scholarly journals Strain-hardening properties of the high-entropy alloy MoNbTaTiVZr processed by high-pressure torsion

2021 ◽  
Author(s):  
Chuyi Duan ◽  
Marius Reiberg ◽  
Peter Kutlesa ◽  
Xiaohu Li ◽  
Reinhard Pippan ◽  
...  
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
High Entropy Alloy ◽  
Dual Phase ◽  
Rich Phase ◽  
High Entropy ◽  
Elemental Concentrations ◽  
Arc Melting ◽  
Cast Condition

AbstractAn equiatomic MoNbTaTiVZr refractory high-entropy alloy (HEA) produced by arc melting was processed by high-pressure torsion (HPT) at room temperature. Thermodynamic calculations and experimental results indicated a dual-phase microstructure composed of about 85% BCC Zr-depleted and 15% BCC Zr-rich phase in the as-cast condition. HPT causes grain refinement and an increase in dislocation density without the formation of new phases. After four revolutions, the Zr-depleted phase was hardened to $$\sim $$ ∼ 540 HV, while the Zr-rich phase exhibited softening with a decrease in hardness to $$\sim $$ ∼ 480 HV. The occurrence of a vortex-like microstructure and the analysis of elemental concentrations indicated a shear-induced mechanical homogenization, which was supposed to be the cause of the observed softening.

scholarly journals Microstructure, Texture, and Strength Development during High-Pressure Torsion of CrMnFeCoNi High-Entropy Alloy

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 336 ◽  
Author(s):  
Werner Skrotzki ◽  
Aurimas Pukenas ◽  
Eva Odor ◽  
Bertalan Joni ◽  
Tamas Ungar ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Strength Development ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
X Ray ◽  
High Entropy ◽  
Face Centered

The equiatomic face-centered cubic high-entropy alloy CrMnFeCoNi was severely deformed at room and liquid nitrogen temperature by high-pressure torsion up to shear strains of about 170. Its microstructure was analyzed by X-ray line profile analysis and transmission electron microscopy and its texture by X-ray microdiffraction. Microhardness measurements, after severe plastic deformation, were done at room temperature. It is shown that at a shear strain of about 20, a steady state grain size of 24 nm, and a dislocation density of the order of 1016 m−2 is reached. The dislocations are mainly screw-type with low dipole character. Mechanical twinning at room temperature is replaced by a martensitic phase transformation at 77 K. The texture developed at room temperature is typical for sheared face-centered cubic nanocrystalline metals, but it is extremely weak and becomes almost random after high-pressure torsion at 77 K. The strength of the nanocrystalline material produced by high-pressure torsion at 77 K is lower than that produced at room temperature. The results are discussed in terms of different mechanisms of deformation, including dislocation generation and propagation, twinning, grain boundary sliding, and phase transformation.

scholarly journals On prominent TRIP effect and non-basal slip in a TWIP high entropy alloy during high-pressure torsion processing

2021 ◽  
pp. 111284
Author(s):  
A.K. Chandan ◽  
P.T. Hung ◽  
K. Kishore ◽  
M. Kawasaki ◽  
J. Chakraborty ◽  
...  
Keyword(s):  
High Pressure ◽  
Basal Slip ◽  
High Pressure Torsion ◽  
High Entropy Alloy ◽  
Trip Effect ◽  
High Entropy

scholarly journals Evolution of microstructure and hardness in Hf25Nb25Ti25Zr25 high-entropy alloy during high-pressure torsion

2019 ◽  
Vol 788 ◽  
pp. 318-328 ◽  
Author(s):  
Jenő Gubicza ◽  
Anita Heczel ◽  
Megumi Kawasaki ◽  
Jae-Kyung Han ◽  
Yakai Zhao ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Evolution Of Microstructure

scholarly journals Laser Beam Welding of a Low Density Refractory High Entropy Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1351 ◽  
Author(s):  
Evgeniya Panina ◽  
Nikita Yurchenko ◽  
Sergey Zherebtsov ◽  
Nikita Stepanov ◽  
Gennady Salishchev ◽  
...  
Keyword(s):  
Laser Beam ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Laser Beam Welding ◽  
Base Material ◽  
Laves Phase ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Grains Refinement ◽  
Cast Condition

The effect of laser beam welding on the structure and properties of a Ti1.89NbCrV0.56 refractory high entropy alloy was studied. In particular, the effect of different pre-heating temperatures was examined. Due to the low ductility of the material, laser beam welding at room temperature resulted in the formations of hot cracks. Sound butt joints without cracks were produced using pre-heating to T ≥ 600 °C. In the initial as-cast condition, the alloy consisted of coarse bcc grains with a small amount of lens-shaped C15 Laves phase particles. A columnar microstructure was formed in the welds; the thickness of the grains increased with the temperature of pre-heating before welding. The Laves phase particles were formed in the seams after welding at 600 °C or 800 °C, however, these particles were not observed after welding at room temperature or at 400 °C. Soaking at elevated temperatures did not change the microstructure of the base material considerably, however, “additional” small Laves particles formed at 600 °C or 800 °C. Tensile test of welded specimens performed at 750 °C resulted in the fracture of the base material because of the higher hardness of the welds. The latter can be associated with the bcc grains refinement in the seams.

Nanomechanical behavior and structural stability of a nanocrystalline CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

2015 ◽  
Vol 30 (18) ◽  
pp. 2804-2815 ◽  
Author(s):  
Dong-Hyun Lee ◽  
In-Chul Choi ◽  
Moo-Young Seok ◽  
Junyang He ◽  
Zhaoping Lu ◽  
...  
Keyword(s):  
High Pressure ◽  
Structural Stability ◽  
High Pressure Torsion ◽  
High Entropy Alloy ◽  
High Entropy ◽  
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