scholarly journals Quantitative Strengthening Evaluation of Powder Metallurgy Titanium Alloys with Substitutional Zr and Interstitial O Solutes via Homogenization Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6561
Author(s):  
Katsuyoshi Kondoh ◽  
Shota Kariya ◽  
Anak Khantachawana ◽  
Abdulaziz Alhazaa ◽  
Junko Umeda
Keyword(s):  
Uniform Distribution ◽  
Yield Stress ◽  
Electron Backscatter Diffraction ◽  
Process Conditions ◽  
The Matrix ◽  
Calculation Results ◽  
Decomposition Behavior ◽  
Ti Powder ◽  
Backscatter Diffraction

The decomposition behavior of ZrO2 particles and uniform distribution of Zr and O solutes were investigated by employing in situ scanning electron microscope-electron backscatter diffraction (SEM-EBSD) analysis and thermogravimetric-differential thermal analysis (TG-DTA) to optimize the process conditions in preparing Ti-Zr-O alloys from the pre-mixed pure Ti powder and ZrO2 particles. The extruded Ti-Zr-O alloys via homogenization and water-quenching treatment were found to have a uniform distribution of Zr and O solutes in the matrix and also showed a remarkable improvement in the mechanical properties, for example, the yield stress of Ti-3 wt.% ZrO2 sample (1144.5 MPa) is about 2.5 times more than the amount of yield stress of pure Ti (471.4 MPa). Furthermore, the oxygen solid-solution was dominant in the yield stress increment, and the experimental data agreed well with the calculation results estimated using the Hall–Petch equation and Labusch model.

Grain Growth in Al: First Results from a Combined Study of Bulk and In-Situ Experiments Using a Columnar Structured Al Foil

2004 ◽  
Vol 467-470 ◽  
pp. 935-940 ◽  
Author(s):  
Sandra Piazolo ◽  
Vera G. Sursaeva ◽  
David J. Prior
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Boundary Energy ◽  
Complete Replacement ◽  
Von Neumann ◽  
In Situ Experiments ◽  
First Results ◽  
Backscatter Diffraction

First results from grain growth experiments in a columnar structured Al foil show several interesting features: (a) the grain size distribution remains heterogeneous even after up to 300 min. annealing and (b) the Von Neumann-Mullins relation is not always satisfied. To clarify the underlying reasons for these features, in-situ heating experiments within a Scanning Electron Microscope (SEM) were combined with detailed Electron Backscatter Diffraction (EBSD) analysis. These show that the movement of boundaries can be strongly heterogeneous. For example, the complete replacement of one grain by a neighbouring grain without significant change of the surrounding grain boundary topology is frequently seen. Experiments show that grain boundary energy and/or mobility are anisotropic both with respect to misorientation and orientation of grain boundary plane. Low energy and/or mobility boundaries are commonly low angle boundaries, twin boundaries and boundaries that form traces to a low index plane of at least one of the adjacent grains. As a consequence the Von Neumann-Mullins relation is not always satisfied.

In Situ Produced MMC Layer by Laser Melt Injection

2010 ◽  
Vol 649 ◽  
pp. 61-66
Author(s):  
Zoltán Kálazi ◽  
Viktória Janó ◽  
Gábor Buza
Keyword(s):  
Carbon Content ◽  
Composite Layer ◽  
Pure Titanium ◽  
Base Material ◽  
Titanium Content ◽  
Steel Sample ◽  
Low Carbon ◽  
The Matrix ◽  
Ti Powder

Tungsten (W) based alloy composite layer reinforced with TiC particles has been successfully prepared on unalloyed steel sample by LMI technology. In order to obtain in situ produced TiC reinforcement, pure titanium has been introduced to the melt pool. WC powder was added for increasing the carbon content of the layer in order to avoid the softening of the matrix (with low carbon content) during TiC formation. The present study aims to investigate the optimum amount of injected WC and Ti powder to improve wear resistance and hardness of the layer. Samples were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The maximum hardness of the layer has been reached ~900HV in case of 2-4wt% of titanium content. Ti has been collected all of the carbon from the matrix when titanium content was 9,6wt%, which resulted that the austenite and (Fe,W)6C phases have been disappeared. Only α-Fe and TiC phases were presented in the layer. The hardness of the layer reduced to the hardness of the base material.

scholarly journals Characterization of Coarse-Grained Heat-Affected Zones in Al and Ti-Deoxidized Offshore Steels

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1096
Author(s):  
Henri Tervo ◽  
Antti Kaijalainen ◽  
Vahid Javaheri ◽  
Satish Kolli ◽  
Tuomas Alatarvas ◽  
...  
Keyword(s):  
Prior Austenite ◽  
Electron Backscatter Diffraction ◽  
Coarse Grained ◽  
Grain Coarsening ◽  
Austenite Grain ◽  
The Matrix ◽  
Backscatter Diffraction ◽  
Prior Austenite Grain ◽  
Deoxidation Practice

