scholarly journals SIMULTANEOUSLY ENHANCING MECHANICAL PROPERTIES AND ELECTRICAL CONDUCTIVITY OF CU-CR ALLOY PROCESSED BY ECAP AND DCT

2020 ◽  
Vol 26 (4) ◽  
pp. 161-165
Author(s):  
Zhu Qi Chu ◽  
Kun Wei ◽  
Li Yang ◽  
Qing Du ◽  
Wei Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Tensile Strength ◽  
Dislocation Density ◽  
Vacancy Concentration ◽  
Cryogenic Treatment ◽  
Shear Direction ◽  
Deep Cryogenic Treatment ◽  
Angular Pressing ◽  
Elongation To Failure

Mechanical properties and electrical conductivity of Cu-0.5%Cr alloy were simultaneously enhanced by combing the equal channel angular pressing (ECAP) and deep cryogenic treatment (DCT). The effect of DCT on the microstructure and properties of Cu-0.5%Cr alloy prepared by ECAP was investigated. The results show that the grains were elongated and refined along the deformation shear direction, and the dislocation density increased significantly by ECAP deformation. After the subsequent DCT, the grains were further refined, and at the same time, the dislocation density was further increased. With the increase of passes of ECAP, the microhardness and tensile strength of Cu-0.5%Cr alloy increased significantly, but the elongation to failure and electrical conductivity decreased slightly. After the DCT, the microhardness, electrical conductivity, tensile strength and elongation to failure of the Cu-0.5%Cr alloy were improved. After the ECAP (four passes) and DCT (12 h), the tensile strength, elongation to failure and electrical conductivity reached 483 MPa, 17.6% and 29%IACS respectively. The improvement of tensile properties could be attributed to the increase of dislocation density and grain refinement. The electrical conductivity was improved by the DCT due to the decrease of vacancy concentration.

Influence of Cooling Speed on the Microstructure of Particles Reinforced 7055Al Composites Subject to Regulatory Cryogenic Treatment

2014 ◽  
Vol 941-944 ◽  
pp. 314-317
Author(s):  
Guirong Li ◽  
Hong Ming Wang ◽  
Yu Hua Cui ◽  
Yue Ming Li ◽  
Cong Xiang Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Dislocation Density ◽  
Microstructural Evolution ◽  
Cryogenic Treatment ◽  
Preferred Orientation ◽  
Electronic Microscopy ◽  
Transmission Electronic Microscopy ◽  
Cooling Speed

Al3Ti and Al3Zr particles reinforced 7055Al composites were processed by cryogenic treatment with different cooling speed at 1°C/min, 3°C/min and 5°C/min. Transmission Electronic Microscopy (TEM) was mainly used to analyze the microstructural evolution of the treated samples. The results show that with the increase of cooling speed the precipitate amount and dislocation density have been increased. The precipitates orientation exhibits some preferred orientation. The mechanical properties test demonstrates that for the samples treated at 5°C/min the tensile strength and elongation has arrived at the utmost.

Effect of the electropulsing on mechanical properties and microstructure of an ECAPed AZ31 Mg alloy

2008 ◽  
Vol 23 (6) ◽  
pp. 1570-1577 ◽  
Author(s):  
X.N. Du ◽  
S.M. Yin ◽  
S.C. Liu ◽  
B.Q. Wang ◽  
J.D. Guo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Az31 Alloy ◽  
Mg Alloy ◽  
Microstructure Development ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Az31 Mg Alloy ◽  
Structures And Properties ◽  
Elongation To Failure

The mechanical properties and corresponding microstructure development of the AZ31 Mg alloy after treatment with equal channel angular pressing (ECAP) and subsequent electropulsing (ECP) was investigated. Comparing the ECAP+ECP-treated AZ31 alloy with the ECAP-treated alloy, the elongation to failure was improved significantly, while the yield stress and the ultimate tensile strength were not decreased, the grain sizes were slightly increased and more homogeneous, and the texture was barely changed. The main mechanism for the evolution of the structures and properties might be ascribed to the increased nucleation rate on recrystallization and the decreased dislocation density during the ECP treatment. It was reasonable to expect that the ECAP+ECP treatment would provide a promising approach for enhancing the mechanical properties of the Mg alloys.

