Microstructure Analysis of Melt-Spun Al3Ti Intermetallics by XRD and EXAFS

1996 ◽  
Vol 460 ◽  
Author(s):  
Jinmin Chen ◽  
W. E. Frazier ◽  
E. V. Barrera
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Melt Spinning ◽  
Composition Range ◽  
Processing Parameters ◽  
Wheel Speed ◽  
Annealing Temperatures ◽  
Melt Spun ◽  
Temperature Heat ◽  
Spinning Process

ABSTRACTIn an effort to expand the composition range over which Al3Ti is stable, various amounts of niobium were substituted for titanium and processed by melt-spinning. Several samples were annealed both at 600°C and 1000°C for 24 hours. The effects of processing parameters such as wheel speed, the amount of niobium, and annealing temperatures on the structure were investigated by XRD and EXAFS. XRD showed that for all the samples the only structure present was DO22-The DO22 structure was stable even after the high temperature heat treatments. By means of EXAFS, niobium atoms were observed to occupy titanium sites in the DO22 structure. Furthermore, in the unannealed samples, increasing wheel speed of the melt spinning process or the niobium concentration tended to distort the crystal structure. It was observed that Ti EXAFS had different results from the Nb EXAFS beyond their occupying similar sites, which suggested there may exist some composition zones, i.e. rich Nb zone or rich Ti zones, although the structures present were still DO22. The samples were found to experience different distortions as a function of annealing temperatures.

Optimization of Manufacturing Parameters for Melt Spun Yarns Using Taguchi Method

2014 ◽  
Vol 556-562 ◽  
pp. 4264-4267
Author(s):  
Shu Wen Wang ◽  
Te Li Su
Keyword(s):  
Taguchi Method ◽  
Melt Spinning ◽  
Parameter Design ◽  
Controllable Factors ◽  
Melt Spun ◽  
Spun Yarns ◽  
Spinning Process ◽  
Polypropylene Melt ◽  
Manufacturing Parameters

In melt spinning process, evenness of polypropylene melt spun yarns affects the appearance, hairiness, strength and productivity of yarns, as well as product production and profits, causing rejection due to nonconformity. The research is to find optimal manufacturing parameters of melt spun yarns. Firstly, to proceed the parameter design by Taguchi method, then to select a manufacturing parameter which will affect the quality of melt spun yarns as controllable factors. Also to choose a suitable orthogonal arrays. Meanwhile, according to variation of analysis, to decide optimal manufacturing parameters of melt spun yarns and its remarkable factor. Finally, using 95% confidence interval to proof the experiment’s reliability and repeatability.

Recrystallization of Amorphous or Nanocrystalline NdBa2Cu3O7−x and GdBa2Cu3O7−x

1992 ◽  
Vol 275 ◽  
Author(s):  
T. J. Folkerts ◽  
S. I. Yoo ◽  
Youwen Xu ◽  
M. J. Kramer ◽  
K. W. Dennis ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Xrd ◽  
Melt Spun ◽  
Temperature Heat ◽  
Higher Temperature ◽  
Xrd Studies ◽  
Melt Spinning Technique

ABSTRACTUsing a novel melt-spinning technique, we have produced highly disordered NdBa2Cu3O7−x and GdBa2Cu3Oy−x materials. Samples which were melt-spun in an O2 environment consist of nanocrystals with the tetragonal REBa2Cu3O7−x structure: samples which were processed in an N2 environment consist of an amorphous matrix with small amounts of crystalline BaCu2O2, as shown by x-ray diffraction and electron microscopy. High temperature XRD studies indicate that the BaCu2O2 is eliminated during heating to 500°C in O2 and that the REBa2Cu3O7−x Phase recrystallizes directly from the amorphous matrix at temperatures below 800°C. Preliminary magnetization measurements show that higher temperature heat treatments are needed to restore superconductivity.

scholarly journals The Effect of External Magnetic Field on Microstructure and Magnetic Properties of Melt-Spun Nd-Fe-B/Fe-Co Nanocomposite Ribbons

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xuan Truong Nguyen ◽  
Hong Ky Vu ◽  
Hung Manh Do ◽  
Van Khanh Nguyen ◽  
Van Vuong Nguyen
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
High Performance ◽  
Melt Spinning ◽  
Nominal Composition ◽  
Energy Product ◽  
Melt Spun ◽  
Spinning Process ◽  
Reduction Effect ◽  
Microstructure And Magnetic Properties

