scholarly journals Influence of Manufacturing Conditions on Inclusion Characteristics and Mechanical Properties of FeCrNiMnCo Alloy

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1286
Author(s):  
Nuri Choi ◽  
Nokeun Park ◽  
Jin-kyung Kim ◽  
Andrey V. Karasev ◽  
Pär G. Jönsson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impurity Content ◽  
Inert Gas ◽  
Molten Alloy ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Atmospheric Conditions ◽  
Air Exposure ◽  
High Entropy ◽  
Gas Atmosphere

Three CoCrFeMnNi high-entropy alloys (HEAs) were produced by vacuum induction melting, induction melting under inert gas atmosphere, and melting under inert gas atmosphere followed by air exposure, respectively. The different manufacturing conditions for the three investigated alloys resulted in different levels and types of inclusions. The alloys melted under vacuum or inert gas contained Al2O3 inclusions formed by impurity Al, due to its high oxidation tendency. The molten alloy exposed in air showed an excessive oxidation. During oxidation of the molten alloy in air, impurity Al was initially oxidized, and fine MnCr2O4 inclusions were formed rather than pure Al2O3 inclusions. This difference was analyzed based on thermodynamic calculations. Specifically, the influence of impurity content on the inclusion characteristics was investigated for the three HEAs. Moreover, the inclusion characteristics were found to have an influence on mechanical properties of the alloys also. In air-exposed HEA, smaller inclusions were formed, resulting in a higher dislocation density at the matrix/inclusion interface and thus strengthening of the HEA. Thus, it is proposed that atmospheric conditions could be an important factor to control the inclusion characteristics and to form fine inclusion particles, which could improve the mechanical properties of HEAs.

scholarly journals The Effect of Zr Addition on Melting Temperature, Microstructure, Recrystallization and Mechanical Properties of a Cantor High Entropy Alloy

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5994
Author(s):  
Enrico Gianfranco Campari ◽  
Angelo Casagrande ◽  
Elena Colombini ◽  
Magdalena Lassinantti Gualtieri ◽  
Paolo Veronesi
Keyword(s):  
Mechanical Properties ◽  
Melting Temperature ◽  
Recrystallization Temperature ◽  
Vacuum Induction Melting ◽  
High Entropy Alloy ◽  
Second Phase ◽  
Induction Melting ◽  
High Entropy ◽  
Zr Addition ◽  
Cold Rolled

The effect of Zr addition on the melting temperature of the CoCrFeMnNi High Entropy Alloy (HEA), known as the “Cantor’s Alloy”, is investigated, together with its micro-structure, mechanical properties and thermomechanical recrystallization process. The base and Zr-modified alloys are obtained by vacuum induction melting of mechanically pre-alloyed powders. Raw materials are then cold rolled and annealed. recrystallization occurred during the heat treatment of the cold-rolled HEA. The alloys are characterized by X-ray diffraction, electron microscopy, thermal analyses, mechanical spectroscopy and indentation measures. The main advantages of Zr addition are: (1) a fast vacuum induction melting process; (2) the lower melting temperature, due to Zr eutectics formation with all the Cantor’s alloy elements; (3) the good chemical alloy homogeneity; and (4) the mechanical properties improvement of re-crystallized grains with a coherent structure. The crystallographic lattice of both alloys results in FCC. The Zr-modified HEA presents a higher recrystallization temperature and smaller grain size after recrystallization with respect to the Cantor’s alloy, with precipitation of a coherent second phase, which enhances the alloy hardness and strength.

scholarly journals The Effect of Zr Addition on Melting Temperature, Microstructure, Recrystallization and Mechanical Properties of a Cantor High Entropy Alloy

2021 ◽  
Author(s):  
Enrico Gianfranco Campari ◽  
Angelo Casagrande ◽  
E. Colombini ◽  
Magdalena Gualtieri ◽  
Paolo Veronesi
Keyword(s):  
Mechanical Properties ◽  
Melting Temperature ◽  
Recrystallization Temperature ◽  
Vacuum Induction Melting ◽  
High Entropy Alloy ◽  
Second Phase ◽  
Induction Melting ◽  
Recrystallization Process ◽  
High Entropy ◽  
Zr Addition

