particles, a remarked improvement in the tensile stability was found. This is related to a prevention of localized deformation by the presence of finely dispersed Si particles in the nanoscale matrix structure.

scholarly journals Unravelling the characteristics of Al-alloy corrosion at the atomic to nanometre scale by transmission electron microscopy

2020 ◽  
Vol 326 ◽  
pp. 01007
Author(s):  
Shravan K. Kairy ◽  
Nick Birbilis
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Al Alloy ◽  
Second Phase ◽  
Clear Understanding ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Al Matrix

The localised corrosion associated with Mg2Si in the Al-matrix of an Al-Mg-Si alloy was studied in 0.1 M NaCl at pH 6 by quasi in-situ transmission electron microscopy. Herein, physical imaging of corrosion at the atomic to nanometre scale was performed. Phase transformation and subsequent chemical composition variations associated with the localised corrosion of Mg2Si were studied. It was observed that corrosion initiated upon Mg2Si, often preferentially at the interface with the Al-matrix, and propagated until Mg2Si was completely dealloyed by Mg-dissolution, resulting in an amorphous SiO-rich phase remnant. The SiO-rich remnant became electrochemically inert and did not initiate corrosion in the Al-matrix. This study provides a clear understanding on the localised corrosion of Al-alloys associated with Mg2Si. In addition, the methodology followed in this study can also be applied to understand the role of precipitates and second phase particles in the localised corrosion of Al-alloy systems.

Microstructure of Nb BASED A12O3 Composites

1998 ◽  
Vol 4 (S2) ◽  
pp. 588-589
Author(s):  
C. Scheu ◽  
G. Dehm ◽  
W. D. Kaplan ◽  
D. E. Garcia ◽  
N. Claussen
Keyword(s):  
Ceramic Composites ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Powder Mixtures ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Wide Range ◽  
Metal Ceramic ◽  
High Resolution Tem ◽  
Al Powder

Metal-ceramic composites possess a wide range of applications due to an increased fracture toughness and strength compared to monolithic materials. A better understanding of the correlation between properties and microstructure of these materials requires a detailed analysis of the phases which form during processing. This can be accomplished by using various transmission electron microscopy (TEM) methods. In this study Nb based AI2O3 composites were investigated. The composites were prepared by pressureless sintering 2 of compacts of attrition milled AI2O3 and prealloyed Nb(Al) powder mixtures. The addition of 7 wt.% of Al to the Nb powder is supposed to assist in rapid and complete sintering of the material. The microstructure was studied in detail by conventional TEM using selected area diffraction (SAD). The chemistry and structure of the occurring phases, second phase particles and grain boundaries were analysed by analytical TEM and high resolution TEM (HRTEM).

Effect of Second-Phase Particles on Grain Refinement of Mg-Al-Zn Alloy during ECAE

2007 ◽  
Vol 546-549 ◽  
pp. 315-318
Author(s):  
Li Jin ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng ◽  
Da Li Mao ◽  
Wen Jiang Ding
Keyword(s):  
Electron Microscopy ◽  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Second Phase ◽  
Transmission Electron ◽  
Initial Stage ◽  
Mg17al12 Phase ◽  
Second Phase Particles ◽  
Zn Alloy ◽  
Zn Alloys

The effect of second-phase particles on the grain refinement of AZ61 and AZ91 Mg-Al-Zn alloys with different volume fractions of β-Mg17Al12 phase particles during equal channel angular extrusion (ECAE) has been investigated. The microstructure were observed by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed that grain refinement was enhanced by second phase particles at initial stage of ECAE. And finer grains with the high angle grain boundaries (HAGBs) and disperse second-phase particles could be obtained in AZ61 and AZ91 after 8 passes of ECAE.

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