The thermal fission-induced crystalline-to-amorphous transformation in U6Fe

1988 ◽  
Vol 3 (3) ◽  
pp. 453-460 ◽  
Author(s):  
Don M. Parkin ◽  
Reed O. Elliott
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
Amorphous Material ◽  
Nucleation And Growth ◽  
Local Defect ◽  
Scanning Calorimetry ◽  
Dose Dependent ◽  
Limited Process ◽  
Total Resistivity ◽  
Crystalline Matrix

The crystalline-to-amorphous transformation in U6Fe produced by thermal fission fragment damage was studied using resistivity and differential scanning calorimetry. The results are described in terms of a model of radiation-produced defect buildup in the crystalline matrix followed by transformation of small regions to an amorphous phase when a critical local defect concentration is reached. This can occur directly in a single cascade or from cascade overlap. The total resistivity is modeled assuming an inhomogeneous media consisting of a crystalline matrix containing a dose-dependent concentration of defects and amorphous zones. The crystallization behavior is initially, starting at Tc = 388 K, a kinetically limited process of shrinkage of amorphous zones that gradually transforms to nucleation and growth in fully amorphous material at Tc = 555 K.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

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.

Crystallization Behavior of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2012 ◽  
Vol 184-185 ◽  
pp. 932-935
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
Crystallization Process ◽  
In Situ Polymerization ◽  
Nucleating Agent ◽  
Lower Content ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Montmorillonite Nanocomposites

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The crystallization behavior of PE/MMT nanocomposites at different MMT concentrations (from 0.1 to 1.2 wt %) were investigated by differential scanning calorimetry (DSC). The equilibrium melting points increase by the addition of MMT. The crystallization rates of PE/MMT nanocomposites are faster than those of pure PE. The addition of MMT facilitated the crystallization of PE, with the MMT functioning as a heterogeneous nucleating agent at lower content; at higher concentrations, however, the physical hindrance of the MMT layers to the motion of PE chains retarded the crystallization process.

Engineering the crystallization behavior of an organic compound mixed with polymers using hidden liquid phase domains

2020 ◽  
Vol 5 (1) ◽  
pp. 177-185
Author(s):  
Gagan N. Kangovi ◽  
Sangwoo Lee
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Phase ◽  
Organic Compound ◽  
Organic Compounds ◽  
Crystallization Behavior ◽  
Scanning Calorimetry ◽  
Poly Ethylene

The crystallization behavior of pyrene mixed with polystyrene, poly(ethylene-alt-propylene) or poly(2-vinylpyridine) is investigated using the differential scanning calorimetry (DSC) technique to understand the effects of polymers on the crystallization of organic compounds.

Reactions in Metal-Metalloid Multilayers

1993 ◽  
Vol 311 ◽  
Author(s):  
Robert Sinclair ◽  
Toyohiko J. Konno
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Reactive Systems ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Scanning Calorimetry ◽  
Compound Formation ◽  
Transmission Electron

ABSTRACTWe have studied the reactions at metal-metalloid interfaces using high resolution transmission electron microscopy, including in situ observation, and differential scanning calorimetry. There is contrasting behavior depending on the affinity for interaction or segregation. For reactive systems, compound formation ultimately results, but this can be preceded by solidstate amorphization. For non-reactive systems, crystallization of the metalloid is often achieved with nucleation and growth mediated by the metal phase.

Diffusion-Controlled Nanocrystallization of the Fe73.5Cu1Nb3Si15.5B7 Finemet Amorphous Alloy

2008 ◽  
Vol 570 ◽  
pp. 120-125
Author(s):  
R.M. Ribeiro ◽  
R.S. de Biasi ◽  
D.R. dos Santos ◽  
Dílson S. dos Santos
Keyword(s):  
Differential Scanning Calorimetry ◽  
Amorphous Alloy ◽  
Small Angle ◽  
Nucleation And Growth ◽  
Amorphous Metallic Alloy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Diffusion Controlled

Crystallization of the amorphous metallic alloy Fe73.5 Cu1Nb3 Si8.5 B14 was investigated by ferromagnetic resonance (FMR), small angle in situ X-ray scattering (SAXS/WAXS) and differential scanning calorimetry (DSC). Only one crystalline phase was observed by WAXS and only one peak was observed by DSC. The activation energies, calculated from FMR and DSC data, were 287 kJ.mol-1 and 313.4 kJ.mol-1, respectively. The values calculated for the Avrami exponent were 0.98 (FMR) and 1.4 (DSC). These values correspond to different mechanisms of nucleation and growth; however, the SAXS /WAXS results suggest that the dominant mechanisms are nucleation and growth of crystals from small dimensions.

