Investigation of Structure and Properties of the Al–Y–Ni–Co–Cu Metallic Glasses

2002 ◽  
Vol 17 (5) ◽  
pp. 1014-1018 ◽  
Author(s):  
Dmitri V. Louzguine ◽  
Akihisa Inoue

The present paper reports the effect of partial replacement of Ni by Cu in the Al85Y8Ni5Co2 alloy. The studied alloys were produced by rapid solidification. Glass-formation, crystallization behavior, and stability of the supercooled liquid were studied by x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Partial replacement of Ni by Cu in the Al85Y8Ni5Co2 metallic glass caused formation of the nanoscale α–Al particles and resulted in a decrease in the crystallization temperature and disappearance of the supercooled liquid.

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2775-2779
Author(s):  
X. F. ZHANG ◽  
X. Q. HUANG ◽  
R. W. PENG ◽  
G. Q. WANG ◽  
S. Y. ZHANG

The amorphous alloys of Co 50 Fe 20 Cu 2 V 8 B 20 are successfully obtained by using the mechanical alloying technique. The sample is analyzed by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. The DSC result of the powder sample milled for 120 h shows a complete amorphous phase and a wide supercooled liquid region (Tx - Tg ≃ 80 K ).


2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.


2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.


1991 ◽  
Vol 230 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.


2004 ◽  
Vol 19 (12) ◽  
pp. 3586-3591 ◽  
Author(s):  
Jiyang Chen ◽  
Ying Shi ◽  
Jianlin Shi

Nano-sized (Y,Gd)2O3:Eu powders were synthesized by a novel co-precipitation processing in which a mixture of ammonium hydroxide and ammonium hydrogen carbonate was adopted as a complex precipitant. Evolution behaviors of precursors during calcinations were studied by means of thermogravimetry-differential scanning calorimetry-mass spectrum, Fourier transform infrared, x-ray diffraction, scanning electron microscopy, and transmission electron microscopy in detail. Nano-sized (Y,Gd)2O3:Eu powder as prepared possessed a primary grain size of about 30 nm and specific surface area of 38 m2/g after being calcined at 850 °C for 2 h, showing much finer grains and less agglomeration. The as prepared nanopowder shows intense luminescence at 611nm under x-ray or ultraviolet excitation. Transparent (Y,Gd)2O3:Eu ceramics can also be fabricated using this high sinterable nanopowder.


2009 ◽  
Vol 24 (1) ◽  
pp. 39-49 ◽  
Author(s):  
J. Zhang ◽  
B. Liu ◽  
J.Y. Wang ◽  
Y.C. Zhou

Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and x-ray diffraction (XRD) investigations were conducted on the hot-pressed Ti2SnC bulk ceramic. Microstructure features of bulk Ti2SnC ceramic were characterized by using TEM, and a needle-shaped β-Sn precipitation was observed inside Ti2SnC grains with the orientation relationship: (0001) Ti2SnC // (200) Sn and Ti2SnC // [001] Sn. With the combination of DSC and XRD analyses, the precipitation of metallic Sn was demonstrated to be a thermal stress-induced process during the cooling procedure. The reheating temperature, even as low as 400 °C, could trigger the precipitation of Sn from Ti2SnC, which indicated the low-temperature instability of Ti2SnC. A substoichiometry Ti2SnxC formed after depletion of Sn from ternary Ti2SnC phase. Under electron beam irradiation, metallic Sn was observed diffusing back into Ti2SnxC. Furthermore, a new Ti7SnC6 phase with the lattice constants of a = 0.32 and c = 4.1 nm was identified and added in the Ti-Sn-C ternary system.


2014 ◽  
Vol 21 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Daniela Nunes ◽  
Lídia Santos ◽  
Paulo Duarte ◽  
Ana Pimentel ◽  
Joana V. Pinto ◽  
...  

AbstractThe present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.


1992 ◽  
Vol 7 (4) ◽  
pp. 888-893 ◽  
Author(s):  
M. Sherif El-Eskandarany ◽  
K. Sumiyama ◽  
K. Aoki ◽  
K. Suzuki

Nonequilibrium titanium-nitride alloy powders have been fabricated by a high energetic ball mill under nitrogen gas flow at room temperature and characterized by means of x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. Initial hcp titanium is completely transformed to nonequilibrium-fcc Ti–N after 720 ks of the milling time. The fcc Ti–N phase is stable at relatively low temperature and transforms at 855 K to Ti2N and δ phases. At the final stage of milling, the particle- and grain-sizes of alloy powders are 1 mm and 5 nm, respectively, and the lattice parameter is 0.419 nm.


2010 ◽  
Vol 44-47 ◽  
pp. 2373-2376
Author(s):  
Hui Qin Zhang ◽  
Li Yan Zhang

Polyacrylamide (PAM)/silver (Ag) nanoparticle composites were prepared via heat treatment of a mixture solution of silver nitrate (AgNO3) and PAM. The resultant composites were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). XRD results showed that pure phase Ag was obtained in the prepared nanocomposites. TEM results showed that the Ag particles were in sphere shape with 8-25nm diameter in the as-prepared nanocomposites. DSC results showed that the glass transition temperature of the nanocomposites was enhanced by the incorporation of Ag.


Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Bwalya A. Witika ◽  
Vincent J. Smith ◽  
Roderick B. Walker

Lamivudine (3TC) and zidovudine (AZT) are antiretroviral agents used to manage HIV/AIDS infection. A wet media milling top-down approach was used to develop and produce nano co-crystals of 3TC and AZT. Micro co-crystals were prepared by solvent evaporation and subsequently milled in the presence of two surfactants, viz., sodium lauryl sulfate (SLS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000). Optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) to establish and identify parameters that may affect the manufacturing of nano co-crystals. The impact of SLS and TPGS 1000 concentration, milling time, and number of units of milling medium on the manufacturing of nano co-crystals, was investigated. The critical quality attributes (CQA) monitored were particle size (PS), Zeta potential (ZP), and polydispersity index (PDI). Powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, transmission electron microscopy, energy dispersive X-ray spectroscopy scanning electron microscopy, and cytotoxicity assays were used for additional characterization of the optimised nano co-crystal. The mean PS, PDI, and ZP of the optimised top-down nanocrystal were 271.0 ± 92.0 nm, 0.467 ± 0.073, and −41.9 ± 3.94 mV, respectively. In conclusion, a simple, inexpensive, rapid, and precise method of nano co-crystal manufacturing was developed, validated, and optimised using DoE and RSM, and the final product exhibited the target CQA.


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