Effect of Cryogenic Treatment on Mechanical Properties and Microstructures of 3102 Al-Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 845-848 ◽  
Author(s):  
Xian Quan Jiang ◽  
Ning Li ◽  
Hong He ◽  
Xiu Jin Zhang ◽  
Chun Chi Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperatures ◽  
Breaking Strength ◽  
Cryogenic Treatment ◽  
Al Alloy ◽  
Deep Cryogenic Treatment ◽  
Transmission Electron ◽  
Elongation To Failure ◽  
Shrinkage Force ◽  
Very Low Temperature

The mechanical properties and microstructures of different state cryogenic treatment 3102 Al-foil, such as H19，H26 or O state, were studied by tensile testing, optical metalloscopy (OM) and transmission electron microscope(TEM). The results showed that, after deep cryogenic treatment, the strength of H19 state increased and the elongation to failure decreased. In the same time, the yield strength increased and breaking strength decreases and the elongation decreased dramatically for O state, but, for H26 state, the strength and elongation increased dramatically, which correspond to the properties of this state at low temperatures. OM and TEM observation showed cryogenic treatment caused by the fibrous grains broken down and many grains with the size of 0.1~3μm These fine equiaxial grains can improve the strength and elongation of the Al-foil. On the contrary, the atomic shrinkage force slips high density dislocations into interface of the grains and forms terraces and fissure in it. That leads to the elongation decrease and the interface been broaden at very low temperature. The grain size of O state with cryogenic treatment is larger than without cryogenic treatment. As a result, the synthetic mechanical properties of H26 state improved by the way of cryogenic treatment, but the H19 state and O state should avoid use and put at low temperatures.

scholarly journals Effect of Cryogenic Treatment on Mechanical Properties of AISI 4340 and AISI 4140 Steel

2019 ◽  
Vol 38 (3) ◽  
pp. 755-766
Author(s):  
Abdul Rauf Rauf Jamali ◽  
Waseem Khan ◽  
Ali Dad Chandio ◽  
Zubai Anwer ◽  
Muhammad Hayat Jokhio
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cryogenic Treatment ◽  
Cost Effective ◽  
Micro Structure ◽  
Deep Cryogenic Treatment ◽  
Heat Treated ◽  
Aisi 4140 ◽  
The Impact ◽  
Aisi 4340

From last epoch till to date, AISI 4340 and AISI 4140 have been widely used in different engineering applications. These applications include bolt, screws, gears, drive shafts, crane shaft and piston rods for engines due to its upright mechanical properties, cost-effective and easily available in market. In present work, deep cryogenic treatment effect on the mechanical properties of AISI 4340 and AISI 4140 have been studied. Present work was carried out at laboratory scale and can be extended for mass production. Our work is simple, straight forward safe and economical. In our work, samples were heat treated in simple muffle furnace and followed by cryogenic treatment in liquid nitrogen. Before cryogenic treatment, all samples were normalized at 860°C to obtain homogenized micro structure. Samples were also compared conventionally heat treatment with quenched in oil quenchant. Experimental results showed that after cryogenic treatment with tempering treatment, one could easily increase the tensile strength, impact toughness and hardness. Advanced optical microscopy (IMM 901) and SEM (Scanning Electron Microscopy), FIT Quanta 200 methods have also been deployed to reveal and interpret the internal structure of samples. It was found from micro structure that cryogenic treated sample increases the impact strength, hardness and tensile strength as compared conventional heat treated quenching approaches.

