scholarly journals Effects of Cold Rolling and Aging Treatment on the Properties of Cu-Be Alloy

2019 ◽  
Vol 9 (4) ◽  
pp. 4500-4503
Author(s):  
M. I. Mohamed
Keyword(s):  
Cold Rolling ◽  
Aging Time ◽  
Aging Treatment ◽  
Exothermic Peak ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Cold Rolling Reduction ◽  
Cold Rolled ◽  
Precipitated Phases ◽  
Dsc Curves

The effects of precipitated phases during aging treatment on the properties of the Cu-Be alloy have been extensively studied. In this study, the effect of cold rolling on the precipitated phases of the Cu-Be alloy compared with non-deformed alloy during isothermal and low heating rate aging of 20C/min have been investigated. Hardness changes, differential scanning calorimetry (DSC), dilatation analysis, and transmission electron microscopy (TEM) were used in this study. Hardening and contraction were strongly increased at an early aging time for the cold rolled Cu-Be alloy. In addition, the DSC curves revealed an exothermic peak from the γ΄΄ phase. This peak increased and shifted to lower aging time by increasing the cold rolling reduction. In addition, the hardness remarkably increased at lower aging temperatures for the cold rolled specimens. The contraction from the dilatation curves and the exothermic peaks shifted to lower aging temperatures in cold rolled specimens. The hardening of Cu-Be alloy is believed to be from the γ΄ phase, and the contraction and the first exothermic peak in DSC curves from γ΄΄ phase. TEM observations are in a good agreement with the above explanation and strongly revealed that γ΄΄ and γ΄ phases were highly accelerated by the effect of cold rolling

scholarly journals Microstructure and Mechanical Properties of 4Al Alumina-Forming Austenitic Steel after Cold-Rolling Deformation and Annealing

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2767 ◽  
Author(s):  
Chenchen Jiang ◽  
Qiuzhi Gao ◽  
Hailian Zhang ◽  
Ziyun Liu ◽  
Huijun Li
Keyword(s):  
Grain Size ◽  
Cold Rolling ◽  
Grain Boundaries ◽  
Austenitic Steel ◽  
Rolling Reduction ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Cold Rolling Reduction ◽  
Average Grain Size ◽  
Cold Rolled

Microstructural evolutions of the 4Al alumina-forming austenitic steel after cold rolling with different reductions from 5% to 30% and then annealing were investigated using electron backscattering diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile properties and hardness were also measured. The results show that the average grain size gradually decreases with an increase in the cold-rolling reduction. The low angle grain boundaries (LAGBs) are dominant in the cold-rolled samples, but high angle grain boundaries (HAGBs) form in the annealed samples, indicating that the grains are refined under the action of dislocations. During cold rolling, high-density dislocations are initially introduced in the samples, which contributes to a large number of dislocations remaining after annealing. With the sustaining increase in cold-rolled deformation, the samples exhibit more excellent tensile strength and hardness due to the decrease in grain size and increase in dislocation density, especially for the samples subjected to 30% cold-rolling reduction. The contribution of dislocations on yield strength is more than 60%.

Effects of Cold-Rolling Reduction on Microstructure and Mechanical Properties of Ti50Zr30Nb10Ta10 Alloy

2016 ◽  
Vol 849 ◽  
pp. 376-381
Author(s):  
Ming Long Li ◽  
Yu Jie Geng ◽  
Chen Chen ◽  
Shu Jie Pang ◽  
Tao Zhang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Plastic Strain ◽  
Cold Rolling ◽  
Reduction Ratio ◽  
High Fracture ◽  
Dendrite Structure ◽  
Microstructure And Mechanical Properties ◽  
Cold Rolling Reduction ◽  
Cold Rolled

The effects of cold-rolling with different reduction ratios of 70%-90% on the microstructure and mechanical properties of Ti50Zr30Nb10Ta10 alloy were investigated. It was found that the β-Ti phase in this alloy was stable under cold-rolling. With the increase in reduction ratio from 70% to 90%, the microstructure of the alloys evolved from deformed dendrite structure to fiber-like structure. The alloy cold-rolled with the reduction ratio of 70% exhibited optimum mechanical properties of combined high fracture strength of 1012 MPa and plastic strain of 10.1%, which are closely correlated with the dendrite structure of the alloy. It is indicated that the proper cold-rolling is an effective way to improve the mechanical properties of the titanium alloy.