The effect of Zr addition on the melting temperature of the CoCrFeMnNi High Entropy Alloy (HEA), known as the “Cantor’s Alloy”, is investigated, together with its microstructure, mechan-ical properties and thermo-mechanical recrystallization process. The base and Zr-modified al-loys are obtained by vacuum induction melting of mechanically pre-alloyed powders followed by recrystallization. The alloys were characterized by X-ray diffraction, scanning and transmis-sion electron microscopy, thermal analyses, mechanical spectroscopy and indentation measures. The main advantages of Zr addition are: 1) a fast vacuum induction melting (VIM) process; 2) the lower melting temperature, due to Zr eutectics formation with all the Cantor’s alloy elements; 3) the good chemical alloy homogeneity; 4) the mechanical properties improvement of recrystallized grains with a coherent structure. The crystallographic lattice of both alloys resulted to be FCC. Results demonstrate that the Zr-modified HEA presents a higher recrystallization temperature and smaller grain size after recrystallization with respect to the Cantor’s alloy, with precipita-tion of a coherent second phase which enhance the alloy hardness and strength, while maintaining a good tensile ductility.

scholarly journals Effect of SLM Processing Parameters on Microstructures and Mechanical Properties of Al0.5CoCrFeNi High Entropy Alloys

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 292 ◽  
Author(s):  
Kun Sun ◽  
Weixiang Peng ◽  
Longlong Yang ◽  
Liang Fang
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Process Parameters ◽  
Laser Power ◽  
Scanning Speed ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Hatch Spacing

Selective laser melting (SLM) to fabricate Al0.5CoCrFeNi high entropy alloys with pre-mixed powders was studied in this paper. The influences of process parameters including laser power, scanning speed, and hatch spacing on the relative density of high-entropy alloys (HEAs) were investigated. A relative density of 99.92% can be achieved by optimizing the SLM process parameters with laser power 320 W, scanning speed 800 mm/s, and hatch spacing of 60 μm, respectively. Moreover, the microstructure of the HEAs was also studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD). It was found that the microstructure of the HEAs was only composed of face-centered cubic and body-centered cubic phases, without complex intermetallic compounds. The mechanical properties of the HEAs were also characterized. At ambient temperature, the alloys had a high yield strength of about 609 MPa, tensile strength about 878 MPa, and hardness about 270 HV. Through a comparison with the corresponding alloys fabricated by vacuum induction melting, it can be concluded that the high entropy alloys fabricated by SLM had fine microstructures and improved mechanical properties.

Influences of Solution Temperatures on Microstructure and Mechanical Properties of near α Titanium Alloy

2021 ◽  
Vol 1035 ◽  
pp. 89-95
Author(s):  
Chao Tan ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Xiao Zhao Ma ◽  
Zi An Yang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
High Temperature ◽  
Room Temperature ◽  
Solution Temperature ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Β Phase ◽  
Α Phase ◽  
New Type

A new type of Ti-Al-Sn-Zr-Mo-Si series high temperature titanium alloy was prepared by a water-cooled copper crucible vacuum induction melting method, and its phase transition point was determined by differential thermal analysis to be Tβ = 1017 °C. The influences of solution temperature on the microstructures and mechanical properties of the as-forged high temperature titanium alloy were studied. XRD results illustrated that the phase composition of the alloy after different heat treatments was mainly α phase and β phase. The microstructures showed that with the increase of the solution temperature, the content of the primary α phase gradually reduced, the β transformation structure increased by degrees, then, the number and size of secondary α phase increased obviously. The tensile results at room temperature (RT) illustrated that as the solution temperature increased, the strength of the alloy gradually increased, and the plasticity decreased slightly. The results of tensile test at 650 °C illustrated that the strength of the alloy enhanced with the increase of solution temperature, the plasticity decreased first and then increased, when the solution temperature increased to 1000 °C, the alloy had the best comprehensive mechanical properties, the tensile strength reached 714.01 MPa and the elongation was 8.48 %. Based on the room temperature and high temperature properties of the alloy, the best heat treatment process is finally determined as: 1000 °C/1 h/AC+650 °C/6 h/AC.

