Structural characterization and nanoscale strain field analysis of α/β interface layer of a near α titanium alloy

Abstract In this article, the structural and nanoscale strain field of the α/β phase interface layer in Ti80 alloy were studied by using high-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA). The α/β interface layer was observed in forged and different annealed Ti80 alloys, which is mainly composed of lamellar face-centered cubic (FCC) phase region and α′ + β region. The FCC phases between α and β phases show a twin relationship, and the twinning plane is ( 1 1 ¯ 1 ) (1\bar{1}1) . The orientation relationship of the β phase, the α phase, and the FCC phase is (110)β//(0001)α// ( 1 1 ¯ 1 ) (1\bar{1}1) FCC and [ 1 ¯ 11 \bar{1}11 ]β//[ 2 1 ¯ 1 ¯ 0 2\bar{1}\bar{1}0 ]α//[011]FCC. The nanoscale strain field of FCC + α and β + α′ regions was analyzed by using the GPA technology. The FCC + α region shows more significant strain gradient than the α′ + β region, and ε FCC > ε α, ε α′ > ε β. The influence of element addition on the formation mechanism of the FCC phase was discussed. The addition of Zr promotes the formation of the FCC phase by inducing lattice distortion and reducing the stacking fault energy of the α phase. In addition, the Al element forms an obvious concentration gradient around the interface layer during the cooling process of the alloy, which provides a driving force for the formation of the FCC phase.

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Stability and equation of state of face-centered cubic and hexagonal close packed phases of argon under pressure

Scientific Reports ◽

10.1038/s41598-021-93995-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Agnès Dewaele ◽

Angelika D. Rosa ◽

Nicolas Guignot ◽

Denis Andrault ◽

João Elias F. S. Rodrigues ◽

...

Keyword(s):

Equation Of State ◽

Single Crystal ◽

Single Crystal Sample ◽

Moderate Pressure ◽

Face Centered Cubic ◽

Experimental Conditions ◽

Crystal Sample ◽

Hexagonal Close Packed ◽

Face Centered ◽

Fcc Phase

AbstractThe compression of argon is measured between 10 K and 296 K up to 20 GPa and and up to 114 GPa at 296 K in diamond anvil cells. Three samples conditioning are used: (1) single crystal sample directly compressed between the anvils, (2) powder sample directly compressed between the anvils, (3) single crystal sample compressed in a pressure medium. A partial transformation of the face-centered cubic (fcc) phase to a hexagonal close-packed (hcp) structure is observed above 4.2–13 GPa. Hcp phase forms through stacking faults in fcc-Ar and its amount depends on pressurizing conditions and starting fcc-Ar microstructure. The quasi-hydrostatic equation of state of the fcc phase is well described by a quasi-harmonic Mie–Grüneisen–Debye formalism, with the following 0 K parameters for Rydberg-Vinet equation: $$V_0$$ V 0 = 38.0 Å$$^3$$ 3 /at, $$K_0$$ K 0 = 2.65 GPa, $$K'_0$$ K 0 ′ = 7.423. Under the current experimental conditions, non-hydrostaticity affects measured P–V points mostly at moderate pressure ($$\le$$ ≤ 20 GPa).

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Development of Novel Lightweight Dual-Phase Al-Ti-Cr-Mn-V Medium-Entropy Alloys with High Strength and Ductility

Entropy ◽

10.3390/e22010074 ◽

2020 ◽

Vol 22 (1) ◽

pp. 74

Author(s):

Yu-Chin Liao ◽

Po-Sung Chen ◽

Chao-Hsiu Li ◽

Pei-Hua Tsai ◽

Jason Jang ◽

...