The ribbons Nd2Fe14B/Fe-Co were prepared with the nominal composition Nd16Fe76B8/40% wt. Fe65Co35by the conventional and the developed magnetic field-assisted melt-spinning (MFMS) techniques. Both ribbons are nanocomposites with the smooth single-phase-like magnetization loops. The 0.32 T magnetic field perpendicular to the wheel surface and assisting the melt-spinning process reduces the grain size inside the ribbon, increases the texture of the ribbon, improves the exchange coupling, and, in sequence, increases the energy product(BH)maxof the isotropic powdered samples of MFMS ribbon in ~9% by comparison with that of the ribbon melt-spun conventionally. The grain size reduction effect caused by the assisted magnetic field has also been described quantitatively. The MFMS technique seems to be promising for producing high-performance nanocomposite ribbons.

scholarly journals A Study of the Mechanical Behavior and Crystal Structure of UHMWPE/HDPE Blend Fibers Prepared by Melt Spinning

2018 ◽  
Vol 13 (3) ◽  
pp. 155892501801300
Author(s):  
Fei Wang ◽  
Lichao Liu ◽  
Ping Xue ◽  
Mingyin Jia ◽  
Hua Sun
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Behavior ◽  
Melt Spinning ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Melt Flow Index ◽  
Flow Index ◽  
Scanning Calorimetry ◽  
Spinning Process

Ultrahigh molecular weight polyethylene (UHMWPE) and high-density polyethylene (HDPE) blend fibers with the highest tensile strength of 1.13 GPa were prepared by a melt spinning process. The crystal structure and mechanical behavior of the as-spun filaments and fibers were studied by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), sound velocity orientation test and tensile strength test. The results suggested that the degree of molecular chain orientation, crystallinity and mechanical properties of the blend fibers were improved by blending with the low melt flow index (MFI) HDPE. The crystal grains of low MFI HDPE blend fibers that were formed by more highly oriented molecular chains could be stretched more effectively in the drawing direction, and the improved mechanical properties were due to the more regular and compact crystal structure.

Development of disperse dyes polypropylene fiber and process parameter optimization Part II: Dyeable polypropylene fiber production and melt spinning process parameter optimization

2017 ◽  
Vol 88 (13) ◽  
pp. 1505-1516 ◽  
Author(s):  
Chung-Feng Jeffrey Kuo ◽  
Wei-Lun Lan ◽  
Ming-Yan Dong ◽  
Shih-Hsiung Chen ◽  
Fang-Sian Lin
Keyword(s):  
Tensile Strength ◽  
Parameter Optimization ◽  
Melt Spinning ◽  
Polypropylene Fiber ◽  
Processing Parameters ◽  
Process Parameter ◽  
Disperse Dye ◽  
Process Parameter Optimization ◽  
Washing Fastness ◽  
Spinning Process

The industry uses color masterbatch mixing process and spinning for dope dyeing. There are color mending and color passivation appearance problems, and the process is inapplicable to functional apparel textiles. In this study, dyeable modified polypropylene (PP) fabric with disperse dye will be developed. The modified polyester material and PP for compounding processing with a compatibilizer will be used to make chips and the quality engineering method will be applied to analyze the optimum spinning process parameters. The fabric will be used to validate the dye washing fastness and light fastness in order to implement the dyeability of PP modified disperse dye. The optimum processing parameters to develop dyeable PP fiber will be studied. The modified materials are made into fiber by melt spinning, and the fuzzy C means technique is combined with the stem cells algorithm to design and analyze the processing parameters for the quality characteristics of tensile strength and elongation. The optimum fully drawn yarn is made. The tensile strength of the fiber of optimum parameter design is 3.66 g/d, higher than the 3.36 g/d of the pure PP fiber; the elongation is 38.65%, higher than the 36.66% of pure PP fiber, meaning the optimization method could improve the characteristics in melt spinning process, and conform with the standards of the textile industry. The fiber derived from the optimum parameters is woven into fabric for the disperse dyeing test and the validation of washing fastness shows the washing fastness is Level 3–4, meaning that the developed modified PP fabric has good dye-uptake and fastness.