Effect of Interstitial Elements on the Cryogenic Mechanical Behavior of FCC High Entropy Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1386-1391
Author(s):  
Anastasia Semenyuk ◽  
Margarita Klimova ◽  
Sergey Zherebtsov ◽  
Nikita Stepanov
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Thermomechanical Processing ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
High Entropy ◽  
C And N ◽  
Interstitial Elements

High entropy alloys (HEAs) with face-centered cubic (fcc) structure, namely equiatomic CoCrFeMnNi alloy, have attracted considerable attention because of impressive cryogenic mechanical properties – strength, ductility, and fracture toughness. Further increase of the properties can be achieved, for example, by proper alloying. A particularly attractive option is the addition of interstitial elements like carbon or nitrogen. In present work, a series of CoCrFeMnNi-based alloys with different amounts of C and N (0-2 at.%) was prepared by induction melting. The alloys doped with C had lower Cr content to increase the solubility of carbon in the fcc solid solution. It was revealed that the solid solution strengthening effect of both C and N is significantly increased when the testing temperature decreases from 293K to 77K. The effect of thermomechanical processing on the structure and mechanical properties of the alloys is analyzed.

Study to Microstructure and Mechanical Properties of Mg Containing High Entropy Alloys

2010 ◽  
Vol 650 ◽  
pp. 265-271 ◽  
Author(s):  
Rui Li ◽  
Jia Cheng Gao ◽  
Ke Fan
Keyword(s):  
Mechanical Properties ◽  
Testing Machine ◽  
High Hardness ◽  
Material Strength ◽  
High Entropy Alloy ◽  
Icosahedral Quasicrystal ◽  
Induction Melting ◽  
High Entropy ◽  
Microstructure And Mechanical Properties ◽  
Thermal Analyzer

In this paper, alloys with compositions of Mgx(MnAlZnCu)100-x (x: atomic percentage; x=20, 33, 43, 45.6 and 50 respectively) were designed by using the strategy of equiatomic ratio and high entropy of mixing. Microstructure and mechanical properties of the new high entropy alloy were studied. The alloys were prepared by induction melting and then were cast in a copper mold in air. The alloy samples were examined by microhardness tester, XRD, SEM, thermal analyzer and testing machine for material strength. Alloys were composed mainly of h.c.p phase and Al-Mn icosahedral quasicrystal phases. The alloys exhibited moderate densities which were from 4.29g•cm-3 to 2.20g•cm-3, high hardness (429HV-178HV) and high compression strength (500MPa-400MPa) at room temperature. The extensibility was increased with Mg from 20at% (atomic percentage) to 50at%.

Synthesis and Purification of Silicon Carbide Powders for Crystal Growth

2012 ◽  
Vol 717-720 ◽  
pp. 37-40 ◽  
Author(s):  
Ta Ching Hsiao ◽  
Sheng Tsao
Keyword(s):  
Silicon Carbide ◽  
Crystal Growth ◽  
Acid Leaching ◽  
Melting Furnace ◽  
Impurity Content ◽  
Low Pressure ◽  
Free Carbon ◽  
Vacuum Induction Melting ◽  
Carbide Formation ◽  
Induction Melting

Silicon carbide powders were prepared in a vacuum induction melting furnace (VIM). Silica and silicon were used as sources of silicon, and graphite powder was used a source of carbon. Pressures of 0.1 and 0.01 atm were selected as the operation conditions, and different silicon carbide powders were prepared. Free carbon and remnant silica were removed by high-temperature baking in air and acid leaching. Low-pressure powders show better crystallinity; moreover, free carbon and silica were rarely found in the product after baking and leaching. The low-pressure grains were prismatic whereas the high-pressure grains were porous. This shows that pressure is a critical parameter in silicon carbide formation, and low-pressure makes the low-temperature synthesis of silicon carbide feasible. Glow discharge mass spectra were used to analyze the impurity content in silicon carbide powders. After baking and leaching, the purity is increased from 3N5 (99.95 wt.%) to 4N5 (99.995 wt.%). Further purification procedures will be combined to meet the quality requirements for crystal growth.