Optimization of Strength and Ductility in Ultra-Fine 304 Stainless Steel after Equal-Channel Angular Processing

2010 ◽  
Vol 667-669 ◽  
pp. 937-942 ◽  
Author(s):  
Z.J. Zheng ◽  
Yan Gao ◽  
Y. Gui ◽  
M. Zhu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Dislocation Density ◽  
Vickers Hardness ◽  
304 Stainless Steel ◽  
Angular Pressing ◽  
Equal Channel Angular Processing ◽  
Strength And Ductility

The microstructure and mechanical properties of 304 stainless steel were investigated which was subjected to equal channel angular pressing (ECAP). Tensile strength, elongation, Vickers hardness of as-ECAPed and annealed ECAPed 304 stainless steel were systematically measured and compared and microstructure evolution during ECAP and ECAP+annealing was observed by OM and TEM. It was found that with the increasing of ECAP passes, the grain size of stainless steel was effectively refined to nanoscale, such as about 50 nm after 8 ECAP-passes. In addition, the dislocation density in ECAPed samplel increased greatly, consequently, the tensile strength and hardness of ECAPed 304 stainless steel increased and elongation decreased remarkably. After annealing at 600°C for 10 min，the ductility of ECAPed stainless steel was improved greatly while grains did not have obvious growth, and strength did not change much. The above results showed that the optimization of strength and ductility in ultra-fined 304 stainless steel can be achieved by appropriate ECAP plus annealing processes.

scholarly journals Effects of Deep Cryogenic Treatment on the Microstructure and Properties of Rolled Cu Foil

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5498
Author(s):  
Zhichao Dong ◽  
Xiangyu Fei ◽  
Benkui Gong ◽  
Xinyu Zhao ◽  
Jiwei Nie
Keyword(s):  
Mechanical Properties ◽  
Dislocation Density ◽  
High Speed ◽  
Treatment Time ◽  
Cryogenic Treatment ◽  
Wearable Electronics ◽  
Deep Cryogenic Treatment ◽  
Cu Foil ◽  
The Impact ◽  
Peak Value

The development of fifth-generation (5G) communication and wearable electronics generates higher requirements for the mechanical properties of copper foil. Higher mechanical properties and lower resistance are required for flexible copper-clad laminate and high-frequency and high-speed Cu foil. Deep cryogenic treatment (DCT), as a post-treatment method, has many advantages, such as low cost and ease of operation. However, less attention has been paid to the impact of DCT on rolled Cu foil. In this study, the effects of DCT on the microstructure and mechanical properties of rolled Cu foil were investigated. The results show that as the treatment time increased, the tensile strength and hardness first increased and then decreased, reaching a peak value of 394.06 MPa and 1.47 GPa at 12 h. The mechanical property improvement of rolled Cu foil was due to the grain refinement and the increase of dislocation density. The dislocation density of rolled Cu foil after a DCT time of 12 h was determined to have a peak value of 4.3798 × 1015 m−2. The dislocation density increased by 19% and the grain size decreased by 12% after 12 h DCT.

Effect of Li on Mechanical Properties and Electrical Conductivity of the Al–Zn–Cu–Mg Based Alloys

2021 ◽  
Vol 21 (9) ◽  
pp. 4897-4901
Author(s):  
Hyo-Sang Yoo ◽  
Yong-Ho Kim ◽  
Hyeon-Taek Son
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Tensile Strength ◽  
Spherical Particles ◽  
Al Alloy ◽  
High Angle ◽  
Average Grain Size ◽  
Strength Improvement ◽  
Li Content

In this study, changes in the microstructure, mechanical properties, and electrical conductivity of cast and extruded Al–Zn–Cu–Mg based alloys with the addition of Li (0, 0.5 and 1.0 wt.%) were investigated. The Al–Zn–Cu–Mg–xLi alloys were cast and homogenized at 570 °C for 4 hours. The billets were hot extruded into rod that were 12 mm in diameter with a reduction ratio of 38:1 at 550 °C. As the amount of Li added increased from 0 to 1.0 wt.%, the average grain size of the extruded Al alloy increased from 259.2 to 383.0 µm, and the high-angle grain boundaries (HGBs) fraction decreased from 64.0 to 52.1%. As the Li content increased from 0 to 1.0 wt.%, the elongation was not significantly different from 27.8 to 27.4% and the ultimate tensile strength (UTS) was improved from 146.7 to 160.6 MPa. As Li was added, spherical particles bonded to each other, forming an irregular particles. It is thought that these irregular particles contribute to the strength improvement.

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