The effects of combined cyclic close die forging and aging process on microstructure and mechanical properties of AA7075

2020 ◽  
Vol 234 (9) ◽  
pp. 1242-1251
Author(s):  
MA Moazam ◽  
M Honarpisheh
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Crack Formation ◽  
Experimental Tests ◽  
Ultimate Tensile Stress ◽  
X Ray ◽  
Die Forging ◽  
Transmission Electron ◽  
Processed Sample

It is well known that applying severe plastic deformation methods on the precipitation hardenable aluminum alloys at room temperature is very difficult because of crack formation and segmentation of the specimen during the processes. In this study, several procedures were experimentally examined for performing the cyclic close die forging (CCDF) and improving the mechanical properties of AA7075. The experimental tests revealed that supersaturated solid solution of AA7075 after water quenching is formable for only about 5 min and performing the CCDF process in this limited time is possible. Optical and scanning electron microscopy and transmission electron microscopy were used to study the microstructure of the processed samples. It was observed that by applying two passes of CCDF, the grain size of the material reduced from 30 µm to about 200–300 nm. In addition, the X-ray diffractometer results demonstrated that Guinier–Preston zone picks of the processed samples are very weak and the equilibrium η-phase does not exist in none of the suggested procedures. Furthermore, it was found that by combining CCDF and aging processes according to the proposed procedures, the mechanical properties of the processed AA7075 were improved when compared with the AA7075-T6. To put it more clearly, micro-hardness, yield strength and ultimate tensile stress of the processed sample were improved as much as 38.6%, 25% and 23%, respectively.

Helium Implantation Damage in SiC

2005 ◽  
Vol 108-109 ◽  
pp. 709-712
Author(s):  
Stephanie Leclerc ◽  
Marie France Beaufort ◽  
Valerie Audurier ◽  
Alain Déclemy ◽  
Jean François Barbot
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Helium Ions ◽  
X Ray ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Helium Implantation

Single crystals SiC were implanted with 50 keV helium ions at room temperature and fluences in the range 1x1016 -1x1017 cm-2. The helium implantation induced swelling was studied through the measurement of the step height. The damage was studied by using X-ray diffraction measurements and the transmission electron microscopy observations. Degradation of mechanical properties is found after helium implantation.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

A Facile Fynthesis of ZnS Nanostructures via Liquid-Solid Reactions

2014 ◽  
Vol 979 ◽  
pp. 184-187
Author(s):  
Weerachon Phoohinkong ◽  
Thitinat Sukonket ◽  
Udomsak Kitthawee
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Inorganic Salts ◽  
Chloride Salt ◽  
X Ray ◽  
Commercial Grade ◽  
Transmission Electron ◽  
Salt Addition ◽  
20 Nm ◽  
Scanning Electron

Zinc sulfide (ZnS) nanostructures are important materials for many technologies such as sensors, infrared windows, transistors, LED displays, and solar cells. However, many methods of synthesizing ZnS nanostructures are complex and require expensive equipment. In this study, a liquid-solid chemical reaction without surfactant was used to synthesize ZnS at room temperature. In addition, commercial grade zinc oxide (ZnO) particles were used as a precursor. The effect of the addition of acids and inorganic salts were investigated. The products were characterized by field emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The results show that the nanoparticles of ZnS were obtained in hydrochloric acid and acetic acid addition. The diameters were in the range of 10 to 20 nm and 50 to 100 nm, respectively. In the case of a sodium chloride salt addition, a ZnS structure was obtained with a particle size of approximately 5 nm and a flake-like morphology.

New method for the production of bulk amorphous materials of Nd–Fe–B alloys

2005 ◽  
Vol 20 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Tetsuji Saito ◽  
Hiroyuku Takeishi ◽  
Noboru Nakayama
Keyword(s):  
Electron Microscopy ◽  
Amorphous Materials ◽  
Room Temperature ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons

We report a new compression shearing method for the production of bulk amorphous materials. In this study, amorphous Nd–Fe–B melt-spun ribbons were successfully consolidated into bulk form at room temperature by the compression shearing method. X-ray diffraction and transmission electron microscopy studies revealed that the amorphous structure was well maintained in the bulk materials. The resultant bulk materials exhibited the same magnetic properties as the original amorphous Nd–Fe–B materials.