Study on the Microstructure and Properties of Low Cost TiFeAl Alloy

2013 ◽  
Vol 477-478 ◽  
pp. 1288-1292
Author(s):  
Bo Long Li ◽  
Tong Liu ◽  
Jie Yuan ◽  
Zuo Ren Nie
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Low Cost ◽  
High Strength ◽  
Al Alloys ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Β Phase ◽  
Transmission Electron ◽  
Solution Strengthening

The high strength and low cost Ti-Fe based alloy was produced by double vacuum induction melting method followed by hot deformation. The microstructure has been investigated by Optical Microscopy, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The microstructure of as-forged alloy is composed of α and β phase without the precipitation of TiFe intermetallic compound. The Ti-Fe-Al alloys show good comprehensive mechanical properties, demonstrating ultimate tensile strength of 1100MPa and elongation above10%. The results indicate the Fe is a good candidate for solution strengthening and simultaneously increasing ductility in titanium alloys. Effect of the Fe and Al elements on the microstructure and mechanical properties have been discussed.

scholarly journals Effect of Ta and W Additions on Microstructure and Mechanical Properties of Tilt-Cast Ti-45Al-5Nb-2C Alloy

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2052
Author(s):  
Juraj Lapin ◽  
Kateryna Kamyshnykova
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Volume Fraction ◽  
Vacuum Induction Melting ◽  
Nominal Composition ◽  
Induction Melting ◽  
Carbide Phases ◽  
Microstructure And Mechanical Properties ◽  
B2 Phase ◽  
Carbide Particles

The effect of Ta and W additions on microstructure and mechanical properties of tilt-cast Ti-45Al-5Nb-2C (at.%) alloy was investigated. Three alloys with nominal composition Ti-45Al-5Nb-2C-2X (in at.%), where X is Ta or W, were prepared by vacuum induction melting in graphite crucibles followed by tilt casting into graphite moulds. The microstructure of the tilt-cast alloys consists of the α2(Ti3Al) + γ(TiAl) lamellar grains, single γ phase, (Ti,Nb,X)2AlC particles with a small amount of (Ti,Nb,X)C, and β/B2 phase identified only in W containing alloy. The EDS analysis shows that Ta segregates into the carbide particles and reduces dissolution of Nb in both (Ti,Nb,Ta)C and (Ti,Nb,Ta)2AlC phases. The alloying with W reduces Nb content in both carbide phases and leads to stabilisation of β/B2 phase in the lamellar α2 + γ regions. The alloying with Ta and W does not affect the volume fraction of the carbide particles but influences their size and morphology. While the alloying with Ta and W has no significant effect on Vickers hardness and the indentation elastic modulus of the studied alloys, the addition of Ta affects the nanohardness and elastic modulus of the (Ti,Nb,Ta)2AlC phase. The addition of W significantly increases the Vickers microhardness of the lamellar α2 + γ regions.

Effect of Rolling Deformation to Microstructure and Properties of Mg-8.5Li-1Al-1Ce Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 924-927
Author(s):  
Wang Tao ◽  
Mi Lin Zhang ◽  
Shu Jin Zhao ◽  
Chun Mei Song ◽  
Cheng Ju
Keyword(s):  
Mechanical Properties ◽  
Basal Slip ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Slip Systems ◽  
Melting Method ◽  
Β Phase ◽  
Pyramidal Slip ◽  
Α Phase ◽  
Rolling Deformation

Mg-8.5Li-1Al-1Ce alloys were prepared with vacuum induction melting method. Uniaxial rolling deformation of alloys was obtained by two-roll milling. The effect of rolling deformation was studied on the microstructure and mechanical properties of Mg-8.5Li-1Al-1Ce. The results show that the microstructure morphologies of α-phase, β-phase and Al2Ce-phase go through different changes under different rolling percentages, and the mechanical properties are improved with increasing deformation. Besides the basal slip system, the prism and pyramidal slip systems are also activated in α(Mg) phase, with all the slip systems in β(Li) phase being uniformly activated.

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