scholarly journals Influence of Cold Rotary Swaging on Microstructure and Uniaxial Mechanical Behavior in Alloy 718

2021 ◽  
Author(s):  
Alexander Klumpp ◽  
Alexander Kauffmann ◽  
Sascha Seils ◽  
Stefan Dietrich ◽  
Volker Schulze
Keyword(s):  
Mechanical Behavior ◽  
Electron Backscatter Diffraction ◽  
Moderate Increase ◽  
Alloy 718 ◽  
Pronounced Increase ◽  
Rotary Swaging ◽  
Elastic Range ◽  
Nickel Based Superalloy ◽  
Tempering Treatment ◽  
Tension And Compression

AbstractIn this study, the influence of cold rotary swaging on microstructure and mechanical properties of the precipitation-strengthened nickel-based superalloy 718 (Alloy 718) was investigated. The initial stages of work-hardening were characterized by means of microhardness, electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) analyses. Furthermore, attention was devoted to the mechanical behavior at ambient and elevated temperature (550 °C) in uniaxial tension and compression. Rotary swaging to different true strains of maximum $$\varphi = 0.91$$ φ = 0.91 caused a moderate increase of microhardness and enhanced markedly the load-bearing capacity in tension, giving rise to yield strength beyond 2000 MPa. The mechanical strength $$R_{p0.2}$$ R p 0.2 in tension subsequent to rotary swaging perfectly correlates with increasing dislocation density $$\rho $$ ρ estimated from XRD in the form of a Taylor-like relationship $$R_{p0.2} \propto \sqrt{\rho }$$ R p 0.2 ∝ ρ . In compression, transient stress–strain evolution without the occurrence of a clear elastic range and distinct yield phenomenon was observed. Restoration of the elastic range, accompanied by a pronounced increase of microhardness, was obtained by a post-swaging tempering treatment at 600 °C.

scholarly journals Influence of Microstructure on Mechanical Properties of Bainitic Steels in Railway Applications

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 778 ◽  
Author(s):  
Omid Hajizad ◽  
Ankit Kumar ◽  
Zili Li ◽  
Roumen H. Petrov ◽  
Jilt Sietsma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Behavior ◽  
Mechanical Performance ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Uniaxial Tensile ◽  
Isothermal Heat Treatment

Wheel–rail contact creates high stresses in both rails and wheels, which can lead to different damage, such as plastic deformation, wear and rolling contact fatigue (RCF). It is important to use high-quality steels that are resistant to these damages. Mechanical properties and failure of steels are determined by various microstructural features, such as grain size, phase fraction, as well as spatial distribution and morphology of these phases in the microstructure. To quantify the mechanical behavior of bainitic rail steels, uniaxial tensile experiments and hardness measurements were performed. In order to characterize the influence of microstructure on the mechanical behavior, various microscopy techniques, such as light optical microscopy (LOM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), were used. Three bainitic grades industrially known as B360, B1400 plus and Cr-Bainitic together with commonly used R350HT pearlitic grade were studied. Influence of isothermal bainitic heat treatment on the microstructure and mechanical properties of the bainitic grades was investigated and compared with B360, B1400 plus, Cr-Bainitic and R350HT in as-received (AR) condition from the industry. The results show that the carbide-free bainitic steel (B360) after an isothermal heat treatment offers the best mechanical performance among these steels due to a very fine, carbide-free bainitic microstructure consisting of bainitic ferrite and retained austenite laths.

scholarly journals Molecular dynamics simulations of the mechanical behavior of alumina coated aluminum nanowires under tension and compression

RSC Advances ◽  
2020 ◽  
Vol 10 (24) ◽  
pp. 14353-14359
Author(s):  
Yudi Rosandi ◽  
Hoang-Thien Luu ◽  
Herbert M. Urbassek ◽  
Nina Gunkelmann
Keyword(s):  
Molecular Dynamics ◽  
Mechanical Behavior ◽  
Molecular Dynamics Simulations ◽  
Alumina Coatings ◽  
Tension And Compression ◽  
Dynamics Simulations

Alumina coatings increase the ductility of aluminum nanowires by reorganization of the Al–O layer and stabilization of bonds.

Influence of Environment on Mechanical Behavior of Alloy 718 at 650°C

2013 ◽  
pp. 181-188
Author(s):  
Veronique Garat ◽  
Bernard Viguier ◽  
Jean Marc Cloué ◽  
Eric Andrieu
Keyword(s):  
Mechanical Behavior ◽  
Alloy 718

scholarly journals Investigation on Sub-Solvus Recrystallization Mechanisms in an Advanced γ-γ’ Nickel-Based Superalloy GH4151

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4553
Author(s):  
Shaomin Lv ◽  
Jinbin Chen ◽  
Xinbo He ◽  
Chonglin Jia ◽  
Kang Wei ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Energy Surface ◽  
Electron Backscatter Diffraction ◽  
True Strain ◽  
Continuous Dynamic Recrystallization ◽  
Nickel Based Superalloy ◽  
Transmission Electron ◽  
Continuous Dynamic ◽  
Backscatter Diffraction

Sub-solvus dynamic recrystallization (DRX) mechanisms in an advanced γ-γ’ nickel-based superalloy GH4151 were investigated by isothermal compression experiments at 1040 °C with a strain rate of 0.1 s−1 and various true strain of 0.1, 0.3, 0.5, and 0.7, respectively. This has not been reported in literature before. The electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) technology were used for the observation of microstructure evolution and the confirmation of DRX mechanisms. The results indicate that a new dynamic recrystallization mechanism occurs during hot deformation of the hot-extruded GH4151 alloy. The nucleation mechanism can be described as such a feature, that is a primary γ’ (Ni3(Al, Ti, Nb)) precipitate embedded in a recrystallized grain existed the same crystallographic orientation, which is defined as heteroepitaxial dynamic recrystallization (HDRX). Meanwhile, the conventional DRX mechanisms, such as the discontinuous dynamic recrystallization (DDRX) characterized by bulging grain boundary and continuous dynamic recrystallization (CDRX) operated through progressive sub-grain merging and rotation, also take place during the hot deformation of the hot-extruded GH4151 alloy. In addition, the step-shaped structures can be observed at grain boundaries, which ensure the low-energy surface state during the DRX process.