Preparation and Properties of PLLA-co-bis A/VMT Nanocomposites

2010 ◽  
Vol 150-151 ◽  
pp. 1466-1469
Author(s):  
Ya Li Bai ◽  
Hong Xu ◽  
Zhi Ping Mao
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Thermogravimetric Analyzer ◽  
Melt Polycondensation ◽  
The Fourier Transform

Poly(L-lactic acid)-co-bisphenol-A epoxy resin/vermiculite nanocomposites（PLLA-co-bis A /VMT）were prepared by in-situ melt polycondensation of L-LA in the presence of amino-modified vermiculite. The fourier transform infrared (FTIR) spectra were used to investigate molecular interactions between the modified vermiculite and PLLA. The detailed thermal property and crystallization behavior of samples were studied by using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). The result indicated that the thermal stability, overall crystallization rate and spherulitic texture of PLLA-co-bis A were strongly influenced in the presence of vermiculite particles.

Structural and Electronic Properties of Zr-Ti-Cu-Ni-Be Alloys

2000 ◽  
Vol 644 ◽  
Author(s):  
Jörg F. Löffler ◽  
X.-P. Tang ◽  
Yue Wu ◽  
William L. Johnsona
Keyword(s):  
Differential Scanning Calorimetry ◽  
Small Angle Neutron Scattering ◽  
Crystallization Behavior ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Annealing Temperatures ◽  
Composition Space ◽  
Structural And Electronic Properties

AbstractWe present crystallization studies on Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit1) and on other alloys, where the (Zr,Ti) and (Cu,Be) contents, along the line in composition space connecting Vit1 and Zr46.8Ti8.2Cu7.5Ni10Be27.5 (Vit4), were varied. Results from x-ray diffraction (XRD), small-angle neutron scattering (SANS) and differential scanning calorimetry (DSC) are combined to describe the crystallization behavior of these alloys at deep undercooling. SANS gives evidence for decomposition and the formation of nanometer sized crystals below a critical temperature Tc, which varies drastically as a function of composition. When Tc intersects with the glass transition temperature Tg, changes in the crystallization behavior are observed by DSC and XRD. At annealing temperatures near Tg, XRD resolves quasicrystalline phases for all alloy compositions from Vit1 to Vit4. From 9Be nuclear magnetic resonance (NMR) experiments performed on Vit1 upon annealing, we obtain information about the electronic structure and volume fraction of Be containing crystalline and quasicrystalline phases.

Solid State Reactions in Mechanically Deformed Composites in the Ni-Zr and the Ni-Ti Systems

1989 ◽  
Vol 170 ◽  
Author(s):  
B. E. White ◽  
M. E. Patt ◽  
E. J. Cotts
Keyword(s):  
Solid State ◽  
Amorphous Material ◽  
Nucleation And Growth ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Disordered Phase ◽  
Multilayered Composites ◽  
High Degree

AbstractDifferential scanning calorimetry and x-ray diffraction analysis were utilized to monitor solid state reactions in mechanically deformed Ni/Ti multilayered composites. Solid state reactions at temperatures less than = 650 K result in the formation of a highly disordered phase which is apparently amorphous.The subsequent nucleation and growth at higher temperatures of intermetallic compounds from the amorphous phase is examined. The relatively small thickness of amorphous material (less than 100 Å) which can be grown by solid state reaction in our Ni/Ti samples, combined with the indication that a disordered interface such as that produced by mechanical deformation facilitates these reactions in the Ni-Ti system, may provide some explanation for the relatively high degree of success experienced in the production of amorphous Ni- Ti by means of ball milling. Comparisons are made to results obtained in the Ni-Zr system.

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