Room Temperature Self-Annealing of Electroplated and Sputtered Copper Films

1999 ◽  
Vol 562 ◽  
Author(s):  
Michelle Chen ◽  
Suraj Rengarajan ◽  
Peter Hey ◽  
Yezdi Dordi ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Copper Film ◽  
Copper Films ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electroplated Copper ◽  
Effect Of Copper

ABSTRACTSelf-annealing properties of electroplated and sputtered copper films at room temperature were investigated in this study, in particular, the effect of copper film thickness, electrolyte systems used, as well as their level of organic additives for electroplating. Real-time grain growth was observed by transmission electron microscopy. Sheet resistance and X-ray diffraction measurements further confirmed the recrystallization of the electroplated copper film with time. The recrystallization of electroplated films was then compared with that of sputtered copper films.

scholarly journals Hyperfine interaction and some thermomagnetic properties of amorphous and partially crystallized Fe70−xMxMo5Cr4Nb6B15 (M = Co or Ni, x = 0 or 10) alloys

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 121-126
Author(s):  
Jakub Rzącki ◽  
Jan Świerczek ◽  
Mariusz Hasiak ◽  
Jacek Olszewski ◽  
Józef Zbroszczyk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hyperfine Interaction ◽  
Magnetic Structure ◽  
Curie Point ◽  
Room Temperature ◽  
Ferromagnetic Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Thermomagnetic Properties

Abstract As revealed by Mössbauer spectroscopy, replacement of 10 at.% of iron in the amorphous Fe70Mo5Cr4Nb6B15 alloy by cobalt or nickel has no effect on the magnetic structure in the vicinity of room temperature, although the Curie point moves from 190 K towards ambient one. In the early stages of crystallization, the paramagnetic crystalline Cr12Fe36Mo10 phase appears before α-Fe or α-FeCo are formed, as is confirmed by X-ray diffractometry and transmission electron microscopy. Creation of the crystalline Cr12Fe36Mo10 phase is accompanied by the amorphous ferromagnetic phase formation at the expense of amorphous paramagnetic one.

scholarly journals A Novel X-Ray Radiation Sensor Based on Networked SnO2 Nanowires

2019 ◽  
Vol 9 (22) ◽  
pp. 4878 ◽  
Author(s):  
Jae-Hun Kim ◽  
Ali Mirzaei ◽  
Hyoun Woo Kim ◽  
Hong Joo Kim ◽  
Phan Quoc Vuong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Low Cost ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Radiation Sensor ◽  
Sno2 Nanowires ◽  
Radiation Sensors

X-Ray radiation sensors that work at room temperature are in demand. In this study, a novel, low-cost real-time X-ray radiation sensor based on SnO2 nanowires (NWs) was designed and tested. Networked SnO2 NWs were produced via the vapor–liquid–solid technique. X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM) analyses were used to explore the crystallinity and morphology of synthesized SnO2 NWs. The fabricated sensor was exposed to X-rays (80 kV, 0.0–2.00 mA) and the leakage current variations were recorded at room temperature. The SnO2 NWs sensor showed a high and relatively linear response with respect to the X-ray intensity. The X-ray sensing results show the potential of networked SnO2 NWs as novel X-ray sensors.

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Analytical Techniques ◽  
Heating Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

Synthesis of Silicon Carbide Nanoparticles from Carbon Nanotubes

2012 ◽  
Vol 602-604 ◽  
pp. 183-186 ◽  
Author(s):  
Jing Liu ◽  
Rong Wu ◽  
Jin Li ◽  
Yan Fei Sun ◽  
Ji Kang Jian
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Room Temperature ◽  
Sic Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Cubic Silicon Carbide ◽  
Scanning Electron

In this paper, we report the synthesis of cubic silicon carbide (3C-SiC) nanoparticles by direction reaction of silicon powders and carbon nanotubes. The as-prepared SiC nanoparticles were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and Raman scattering at room temperature. The possible growth mechanism is proposed.

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