Deterioration of the toughness in heat-affected zones (HAZs) due to the thermal cycles caused by welding is a known problem in offshore steels. Acicular ferrite (AF) in the HAZ is generally considered beneficial regarding the toughness. Three experimental steels were studied in order to find optimal conditions for the AF formation in the coarse-grained heat-affected zone (CGHAZ). One of the steels was Al-deoxidized, while the other two were Ti-deoxidized. The main focus was to distinguish whether the deoxidation practice affected the AF formation in the simulated CGHAZ. First, two different peak temperatures and prolonged annealing were used to study the prior austenite grain coarsening. Then, the effect of welding heat input was studied by applying three cooling times from 800 °C to 500 °C in a Gleeble thermomechanical simulator. The materials were characterized using electron microscopy, energy-dispersive X-ray spectrometry, and electron backscatter diffraction. The Mn depletion along the matrix-particle interface was modelled and measured. It was found that AF formed in the simulated CGHAZ of one of the Ti-deoxidized steels and its fraction increased with increasing cooling time. In this steel, the inclusions consisted mainly of small (1–4 μm) TiOx-MnS, and the tendency for prior austenite grain coarsening was the highest.

scholarly journals Novel −75°C SEM cooling stage: application for martensitic transformation in steel

Microscopy ◽  
2020 ◽  
Author(s):  
Kaneaki Tsuzazki ◽  
Motomichi Koyama ◽  
Ryosuke Sasaki ◽  
Keiichiro Nakafuji ◽  
Kazushi Oie ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Electron Backscatter Diffraction ◽  
Dislocation Slip ◽  
In Situ Observation ◽  
Contrast Imaging ◽  
Cooling Stage ◽  
Electron Channelling ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Abstract Microstructural changes during the martensitic transformation from face-centred cubic (FCC) to body-centred cubic (BCC) in an Fe-31Ni alloy were observed by scanning electron microscopy (SEM) with a newly developed Peltier stage available at temperatures to  −75°C. Electron channelling contrast imaging (ECCI) was utilized for the in situ observation during cooling. Electron backscatter diffraction analysis at ambient temperature (20°C) after the transformation was performed for the crystallographic characterization. A uniform dislocation slip in the FCC matrix associated with the transformation was detected at −57°C. Gradual growth of a BCC martensite was recognized upon cooling from −57°C to −63°C.

scholarly journals The Effect of Simultaneous Si and Ti/Mo Alloying on High-Temperature Strength of Fe3Al-Based Iron Aluminides

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4268
Author(s):  
Věra Vodičková ◽  
Martin Švec ◽  
Pavel Hanus ◽  
Pavel Novák ◽  
Antonín Záděra ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Yield Stress ◽  
Electron Backscatter Diffraction ◽  
Xrd Analysis ◽  
Iron Aluminides ◽  
High Temperature Strength ◽  
X Ray Diffraction ◽  
Backscatter Diffraction

The effect of phase composition and morphology on high-temperature strength in the compression of Fe-Al-Si-based iron aluminides manufactured by casting was investigated. The structure and high-temperature strength in the compression of three alloys—Fe28Al5Si, Fe28Al5Si2Mo, and Fe28Al5Si2Ti—were studied. Long-term (at 800 °C for 100 h) annealing was performed for the achievement of structural stability. The phase composition and grain size of alloys were primarily described by means of scanning electron microscopy equipped with energy dispersive analysis and Electron Backscatter Diffraction (EBSD). The phase composition was verified by X-ray diffraction (XRD) analysis. The effect of Mo and Ti addition as well as the effect of long-term annealing on high-temperature yield stress in compression were investigated. Both additives—Mo and Ti—affected the yield stress values positively. Long-term annealing of Fe28Al5Si-X iron aluminide alloyed with Mo and Ti deteriorates yield stress values slightly due to grain coarsening.

In-situ Recrystallization Experiments Using Electron Backscatter Diffraction

2007 ◽  
Vol 13 (S02) ◽  
Author(s):  
D Prior ◽  
M Bestmann ◽  
S Piazolo ◽  
NC Seaton ◽  
DJ Tatham ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Creep Deformation Microstructures in DS Nb-Hf-Ti-Si In-Situ Composites

1999 ◽  
Vol 5 (S2) ◽  
pp. 258-259
Author(s):  
S.D. Sitzman ◽  
B.P. Bewlay
Keyword(s):  
Creep Deformation ◽  
Microprobe Analysis ◽  
Electron Backscatter Diffraction ◽  
Czochralski Method ◽  
Directionally Solidified ◽  
Creep Tests ◽  
In Situ Composites ◽  
Before And After ◽  
Backscatter Diffraction

Directionally solidified (DS) in-situ composites based on (Nb) and (Nb) silicides, such as Nb5Si3 and Nb3Si, are presently under investigation as high-temperature structural materials [1, 2]. Alloying additions of elements such as Hf, Ti and Mo to these silicides are also being explored. The present paper describes the microstructure of a DS Nb-silicide based composite before and after creep deformation.Alloys were prepared from high purity elements (>99.9%) using induction levitation melting in a segmented water-cooled copper crucible. The alloys were directionally solidified using the Czochralski method [2]. Creep tests were conducted at 1200°C to 50% deformation. Characterization was performed using scanning electron microscopy, electron microprobe analysis (EMPA), and electron backscatter diffraction pattern analysis (EBSP).

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