Thoughts on High Performance Superalloy Design and Microstructural Characteristics of a Newly Designed Ni-Cr-Co-W Superalloy Applied above 850°C

2019 ◽  
Vol 944 ◽  
pp. 13-24
Author(s):  
Xue Mei Xiang ◽  
He Jiang ◽  
Jian Xin Dong ◽  
Zhi Hao Yao
Keyword(s):  
High Performance ◽  
Aircraft Engine ◽  
Optical Microscope ◽  
Turbine Disk ◽  
Incipient Melting ◽  
Scanning Calorimetry ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Disk Material ◽  
Cast Condition

With the development of aircraft engine, higher requirement was put forward on turbine disk materials. In the present work, new thoughts on improving high temperature properties of superalloys have been proposed and a newly developed candidate turbine disk material for 850°C-900°C application with a composition of Ni-Co-Cr-W superalloy has been investigated. The results show that W is beneficial for mechanical properties. Microstructural characteristics and hot deformation of this new alloy were studied by optical microscope (OM), field emission scanning electric microscope (FESEM) and energy dispersive X-ray spectrometer (EDX) and differential scanning calorimetry (DSC). The results show that the main precipitates in the as-cast condition are γ’ phase, primary MC carbides and eutectic phase. The incipient melting temperature, γ’ solvus and MC solvus are 1312°C, 1220°C and 1356°C respectively. Cracks are observed in the tested samples after hot deformed at 1160°C to 1220°C with 30% strain. They initiated at the surface of the samples and propagated along the grain boundaries and also initiated at the interface of carbides and matrix.

Influence of aging on microstructure and hardness of lead-free solder alloys

2020 ◽  
Vol 33 (1) ◽  
pp. 57-64
Author(s):  
Carina Morando ◽  
Osvaldo Fornaro
Keyword(s):  
Isothermal Aging ◽  
Treatment Time ◽  
Cast Alloy ◽  
Scanning Calorimetry ◽  
Content Type ◽  
X Ray ◽  
Different Temperatures ◽  
Free Solder ◽  
Cast Condition ◽  
Dsc Calorimetry

Purpose The purpose of this paper is to carry out a study of the evolution of the microstructure and the microhardness of Sn-Cu-Ag alloys from as-cast condition and under artificial isothermal aging at different temperatures (100ºC and 180ºC) for a treatment time up to 500 h. A comparison with Sn-37% Pb eutectic solder samples was also made. Design/methodology/approach Sn-3.5%Ag, Sn-0.7%Cu and Sn-3.5%Ag-0.9%Cu were poured in two different cooling rate conditions and then aged at 100ºC (373ºK) and 180 °C (453ºK) during 500 h. Microstructural changes were observed by optical microscopy, scanning electron micrograph and energy dispersive X-ray microanalysis. Differential scanning calorimetry technique (DSC) was also used to confirm the obtained results. Findings A decrease up to 20% in microhardness respect to the value of the as-cast alloy was observed for both aging temperatures. These changes can be explained considering the coarsening and recrystallization of Sn dendrites present in the microstructures of all the systems studied. Originality/value There is no evidence of dissolution or precipitation of new phases in the range of studied temperatures that could be detected by DSC calorimetry technique. The acting mechanisms must be the result of coarsening of Sn dendrites and the residual stresses relaxation during the first stages of the isothermal aging.

When dendrimers are not better – rational design of nanolayers for high-performance organic electronic devices

Nanoscale ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 4463-4470 ◽  
Author(s):  
Maxim A. Shcherbina ◽  
Oleg V. Borshchev ◽  
Alexandra P. Pleshkova ◽  
Sergei A. Ponomarenko ◽  
Sergei N. Chvalun
Keyword(s):  
High Performance ◽  
Rational Design ◽  
Electronic Devices ◽  
Carbosilane Dendrimers ◽  
Scanning Calorimetry ◽  
Organic Electronic Devices ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force

Several generations of carbosilane dendrimers with quaterthiophene end groups were studied by X-ray scattering, differential scanning calorimetry, polarizing optical and atomic force microscopy and molecular modelling.

Chiral Liquid Crystalline Polymers Containing Isosorbide Groups

2013 ◽  
Vol 781-784 ◽  
pp. 403-406
Author(s):  
Mei Tian ◽  
Zhi Xin Xu ◽  
Li Gao ◽  
Dan Shu Yao ◽  
Xiao Zhi He ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Main Chain ◽  
Liquid Crystalline Polymers ◽  
Optical Microscope ◽  
Liquid Crystal Polymers ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystalline Polymers

A series of new main-chain liquid-crystal polymers (LCPs) were prepared from sebacoyl chloride (SD) and various amount of 4, 4-Dihydroxy-2, 2-dimethyl Benzalazine (DDBA) and isosorbide (ISO). The liquid crystal (LC) properties were investigated by polarized optical microscope (POM), differential scanning calorimetry (DSC) and X-ray diffraction measurements. P1 exhibited a typical nematic thread texture, which contains no ISO. P2-P7 are Sc* and N LCPs, which exhibited broken fan-shaped texture and droplet texture. The introduction of chiral units into the polymers led to a change of mesomorphase, as compared with P1.