Characterization of the Phase Transformations in the Shape Memory Alloy Ni-36 at.% Al

1991 ◽  
Vol 246 ◽  
Author(s):  
J.A. Horton ◽  
E.P. George ◽  
C.J. Sparks ◽  
M.Y. Kao ◽  
O.B. Cavin ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Phase Transformations ◽  
Hot Extrusion ◽  
Exothermic Peak ◽  
Nickel Aluminum ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

AbstractA survey by differential scanning calorimetry (DSC) and recovery during heating of indentations on a series of nickel-aluminum alloys showed that the Ni-36 at.% Al composition has the best potential for a recoverable shape memory effect at temperatures above 100°C. The phase transformations were studied by high temperature transmission electron microscopy (TEM) and by high temperature x-ray diffraction (HTXRD). Quenching from 1200°C resulted in a single phase, fully martensitic structure. The initial quenched-in martensites were found by both TEM and X-ray diffraction to consist of primarily a body centered tetragonal (bct) phase with some body centered orthorhombic (bco) phase present. On the first heating cycle, DSC showed an endothermic peak at 121°C and an exothermic peak at 289°C, and upon cooling a martensite exothermic peak at 115° C. Upon subsequent cycles the 289°C peak disappeared. High temperature X-ray diffraction, with a heating rate of 2°C/min, showed the expected transformation of bct phase to B2 between 100 and 200°C, however the bco phase remained intact. At 400 to 450°C the B2 phase transformed to Ni2Al and Ni5Al3. During TEM heating experiments a dislocation-free martensite transformed reversibly to B2 at temperatures less than 150°C. At higher temperatures (nearly 600°C) 1/3, 1/3, 1/3 reflections from an ω-like phase formed. Upon cooling, the 1/3, 1/3, 1/3 reflections disappeared and a more complicated martensite resulted. Boron additions suppressed intergranular fracture and, as expected, resulted in no ductility improvements. Boron additions and/or hot extrusion encouraged the formation of a superordered bct structure with 1/2, 1/2, 0 reflections.

scholarly journals Study on the Structure and Dielectric Properties of Zeolite/LDPE Nanocomposite under Thermal Aging

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2108
Author(s):  
Bai Han ◽  
Chuqi Yin ◽  
Jiaxin Chang ◽  
Yu Pang ◽  
Penghao Lv ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Aging Time ◽  
Thermal Aging ◽  
Aging Treatment ◽  
Dielectric Strength ◽  
Breakdown Field ◽  
Scanning Calorimetry ◽  
Aging Resistance ◽  
The Stability ◽  
Breakdown Field Strength

Nanodoping is an effective way to improve the dielectric properties and the aging resistance of polyethylene. Nano-zeolite has a nano-level porous structure and larger specific surface area than ordinary nano-inorganic oxide, which can be used to improve dielectric properties of low-density polyethylene (LDPE) nanocomposite. The zeolite/LDPE nanocomposites were prepared and subjected to thermal aging treatment to obtain samples with different aging time. Using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the differential scanning calorimetry (DSC) test to study the microscopic and structure characteristics, it was found that nano-zeolite doping can effectively reduce the thermal aging damage to the internal structure of the nanocomposite; carbonyl and hydroxyl decreased significantly during the thermal aging time, and the crystallinity effectively improved. Nano-zeolite doping significantly improved the morphology and strengthened the aging resistance of the nanocomposite. In the dielectric strength test, it was found that nanodoping can effectively improve the direct current (DC) and alternating current (AC) breakdown field strength and the stability after the thermal aging. The dielectric constant of nanocomposite can be reduced, and the dielectric loss had no obvious change during the aging process. Moreover, the zeolite/LDPE nanocomposite with the doping concentration of 1 wt % had the best performance, for the nano-zeolite was better dispersed.

scholarly journals Energetic Films Realized by Encapsulating Copper Azide in Silicon-Based Carbon Nanotube Arrays with Higher Electrostatic Safety

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 575 ◽  
Author(s):  
Xuwen Liu ◽  
Yan Hu ◽  
Hai Wei ◽  
Bingwen Chen ◽  
Yinghua Ye ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Alumina ◽  
Chemical Vapor ◽  
Exothermic Peak ◽  
Alumina Film ◽  
Scanning Calorimetry ◽  
Micro Electro Mechanical Systems ◽  
Transmission Electron ◽  
Anodic Oxidation Method ◽  
Silicon Based

Since copper azide (Cu(N3)2) has high electrostatic sensitivity and is difficult to be practically applied, silicon-based Cu(N3)2@carbon nanotubes (CNTs) composite energetic films with higher electrostatic safety were fabricated, which can be compatible with micro-electro mechanical systems (MEMS). First, a silicon-based porous alumina film was prepared by a modified two-step anodic oxidation method. Next, CNTs were grown in pores of the silicon-based porous alumina film by chemical vapor deposition. Then, copper nanoparticles were deposited in CNTs by electrochemical deposition and oxidized to Cu(N3)2 by gaseous hydrogen azide. The morphology and composition of the prepared silicon-based Cu(N3)2@CNTs energetic films were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. The electrostatic sensitivity of the composite energetic film was tested by the Bruceton method. The thermal decomposition kinetics of the composite energetic films were studied by differential scanning calorimetry (DSC). The results show that the exothermic peak of the silicon-based Cu(N3)2@CNTs composite energetic film is at the temperature of 210.95 °C, its electrostatic sensitivity is significantly less than that of Cu(N3)2 and its 50% ignition energy is about 4.0 mJ. The energetic film shows good electric explosion characteristics and is successfully ignited by laser.