Effects of Anisotropy on the Microstructural Characteristics and Mechanical Behavior of Shock-Loaded of AZ31 Alloy

2011 ◽  
Vol 284-286 ◽  
pp. 1537-1541 ◽  
Author(s):  
Min Hao ◽  
Fan Zhang ◽  
Cheng Wen Tan ◽  
Tie Jian Su ◽  
Xiao Dong Yu
Keyword(s):  
Mechanical Behavior ◽  
Strain Hardening ◽  
Electron Backscatter Diffraction ◽  
Az31 Alloy ◽  
Peak Strain ◽  
Compression Tests ◽  
Microstructural Characteristics ◽  
Post Shock ◽  
Backscatter Diffraction ◽  
Strain Hardening Rate

Effects of anisotropy on the microstructural characteristics and mechanical behavior of shock loaded of AZ31 magnesium alloy have been investigated. Using electron backscatter diffraction, tension twinning was observed in both shock loading directions along the normal (ND) and rolling directions (RD). Compression tests were carried out along ND and RD in both as-received and post-shock conditions. It indicated that the RD samples show a more notable hardening behavior compared to the as-received conditions. Moreover, it is postulated here that detwinningresults in a drop of strain-hardening rate for the ND samples under post shock reload conditions and tension twinning formed during the shock wave loading process leads to a significant moving left of the peak strain hardening rate for the RD samples under post shock reload conditions.

scholarly journals On the mechanical behavior of WS2 nanotubes under axial tension and compression

2006 ◽  
Vol 103 (3) ◽  
pp. 523-528 ◽  
Author(s):  
I. Kaplan-Ashiri ◽  
S. R. Cohen ◽  
K. Gartsman ◽  
V. Ivanovskaya ◽  
T. Heine ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Axial Tension ◽  
Tension And Compression

Atom Probe Tomography Of Interfaces

1999 ◽  
Vol 5 (S2) ◽  
pp. 118-119
Author(s):  
M. K. Miller
Keyword(s):  
Atom Probe Tomography ◽  
Small Volume ◽  
Atom Probe ◽  
Solute Segregation ◽  
Alloy 718 ◽  
Polycrystalline Nickel ◽  
Concentration Gradients ◽  
Precipitate Morphology ◽  
Probe Field ◽  
Nickel Based Superalloy

The technique of atom probe tomography (APT) enables the x, y, and z coordinates and the elemental identities of the atoms in a small volume to be determined at the atomic level. Therefore, the APT technique may be used to characterize solute segregation to interfaces and precipitation in terms of concentration gradients and precipitate morphology. This type of information may be used to optimize the design of alloys.The material that was used to illustrate the capabilities of atom probe tomography is a complex polycrystalline nickel-based superalloy, Alloy 718. The composition of this commercial superalloy is Ni- 3.2 at. % Nb, 0.96% Al, 1.15% Ti, 20.3% Fe, 21.8% Cr, 0.26% Co, 1.8% Mo, 0.16% Mn, 0.21% Si and 0.26% C. The material was characterized after a heat treatment oM h at 1038°C + 8 h at 870°C + 500 h at 600°C. Previous atom probe field ion microscopy characterizations of this material has demonstrated that there is no intragranular precipitation after the anneal at 1038°C.

scholarly journals Structure / Property (Constitutive and Dynamic Strength / Damage) Behavior of Additively Manufactured Tantalum

2018 ◽  
Vol 183 ◽  
pp. 03002
Author(s):  
George.T. Gray ◽  
Veronica Livescu ◽  
Cameron Knapp ◽  
David R. Jones ◽  
Saryu Fensin ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Damage Evolution ◽  
Electron Backscatter Diffraction ◽  
Dynamic Strength ◽  
Functional Requirements ◽  
Structure Property ◽  
Powder Bed ◽  
Static Mechanical ◽  
Backscatter Diffraction ◽  
Dynamic Damage

For Certification and qualification of an engineering component generally involves meeting engineering and physics requirements tied to its functional requirements. In this paper, the results of a study quantifying the microstructure, mechanical behavior, and the dynamic damage evolution of Tantalum (Ta) fabricated using an EOS laser-powder-bed machine are presented. The microstructure and quasi-static mechanical behavior of the AM-Ta is detailed and compared / contrasted to wrought Ta. The dynamic damage evolution and failure response of the AM-Ta material, as well as wrought Ta, was probed using flyer-plate impact driven spallation experiments. The differences in the spallation response between the AM and wrought Ta were measured using in-situ velocimetry as well as post-mortem quantification of damage in “soft-recovered” samples. The damage evolution of the AM and wrought Ta were characterized using both optical metallography and electron-backscatter diffraction.

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