Crystal Polymorphs and Multiple Crystallization Pathways of Highly Pressurized 1-Ethyl-3-Methylimidazolium Nitrate

2019 ◽  
Vol 72 (2) ◽  
pp. 87 ◽  
Author(s):  
Hiroshi Abe ◽  
Takahiro Takekiyo ◽  
Yukihiro Yoshimura ◽  
Nozomu Hamaya ◽  
Shinichiro Ozawa
Keyword(s):  
Differential Scanning Calorimetry ◽  
High Pressure ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Low Temperature Crystallization ◽  
Temperature Crystallization

Crystal polymorphs and multiple crystallization pathways of a room-temperature ionic liquid (RTIL) were observed only under high pressure (HP). The RTIL was 1-ethyl-3-methylimidazolium nitrate, [C2mim][NO3]. The HP-crystal polymorphs were related to conformations of the C2mim+ cation, and the HP-crystal pathways determined by the presence or absence of the planar′ (P′) conformation of the C2mim+ cation were switched at the bifurcation pressure (PB). Above PB, modulated crystal structures derived from the HP-inherent P′ conformer. Simultaneous X-ray diffraction and differential scanning calorimetry measurements, accompanied by optical microscope observations, confirmed the normal low-temperature crystallization of [C2mim][NO3] under ambient pressure.

Reactive Synthesis of TiAl/Ti5Si3 In Situ Composites

2011 ◽  
Vol 217-218 ◽  
pp. 684-687
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Shao Dan Li
Keyword(s):  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Microstructural Characteristics ◽  
Powder Mixtures ◽  
X Ray ◽  
Reactive Synthesis ◽  
In Situ Composite ◽  
The Matrix ◽  
A Minor

Full dense and highly pure TiAl/Ti5Si3 in situ composite was successfully synthesized by reactive synthesis from the powder mixtures of Ti, Al and Si. The reaction process was investigated in detail by the X-ray diffraction analysis (XRD) and differential scanning calorimetry (DSC). The microstructural characteristics of the TiAl/Ti5Si3 in situ composite were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the as fabricated composite possesses three phases, namely, TiAl, Ti3Al and Ti5Si3. The matrix phases are mainly equiaxed TiAl with a minor lamellar Ti3Al phase. Ti5Si3 particles with size less than 1 μm are distributed uniformly in matrix grains as a reinforcing phase.

scholarly journals Pharmaceutical Salts of Enrofloxacin with Organic Acids

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 646
Author(s):  
Hong Pang ◽  
Yu-Bin Sun ◽  
Jun-Wen Zhou ◽  
Meng-Juan Xie ◽  
Hao Lin ◽  
...  
Keyword(s):  
High Performance ◽  
Water Solubility ◽  
Antibacterial Drug ◽  
Mixed Solution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Organic Salts ◽  
X Ray ◽  
Poorly Soluble ◽  
Pharmaceutical Properties

Enrofloxacin is a poorly soluble antibacterial drug of the fluoroquinolones class used in veterinary medicine. The main purpose of this work was to investigate the structural and pharmaceutical properties of new enrofloxacin salts. Enrofloxacin anhydrate and its organic salts with tartaric acid, nicotinic acid and suberic acid formed as pure crystalline anhydrous solids. All the crystals were grown from a mixed solution by slow evaporation at room temperature. These products were then characterized by field-emission scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry. Further, X-ray single crystal diffraction analysis was used to study the crystal structure. The intermolecular interactions and packing arrangements in the crystal structures were studied, and the solubility of these salts in water was determined using high-performance liquid chromatography. The results show that the new salts of enrofloxacin developed in this study exhibited excellent water solubility.

An investigation on the microstructure and defects in the mechanically milled Cu and Fe powders

2014 ◽  
Vol 30 (1) ◽  
pp. 14-24
Author(s):  
M. Mojtahedi ◽  
M. Goodarzi ◽  
M. R. Aboutalebi ◽  
V. Soleimanian
Keyword(s):  
Three Dimensional ◽  
Geometrical Approach ◽  
Stored Energy ◽  
Line Broadening ◽  
Scanning Calorimetry ◽  
Microstructural Characteristics ◽  
X Ray ◽  
X Ray Crystallography ◽  
Geometrical Modelling ◽  
Released Energy

The microstructural characteristics of mechanically milled (MM) iron (Fe) and copper (Cu) powders are investigated by means of various X-ray crystallography analysis methods. The conventional Williamson–Hall and Warren–Averbach methods are used besides the modified Williamson–Hall, the modified Warren–Averbach, and the Variance approaches, in proper cases. Afterward, the obtained crystallite size and dislocation density are used to calculate the stored energy in the nanostructured powders. For this aim, a new geometrical approach is developed which can consider three-dimensional crystallites and the thickness of boundaries between them. Moreover, the released energy during annealing of MM Cu and Fe powders is measured using differential scanning calorimetry. The results of line broadening analysis and geometrical modelling are combined to the calorimetry of a room temperature aged Cu powder. In this way, the thickness of grain boundary in the nanostructured Cu is calculated to be 1.6 nm.