Keyword(s):

Compression Strength ◽

High Strength ◽

Alloy System ◽

Dual Phase ◽

Face Centered Cubic ◽

Compression Tests ◽

Arc Melting ◽

Face Centered ◽

Fcc Phase ◽

Strength And Ductility

A novel lightweight Al-Ti-Cr-Mn-V medium-entropy alloy (MEA) system was developed using a nonequiatiomic approach and alloys were produced through arc melting and drop casting. These alloys comprised a body-centered cubic (BCC) and face-centered cubic (FCC) dual phase with a density of approximately 4.5 g/cm3. However, the fraction of the BCC phase and morphology of the FCC phase can be controlled by incorporating other elements. The results of compression tests indicated that these Al-Ti-Cr-Mn-V alloys exhibited a prominent compression strength (~1940 MPa) and ductility (~30%). Moreover, homogenized samples maintained a high compression strength of 1900 MPa and similar ductility (30%). Due to the high specific compressive strength (0.433 GPa·g/cm3) and excellent combination of strength and ductility, the cast lightweight Al-Ti-Cr-Mn-V MEAs are a promising alloy system for application in transportation and energy industries.

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High-Temperature Deformation Behavior and Microstructural Characterization of Ti-35421 Titanium Alloy

Materials ◽

10.3390/ma13163623 ◽

2020 ◽

Vol 13 (16) ◽

pp. 3623 ◽

Cited By ~ 2

Author(s):

Danying Zhou ◽

Hua Gao ◽

Yanhua Guo ◽

Ying Wang ◽

Yuecheng Dong ◽

...

Keyword(s):

Titanium Alloy ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Deformation Behavior ◽

Deformation Temperature ◽

Phase Region ◽

Temperature Deformation ◽

Β Phase ◽

Α Phase

A self-designed Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt%) titanium alloy is a new type of low-cost high strength titanium alloy. In order to understand the hot deformation behavior of Ti-35421 alloy, isothermal compression tests were carried out under a deformation temperature range of 750–930 °C with a strain rate range of 0.01–10 s−1 in this study. Electron backscatter diffraction (EBSD) was used to characterize the microstructure prior to and post hot deformation. The results show that the stress–strain curves have obvious yielding behavior at a high strain rate (>0.1 s−1). As the deformation temperature increases and the strain rate decreases, the α phase content gradually decreases in the α + β phase region. Meanwhile, spheroidization and precipitation of α phase are prone to occur in the α + β phase region. From the EBSD analysis, the volume fraction of recrystallized grains was very low, so dynamic recovery (DRV) is the dominant deformation mechanism of Ti-35421 alloy. In addition to DRV, Ti-35421 alloy is more likely to occur in continuous dynamic recrystallization (CDRX) than discontinuous dynamic recrystallization (DDRX).

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Effect of Mn Addition on the Microstructures and Mechanical Properties of CoCrFeNiPd High Entropy Alloy

Entropy ◽

10.3390/e21030288 ◽

2019 ◽

Vol 21 (3) ◽

pp. 288

Author(s):

Yiming Tan ◽

Jinshan Li ◽

Jun Wang ◽

Hongchao Kou

Keyword(s):

Intermetallic Compound ◽

Interface Energy ◽

High Entropy Alloy ◽

Strengthening Effect ◽

Face Centered Cubic ◽

Liquid Interfaces ◽

High Entropy ◽

Single Face ◽

Face Centered ◽

Fcc Phase

CoCrFeNiPdMnx (x = 0, 0.2, 0.4, 0.6, 0.8) high entropy alloys (HEAs) were prepared and characterized. With an increase in Mn addition, the microstructures changed from dendrites (CoCrFeNiPd with a single face-centered-cubic (FCC) phase) to divorced eutectics (CoCrFeNiPdMn0.2 and CoCrFeNiPdMn0.4), to hypoeutectic microstructures (CoCrFeNiPdMn0.6), and finally to seaweed eutectic dendrites (CoCrFeNiPdMn0.8). The addition of Mn might change the interface energy anisotropy of both the FCC/liquid and MnPd-rich intermetallic compound/liquid interfaces, thus forming the seaweed eutectic dendrites. The hardness of the FCC phase was found to be highly related to the solute strengthening effect, the formation of nanotwins and the transition from CoCrFeNiPd-rich to CoCrFeNi-rich FCC phase. Hierarchical nanotwins were found in the MnPd-rich intermetallic compound and a decrease in either the spacing of primary twins or secondary twins led to an increase in hardness. The designing rules of EHEAs were discussed and the pseudo binary method was revised accordingly.

