scholarly journals Effect of low temperature rolling on mechanical properties and corrosion resistance of CrCoNi medium entropy alloy

Author(s):  
Jinliang Chen ◽  
Zhongxue Feng ◽  
Jianhong Yi ◽  
Jun Yang

Abstract Abstract: For the casted CrCoNi medium entropy alloy melted by magnetic levitation, the deformation was carried out in 4 passes under the condition of liquid nitrogen temperature (-196°C), the total reduction was 50%,The microstructure and properties were analyzed after liquid nitrogen low temperature rolled. The experimental data showed that the phase structure of the alloy was not changed under the low-temperature rolling. The grains, crushed and refined, were elongated along the rolling direction. With the increasing of passes and reduction, the tensile strength increased from 585 MPa to 1359 MPa, while the elongation decreased from 37.8% to 5.9%. work With the increasing of work hardening,the tensile strength of the CrCoNi medium entropy alloy gradually increased, while the plasticity dramatic decreased. At the same time,the corrosion resistance of the CrCoNi medium entropy alloy was improved by low temperature cold rolled. The corrosion resistance of as-cast and rolled CrCoNi was much better than 304 stainless steel.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yun Tan ◽  
Wei Li ◽  
Aiwen Li ◽  
Xiaofang Shi

AbstractThe microstructure evolution, texture, mechanical behavior and twin deformation of the ECAPed Mg–2Y–0.6Nd–0.6Zr alloy at room and liquid nitrogen temperature were investigated by rolling samples. The ECAP processed material appeared the texture of 45° to the extrusion direction and its yield strength reached 93.6 MPa. The results showed that cryorolling encourages twinning in Mg–2Y–0.6Nd–0.6Zr alloy, enhancing the tensile strength and texture. Activation of {10–12} twinning during rolling was found to be more pronounced in the cryorolled samples than in the cold rolled samples owing to a lower temperature. As a result, the cryorolled samples had more twins than and cold rolled ones, the proportion of twin areas of room temperature rolling and ultra-low temperature rolling were: 2.45% and 4.23%.


2007 ◽  
Vol 550 ◽  
pp. 283-288
Author(s):  
J. Kusnierz

The changes in the tensile properties, in relation to the phenomenon of shear banding are investigated in copper, rolled at liquid nitrogen temperature and then recrystallized, after initial processing by Equal-Channel Angular Extrusion (ECAE) at room temperature. Increases in ductility and strength up to the fourth pass of ECAE processing were noted, then a decrease of both properties was observed. The decrease was accompanied by twinning and shear banding. In rolled samples, pre-cooled down to the temperature of liquid nitrogen and initially recrystallized, the twinning and shear banding mechanisms were the most probable mechanisms responsible for lowering the mechanical properties.


2013 ◽  
Vol 721 ◽  
pp. 278-281
Author(s):  
Jun Ma

t has been investigated that the interaction force in hybrid magnetic levitation systems with two GdBCO bulk superconductors and two permanent magnets system and a cubic permanent magnet (PM2) and a cubic permanent magnet (PM3) system in their coaxial configuration at liquid nitrogen temperature. The two single-domain GdBCO samples are of φ20mm and 10mm in thickness, the permanent magnet PM1 is of rectangular parallelepiped shape, the permanent magnets PM2 and PM3 are of cubic shape; the system placed on the middle of system and their coaxial configuration; It is found that the maximum levitation force decreases from 40.6N to 17.8N while the distance (Dpp) between the permanent magnets is increased from 0mm to 24mm and the distance (Dsp) between the two GdBCO bulk superconductors and a cubic permanent magnet PM3 is 0mm, The results indicate that the higher levitation force can be obtained by introducing PM-PM levitation system based on scientific and reasonable design of the hybrid magnetic levitation system, which is helpful for designing and constructing superconducting magnetic levitation systems.


2015 ◽  
Vol 1 (1) ◽  
pp. 37-48
Author(s):  
Anna Andreevna Demina ◽  
A V Safonov ◽  
O A Kovalchuk ◽  
E R Zapretilina ◽  
I Yu Rodin ◽  
...  

In recent years increasingly discusses the prospects of application of high-temperature superconductors (HTS) as the winding current-carrying elements of magnetic systems for various purposes. It seems particularly attractive possibility of such systems at liquid nitrogen temperature. The article describes the prototype of module of the magnetic system which is made on the basis of high-temperature superconducting tapes, designed for the installation and testing on a working model of a static levitation. In the working model levitation of the platform carried by the interaction of the magnetic field of the assembly of permanent magnets mounted on the platform with a field similar to assemblies located in the track structure. Compact HTS module replaces the two assemblies of permanent magnets mounted on the platform. Each block of the module represents HTS racetrack coil with current inputs, power structure, positioning system and bracing which is placed in a cryostat, providing at minimum wall thickness of the required mechanical strength and thermal insulation at liquid nitrogen temperature. The prototype of unified superconducting module successfully passed preliminary tests.


2021 ◽  
Vol 2144 (1) ◽  
pp. 012010
Author(s):  
S V Zasypkin ◽  
A O Cheretaeva ◽  
M R Shafeev ◽  
D L Merson ◽  
M M Krishtal

Abstract The effect of heat treatment on the mechanical properties (hardness, plasticity, yield and tensile strength) and corrosion resistance of several cast magnesium alloys with additions of rare earth metals (Y, Nd and Gd), and their surface modification by plasma electrolytic oxidation (PEO) were investigated. It was found that the heat treatment of the alloys results information of Mg12YZn, Mg3Zn3Y2 and Mg24Y5 based LPSO-phases and causes an increase in hardness and tensile strength by 5-7 and 20-25%, respectively, but at the same time, corrosion resistance of the alloysdrops by 10-20 times. PEO of the alloys after heat treatment reduced the corrosion currents by 1-3 orders of magnitude without changing the corrosion potential.


Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1212
Author(s):  
Xiong ◽  
Yang ◽  
Deng ◽  
Li ◽  
Li ◽  
...  

The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg–7Li–3Al alloys was investigated. The results showed that the extruded Mg–7Li–3Al–xCa alloys consisted of α-Mg (hcp) + β-Li (bcc) matrix phases and Al2Ca. With increasing Ca content, the amount and morphology of the Al2Ca phase changed significantly. The grains of the extruded Mg–7Li–3Al–xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg–7Li–3Al–0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential Ecorr of −1.48742 VVSE, attributed to the formation of protective Al2Ca phases.


Author(s):  
Edgar Lara-Curzio ◽  
R. Trejo ◽  
K. L. More ◽  
P. J. Maziasz ◽  
B. A. Pint

The effects of stress, temperature and time of exposure to microturbine exhaust gases on the mechanical properties and corrosion resistance of alloys HR-120® and 230® was investigated at turbine exhaust temperatures between 620°C and 760°C. It was found that the ultimate tensile strength and ductility of alloy 230® decreased by 30% and 60%, respectively, after 500 hours exposure at 752°C. At the lowest exposure temperature of 679°C the ultimate tensile strength and ductility decreased by 10% and 25%, respectively. The ultimate tensile strength and ductility of HR-120® alloy decreased by 15% and 50%, respectively, after 500 hours exposure at 745°C. At the lowest exposure temperature of 632°C the ultimate tensile strength and ductility decreased by 10% and 23%, respectively. The microstructural changes associated with exposure to microturbine exhaust gases are analyzed and discussed.


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