Synthesis and Characterization of Thermoplastic Biomaterial Based on Acylated Chitosan Oligosaccharide

2011 ◽  
Vol 117-119 ◽  
pp. 1433-1436 ◽  
Author(s):  
Feng Hong Li ◽  
Yong Sun ◽  
San Xi Li ◽  
Shao Jun Ma
Keyword(s):  
Optical Microscope ◽  
Chitosan Oligosaccharide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
X Ray ◽  
Chemical Structures ◽  
Chitosan Oligosaccharides ◽  
Diffraction Peaks

A series of acylated chitosan oligosaccharides (LCSOs) were synthesized by reacting chitosan oligosaccharide (CSO) with lauroyl chloride in methane sulfonic acid. The chemical structures of LCSOs were characterized by Fourier transform infrared. Differential scanning calorimetry (DSC) showed that LCSOs had two phase transitions during heating. Thermoplastic chitosan oligosaccharide (LCSO-4) has distinct melting temperature (Tm) at 64 °C and 110°C. X-ray diffraction (XRD) analyses indicated that the crystal structure of CSO was changed through acylation and had created new crystal domains of lauroyl side chains. New strong diffraction peaks were observed around 2θ values of 20.0°, 21.5° and 26.3° for thermoplastic acylated chitosan oligosaccharide (LCSO-4). The melting and crystallization properties of thermoplastic acylated chitosan oligosaccharide were observed by polarized optical microscope (POM).

Syntheses and Characterization of Chitosan Oligosaccharide-Graft-Polycaprolactone Copolymer I Thermal and Spherulite Morphology Studies

2011 ◽  
Vol 183-185 ◽  
pp. 155-160 ◽  
Author(s):  
Feng Hong Li ◽  
San Xi Li ◽  
Tao Jiang ◽  
Yong Sun
Keyword(s):  
Ring Opening ◽  
Optical Microscope ◽  
Chitosan Oligosaccharide ◽  
Dsc Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Spherulite Morphology ◽  
Thermal Stable

The thermoplastic graft copolymers of chitosan oligosaccharide (PHCSO-g-PCL) were successfully synthesized via ring-opening polymerization (ROP) of ε-caprolactone (CL) through an amino group protection route using phthaloyl chitosan oligosaccharide (PHCSO) as intermediate. The graft reaction was carried out in Pyridine at 120 °C with a chitosan oligosaccharide (CSO) initiator and a tin 2-ethylhexanoate (Sn (Oct)2) catalyst. The prepared copolymer was characterized by FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray diffraction (WAXD). DSC analysis of PHCSO-g-PCL showed higher melting point at 54.8 °C than linear PCL. The TGA analysis showed that PHCSO-g-PCL was more thermal stable than original CSO. The banded spherulite structure of PHCSO-g-PCL and the growth of spherulite were observed by polarized optical microscope (POM); this was further proven by WAXD results.

scholarly journals Production of Nanocellulose by Enzymatic Treatment for Application in Polymer Composites

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2124
Author(s):  
Daria Zielińska ◽  
Kinga Szentner ◽  
Agnieszka Waśkiewicz ◽  
Sławomir Borysiak
Keyword(s):  
Polymer Composites ◽  
High Performance ◽  
Structural Parameters ◽  
Supermolecular Structure ◽  
Strength Properties ◽  
Cellulolytic Enzymes ◽  
Enzymatic Reactions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

In the last few years, the scientific community around the world has devoted a lot of attention to the search for the best methods of obtaining nanocellulose. In this work, nanocellulose was obtained in enzymatic reactions with strictly defined dispersion and structural parameters in order to use it as a filler for polymers. The controlled enzymatic hydrolysis of the polysaccharide was carried out in the presence of cellulolytic enzymes from microscopic fungi—Trichoderma reesei and Aspergillus sp. It has been shown that the efficiency of bioconversion of cellulose material depends on the type of enzymes used. The use of a complex of cellulases obtained from a fungus of the genus Trichoderma turned out to be an effective method of obtaining cellulose of nanometric dimensions with a very low polydispersity. The effect of cellulose enzymatic reactions was assessed using the technique of high-performance liquid chromatography coupled with a refractometric detector, X-ray diffraction, dynamic light scattering and Fourier transform infrared spectroscopy. In the second stage, polypropylene composites with nanometric cellulose were obtained by extrusion and injection. It was found by means of X-ray diffraction, hot stage optical microscopy and differential scanning calorimetry that nanocellulose had a significant effect on the supermolecular structure, nucleation activity and the course of phase transitions of the obtained polymer nanocomposites. Moreover, the obtained nanocomposites are characterized by very good strength properties. This paper describes for the first time that the obtained cellulose nanofillers with defined parameters can be used for the production of polymer composites with a strictly defined polymorphic structure, which in turn may influence future decision making about obtaining materials with controllable properties, e.g., high flexibility, enabling the thermoforming process of packaging.

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