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Nearly Dislocation-Free APB Termination at Pure Grain Boundary Step Defects in L10 Alloys

MRS Proceedings ◽

10.1557/proc-319-305 ◽

1993 ◽

Vol 319 ◽

Author(s):

Abha Singh ◽

A.H. King

Keyword(s):

High Temperature ◽

Grain Boundary ◽

Tetragonal Phase ◽

Cubic Phase ◽

Face Centered Cubic ◽

Antiphase Boundaries ◽

New Type ◽

Face Centered ◽

Fcc Phase ◽

Step Defect

AbstractL10 alloys typically derive from a high-temperature, disordered fcc phase. For example, CuAu has a face centered tetragonal structure below 380°C and is derived from its high temperature, disordered face centered cubic phase. As the material transforms from the disordered fcc phase to the ordered tetragonal phase, the four distinct Σ3 fcc twin misorientations generate twelve distinct tetragonal twin misorientations, four being characterized as Σ3 and eight as Σ6. Of particular interest is the Σ6 structure because it is possible to terminate lattice antiphase boundaries without dislocations at this interface. A pure step defect at the interface can accommodate the APB termination due to anti-site coincidence (coincidence between copper and gold sites). We term these defects “antiphase steps”. The antiphase step is a new type of interfacial defect that has not been described by other workers. The possibility of forming antiphase steps in ordered L10 alloys is related to even-Σ interfaces. Since the Σ6 boundary is common in the ordered phase, the formation of dislocation-free APB terminations may be important in L10 alloys.

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Ozone-Based Atomic Layer Deposition of HfO2 and HfxSi1-xO2 and Film Characterization

MRS Proceedings ◽

10.1557/proc-811-d7.4 ◽

2004 ◽

Vol 811 ◽

Author(s):

Yoshihide Senzaki ◽

Seung Park ◽

Douglas Tweet ◽

John F. Conley ◽

Yoshi Ono

Keyword(s):

Atomic Layer ◽

Optical Measurements ◽

Face Centered Cubic ◽

Hafnium Silicate ◽

X Ray ◽

Layer Deposition ◽

Face Centered ◽

Fcc Phase ◽

20 Nm ◽

Fcc Structure

Abstract:New ALD processes for hafnium silicate films have been developed at Aviza Technology by co-injection of tetrakis(ethylmethylamino)hafnium and tetrakis(ethylmethylamino)silicon precursors. Alternating pulses of the Hf/Si precursor vapor mixture and ozone allow process temperatures below 400°C to grow HfxSi1-xO2 films. Film characterization, including film density, crystallinity, and thermal anneal effect, was performed on five 20 nm thick HfxSi1-xO2 films where x = 0.2, 0.4, 0.6, 0.8, 1.0. X-ray measurements revealed the film densities and thicknesses for the as-deposited and 1000°C annealed samples. The densification with anneals seen in the optical measurements were confirmed. The as-deposited amorphous HfO2 and Hf0.8Si0.2O2 were crystallized after a 600°C anneal. The HfO2 formed the well known monoclinic phase while the silicate formed a face-centered-cubic (fcc) structure. This fcc phase has only recently been mentioned in the literature [1].

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Grain Growth and Mechanical Properties of Nanograined Bulk Fe-25Ni Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.3459 ◽

2005 ◽

Vol 475-479 ◽

pp. 3459-3462

Author(s):

Hong Bin Wang ◽

Xiao Yu Wang ◽

J.H. Zhang ◽

T.Y. Hsu

Keyword(s):

Mechanical Properties ◽

Grain Growth ◽

Coarse Grained ◽

Growth Exponent ◽

Face Centered Cubic ◽

X Ray Diffraction ◽

Ni Alloy ◽

Face Centered ◽

Fcc Phase

The grain growth and mechanical properties of nanograined bulk Fe-25at%Ni alloy prepared by an inert gas condensation and in-situ warm consolidation technique were investigated. About 43% high temperature face-centered-cubic (FCC) phase and 57% low temperature body-centered-cubic (BCC) phase were observed in the sample at room temperature, which was significantly different from that of the corresponding conventional coarse-grained alloy. The in-situ X-ray diffraction results show that the start and the finish temperature of BCC to FCC phase transformation are 450°C and 600°C, respectively. The isothermal grain growth exponent n from t k D D n n ¢ = − 1 0 1 for nanograined single FCC phase Fe-25at%Ni alloy is 0.38 at 750 °C . The mechanical properties changing with the grain size were studied by means of microindentation test.