Mechanical, Thermal and Electrical Characteristics of Conventionally Cast and Cold-Rolled 5754-Sc-Zr Aluminium Alloy

2019 ◽  
Vol 22 ◽  
pp. 55-64
Author(s):  
Martin Vlach ◽  
Veronika Kodetová ◽  
Hana Kudrnová ◽  
Michal Leibner ◽  
Marián Vlček ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Electron Backscatter Diffraction ◽  
Residual Resistivity ◽  
Precipitation Process ◽  
Residual Resistivity Ratio ◽  
Scanning Calorimetry ◽  
Resistivity Ratio ◽  
Cold Rolled ◽  
Initial Difference ◽  
C 30

The effect of cold-rolling on mechanical, thermal, and electrical properties as well as microstructure behaviour of the Al-2.93wt.%Mg-0.34wt.%Mn-0.33wt.%Si-0.22wt.%Fe-0.19wt.%Cr-0.24wt.%Sc-0.06wt.%Zr was studied. The material was investigated during step-by-step isochronal annealing in a temperature range from room temperature up to 540 °C and during isothermal annealing at 200, 450 and 550 °C. Precipitation reactions were studied by electrical resistometry, conductivity, (micro) hardness measurements and differential scanning calorimetry. The hardening effect appears due to the additional precipitation of the Al3Sc and/or Al3(Sc,Zr) particles. The distinct changes in residual resistivity ratio above ~ 330 °C are probably caused by precipitation of the Mn (,Fe,Cr)-containing particles. This precipitation process is highly influenced by cold rolling but it has a negligible effect on hardness. The apparent activation energy values for additional formation of the Al3Sc and/or Al3(Sc,Zr) particles were determined. The kinetics of the Al3(Sc,Zr)-phase precipitation seems to be independent of Mn-and Mg-addition in the studied alloys. A partial recrystallization of the cold-rolled alloy was registered by electron backscatter diffraction after annealing at 550 °C. The initial difference in microhardness introduced by cold rolling is almost removed after annealing at 550 °C/30 min.

Effect of Cold-Rolling Reduction on Recrystallized Annealing Microstructure and Texture of Titanium Stabilized Interstitial Free Steel

2012 ◽  
Vol 581-582 ◽  
pp. 1010-1013
Author(s):  
Gong Ting Zhang ◽  
Zhi Wang Zheng ◽  
Min Li Wang
Keyword(s):  
Cold Rolling ◽  
Salt Bath ◽  
Rolling Reduction ◽  
Interstitial Free ◽  
Texture Measurement ◽  
Cold Rolling Reduction ◽  
Interstitial Free Steel ◽  
Cold Rolled ◽  
Evolution Of Microstructure ◽  
Annealing Microstructure

Cold rolling and salt bath annealing simulation were conducted to study the evolution of microstructure and textures of a commercially produced Titanium stabilized interstitial free steel by means of optical microscopy and X-ray texture measurement. The results show that all of the as cold-rolled specimens are completely recrystallized after annealing. As the cold-rolling reduction increases, the recystallized ferrite grains are refined, The intensities of the stable {114} and {223} components remain strong after recrystallization. The orientation intensity of the {111} and {111} also increases accordingly. As the cold-rolling reduction increases to 90%, the intensity of {111} tend to be higher than that of {111}.

Cyclic Behavior of Reversion-Treated Structures after Different Cold Rolling Reductions in an AISI 301LN Stainless Steel

2018 ◽  
Vol 786 ◽  
pp. 52-56
Author(s):  
Antti Järvenpää ◽  
Matias Jaskari ◽  
Pentti L. Karjalainen
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Cold Rolling ◽  
Stress Amplitude ◽  
Cyclic Hardening ◽  
Coarse Grained ◽  
Cyclic Behavior ◽  
Size Refinement ◽  
Cold Rolling Reduction ◽  
Cold Rolled

Lower cold rolling reductions before reversion annealing for the grain size refinement are desired in industrial practice. This study demonstrates the effect of a low (32%) cold rolling reduction on cyclic behavior of a partially reversed (750 °C for 0.1s) structure in a 17Cr-7Ni-N type 301LN austenitic stainless steel and compares it with those of a 63% cold rolled and annealed and with a conventional coarse-grained structure. Stress amplitude and the amount of deformation-induced martensite formed under cyclic loading at the 0.6% total strain amplitude were recorded. The results showed that the partially reversed structure after the 32% cold rolling reduction exhibits the similar cyclic stress amplitude level and slight cyclic hardening as the 63% cold-rolled counterpart does. Even though the grain size refinement remains less effective at the lower reduction, the microstructure consists of higher fractions of strong retained cold-deformed austenite and martensite phases which increase the flow resistance. However, the coarse-grained structure exhibits a much lower initial stress amplitude and much more pronounced cyclic hardening. The susceptibility of austenite to transform deformation-induced martensite is practically similar among these three structures. However, the cyclic hardening is a caused by the formation of deformation-induced martensite, and the difference in the degree of cyclic hardening results from the big difference in the strength of the austenite between the partially reversed fine-grained and coarse-grained structures.

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