Structure and Size Distribution of Powders Produced from Melt-Spun Fe-Si-B Ribbons

2021 ◽  
Vol 876 ◽  
pp. 25-30
Author(s):  
Rosa M. Aranda Louvier ◽  
Raquel Astacio Lopez ◽  
Fátima Ternero Fernández ◽  
Petr Urban ◽  
Francisco G. Cuevas
Keyword(s):  
Size Distribution ◽  
Melt Spinning ◽  
Nanocrystalline Structure ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Homogenization Time ◽  
Melt Spun ◽  
Spinning Process ◽  
Amorphous Character ◽  
Ejection Pressure

This work studies the production of melt spun Fe78Si9B13 ribbons with amorphous or nanocrystalline structure. The main objective is the preservation of the amorphous structure after obtaining powders by mechanical milling of the ribbons, as well as the study of the influence of the milling conditions on the size distribution and structure of the obtained powders. In order to obtain high quality amorphous ribbons, the wheel rotation speed, crucible-wheel distance, melt homogenization time, ejection pressure and the ejection temperature were optimized in the melt spinning process. Different mills were used for powder production, studying the size distribution, efficiency, and preservation of the amorphous character as a function of the milling time. Ribbons and powders were characterized by X-ray diffraction (XRD) and electron microscopy (SEM and TEM); laser diffraction was used for powder granulometry.

Effect of Grain Size on the Shape Recovery in a Melt-Spun Fe-24%Mn-4%Si-5%Cr-5%Co SMA Ribbon

2012 ◽  
Vol 488-489 ◽  
pp. 315-320
Author(s):  
H.J. Kim ◽  
K.K. Jee ◽  
H.W. Kang ◽  
J.K. Lee ◽  
G.S. Yang ◽  
...  
Keyword(s):  
Grain Size ◽  
Melt Spinning ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Deformation Mode ◽  
Wheel Speed ◽  
Bulk Specimen ◽  
Mean Grain Size ◽  
Melt Spun ◽  
Ε Martensite

Effect of grain size on microstructure, transformation characteristics and shape recovery has been studied in Fe-24%Mn-4%Si-5%Cr-5%Co shape memory ribbons fabricated by melt spinning. Mean grain size of the ribbons could be controlled by wheel speed; in case of ribbon manufactured in the wheel speed of 10 m/sec, mean grain size was more or less 20 μm, while the mean grain size in 50 m/sec was about 1 μm. Thermal ε-martensite in the shape of plate could be observed in austenite matrix and the volume fraction of that decreased in smaller grains because of grain constraint. As a grain size decreased, one-way and two-way shape recoveries were increased. A change in shape recovery of ribbons was closely related to deformation mode i.e., transformation-induced plasticity or slip according to grain size; it could be confirmed that reversible ε-martensite was induced in preference to irreversible slip in the ribbon with smaller grains during deformation by X-ray diffractometry. Not like in bulk specimen, ε-martensite being very thin in the width of 10 ~ 20 nm and lots of stacking faults being inferred from streaks of SAD patterns, were revealed in melt-spun ribbons manufactured in the wheel speed of 50 m/sec.

Microstruoture-Property Relationships in Magenqubnch Magnets

1987 ◽  
Vol 96 ◽  
Author(s):  
Raja K. Rishra
Keyword(s):  
Melt Spinning ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Processing Parameters ◽  
Second Phase ◽  
Lorentz Microscopy ◽  
Transmission Electron ◽  
Melt Spun ◽  
Magnetic Domain Walls ◽  
Two Phases

ABSTRACTTransmission electron microscopy has been used to characterize the microstructure of Nd-Fe-B magnets produced by melt-spinning and subsequent hot-pressing/die-upsetting. For a material of starting composition Nd.135Fe.815B.05, the basic microstructure od melt-spun, hot-pressed and dieupset magnets consists of two phases. In the optimally processed melt-spun ribbons and hot-pressed samples, small and randomly oriented Nd2Fe14B grains are surrounded by a thin noncrystalline Nd-rlch phase. The die-upset material consists of closely stacked flat Nd2Fe14B grains surrounded by a second phase of approximate composition Nd7Fe3. No Nd11Fe4B4 phase is observed in these materials, but it can form if the chemical composition and/or processing parameters are varied. In all these materials, Lorentz microscopy reveals that magnetic domain walls are pinned by the second phase. The differences in the hard magnetic properties of the three kinds of MAGNEQUENCH magnets closely correlate with the differences in the distribution of Nd2Fe14B crystallites and the pinning sites.

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