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Synthesis and characterization of nanostructured CeO2 with dyes adsorption property

Processing and Application of Ceramics ◽

10.2298/pac1401039z ◽

2014 ◽

Vol 8 (1) ◽

pp. 39-46 ◽

Cited By ~ 20

Author(s):

Oman Zuas ◽

Haznan Abimanyu ◽

Widayanti Wibowo

Keyword(s):

Aqueous Solution ◽

Organic Dyes ◽

Adsorption Property ◽

Average Diameter ◽

Precipitation Method ◽

Face Centered Cubic ◽

Experimental Conditions ◽

Face Centered ◽

Fcc Phase ◽

Dyes Adsorption

The nanostructured cerium dioxide (CeO2) has been successfully fabricated using a simple precipitation method. Its characteristics were evaluated using TG-DTA, DR-UV-Vis, XRD, FTIR and TEM. The results showed that the nanostructured CeO2 has high purity and good crystalline nature, with face centered cubic (fcc) phase and the average diameter of CeO2 single crystal about 14 nm. Performance evaluation of the synthesized CeO2 samples showed that the nanostructured CeO2 has a strong adsorption toward acid orange-10 (AO-10) and congo red (CR) in aqueous solution. Under given experimental conditions (dye concentration of 15 mg/l, adsorbent dosage of 1 g/l, reaction temperature of 30 ? 1?C), it was estimated that the adsorption equilibrium for AO-10 and CR occurred at 60 min and 90 min of reaction time, respectively, with total removal of 96.82% for AO-10 dye and 93.55% for CR dye. The results suggested that the CeO2 nanopowder could be potentially used as an efficient adsorbent for the removal of synthetic organic dyes in aqueous solution and may address for future concern in the area.

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Обнаружение новой фазы типа B1 в монокристаллах магнитомягких сплавов Fe-Al и Fe-Ga

Физика твердого тела ◽

10.21883/ftt.2019.11.48398.525 ◽

2019 ◽

Vol 61 (11) ◽

pp. 2000 ◽

Cited By ~ 1

Author(s):

Ю.П. Черненков ◽

Н.В. Ершов ◽

В.А. Лукшина

Keyword(s):

Volume Fraction ◽

Ferromagnetic State ◽

Aluminum Concentration ◽

Al Alloy ◽

Alloy Sample ◽

Face Centered Cubic ◽

Bcc Lattice ◽

Fcc Lattice ◽

Face Centered ◽

Fcc Phase

AbstractThe atomic structure of Fe–Al (7 and 9 at % Al) and Fe–Ga (18 at % Ga) alloys is studied by X‑ray diffraction using a laboratory four-circle diffractometer. After refining annealing, single-crystal alloy samples were annealed in the ferromagnetic state ( T < T _C). One sample of the Fe–18 at % Ga alloy, after short holding in the paramagnetic state ( T > T _C), was quenched in room temperature water. Earlier, the authors reported on the peculiarities of the ordering of alloying atoms in B 2 and D 0_3 phase structures in quenched and annealed samples of these alloys. Here, we present and discuss the results of our observations in these alloys of a new phase with a face-centered cubic (fcc) lattice ( B 1-type structure with NaCl prototype and unit cell parameter ~5.2 nm). The fcc phase appears in the Fe–Al alloy as the aluminum concentration increases from 7 to 9 at %; it is observed in the Fe–18 at % Ga alloy, and its volume fraction increases after annealing in the ferromagnetic state in comparison with a quenched alloy sample. In these alloys (9 at % Al) and (18 at % Ga), different ways of embedding fcc crystals in the bcc phase of single crystals are realized; i.e., the axes of the fcc lattice are directed in four different ways relative to the axes of the bcc lattice.

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