A New Method of Characterization on Microstructure of Casting Alloy

2011 ◽  
Vol 211-212 ◽  
pp. 122-126
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu
Keyword(s):  
Fractal Dimension ◽  
Fractal Structure ◽  
A356 Alloy ◽  
Fractal Dimensions ◽  
Primary Phase ◽  
New Method ◽  
Casting Alloy ◽  
Microstructural Characteristics ◽  
Low Superheat

Microstructural characteristics of A356 alloy prepared by low superheat pouring were researched, and the fractal dimensions of morphology of primary phase in the alloy was calculated. The results indicated that morphology of primary phase in A356 alloy belonged to fractal structure, and the microstructural characteristics in the alloy can be characterized by fractal dimension. There were the different fractal dimensions for the morphology of primary phase prepared by the different process.

Fractal Characteristics of Primary Phase Morphology in Semisolid A356 Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 936-940
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu
Keyword(s):  
Fractal Dimension ◽  
A356 Alloy ◽  
Fractal Dimensions ◽  
Processing Parameters ◽  
Primary Phase ◽  
Phase Morphology ◽  
Box Counting ◽  
Magnetic Stirring ◽  
Fractal Characteristics ◽  
Electro Magnetic

Semisolid A356 alloy was prepared by low superheat pouring and slightly electro- magnetic stirring(LSPSES). The fractal dimensions of primary phase morphology in semisolid A356 alloy were researched by the calculating program written to calculate the fractal dimensions of box-counting in the image of primary phase morphology in semisolid A356 alloy. The results indicated that the primary phase morphology in the alloy was characterized by fractal dimension, and the morphology obtained by the different processing parameters had the different fractal dimension. The morphology at the different position of ingot had the different fractal dimensions, which reflected the effect of solidified conditions at different position in the same ingot on the morphology in the alloy. Solidification of the alloy was a course of change in fractal dimension.

Study on Fractal Characteristics of Primary Phase Morphology in Semi-Solid A356 Alloy

2010 ◽  
Vol 139-141 ◽  
pp. 653-656
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu
Keyword(s):  
Fractal Dimension ◽  
A356 Alloy ◽  
Fractal Dimensions ◽  
Primary Phase ◽  
Phase Morphology ◽  
Fractal Characteristic ◽  
Box Counting ◽  
Compound Process ◽  
Fractal Characteristics ◽  
Semi Solid

Semi-solid A356 slurry was prepared by compound process, and the fractal characteristic of primary phase morphology was researched. The fractal dimensions of primary phase morphology in semi-solid A356 alloy were calculated by the calculating program written to calculate the fractal dimensions of box-counting in the imagine of morphology of semi-solid primary phase in A356 alloy. The results indicated that the primary phase morphology in semi-solid A356 prepared by compound process is characterized by fractal dimension, and the primary phase morphology prepared by the different technology parameters had different fractal dimensions. The primary phase morphology at the different position of ingot had the different fractal dimensions, which reflected the effect of solidified conditions at different position in the same ingot on the morphology of semi-solid primary phase

ON THE DYNAMICAL EVOLUTION OF THE FRACTAL STRUCTURE OF INTERSTELLAR MEDIUM

Fractals ◽  
1993 ◽  
Vol 01 (04) ◽  
pp. 908-916 ◽  
Author(s):  
Z.Y. YUE ◽  
B. ZHANG ◽  
G. WINNEWISSER ◽  
J. STUTZKI
Keyword(s):  
Fractal Dimension ◽  
Interstellar Medium ◽  
Density Distribution ◽  
Fractal Structure ◽  
Initial Conditions ◽  
Initial Density ◽  
Dynamical Evolution ◽  
Fractal Dimensions ◽  
Compressible Turbulence ◽  
Initial States

Two-dimensional compressible turbulence in a self-gravitating, magnetic interstellar medium is calculated as an initial value problem. It is shown that even if the initial density distribution is homogeneous and the initial velocity distribution contains only a few Fourier components, the nonlinear interaction among the Fourier components will generate more and more Fourier components and lead to a turbulent and fractal structure in the interstellar medium. The calculations are carried out for three different initial states. In order to see the time evolution, detailed density distributions and fractal dimensions of the density contours are calculated at three moments of time for each of the initial states. The results show that the fractal dimension remains almost the same (~1.4–1.5), although the detailed density distribution has changed considerably. The insensibility of the fractal dimension of density contours to both the initial conditions and the evolution time is in good agreement with observations of molecular clouds in the interstellar medium.

scholarly journals The linkage between box-counting and geomorphic fractal dimensions in the fractal structure of river networks: the junction angle

2020 ◽  
Vol 51 (6) ◽  
pp. 1397-1408
Author(s):  
Xianmeng Meng ◽  
Pengju Zhang ◽  
Jing Li ◽  
Chuanming Ma ◽  
Dengfeng Liu
Keyword(s):  
Fractal Dimension ◽  
Fractal Structure ◽  
Fractal Dimensions ◽  
River Networks ◽  
Stream Length ◽  
Box Counting ◽  
Linear Relationships ◽  
Box Counting Dimension ◽  
Junction Angle

Abstract In the past, a great deal of research has been conducted to determine the fractal properties of river networks, and there are many kinds of methods calculating their fractal dimensions. In this paper, we compare two most common methods: one is geomorphic fractal dimension obtained from the bifurcation ratio and the stream length ratio, and the other is box-counting method. Firstly, synthetic fractal trees are used to explain the role of the junction angle on the relation between two kinds of fractal dimensions. The obtained relationship curves indicate that box-counting dimension is decreasing with the increase of the junction angle when geomorphic fractal dimension keeps constant. This relationship presents continuous and smooth convex curves with junction angle from 60° to 120° and concave curves from 30° to 45°. Then 70 river networks in China are investigated in terms of their two kinds of fractal dimensions. The results confirm the fractal structure of river networks. Geomorphic fractal dimensions of river networks are larger than box-counting dimensions and there is no obvious relationship between these two kinds of fractal dimensions. Relatively good non-linear relationships between geomorphic fractal dimensions and box-counting dimensions are obtained by considering the role of the junction angle.

Characterization on Primary Phase Morphology of Semisolid A356 Alloy during Isothermal Holding with Fractal

2012 ◽  
Vol 531-532 ◽  
pp. 67-72 ◽  
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu
Keyword(s):  
Fractal Dimension ◽  
Fractal Theory ◽  
Isothermal Holding ◽  
A356 Alloy ◽  
Primary Phase ◽  
Phase Morphology ◽  
Processing Conditions ◽  
Alloy Solidification ◽  
Fractal Character ◽  
Holding Temperature

Semisolid A356 alloy was prepared by low superheat pouring, and evolution of primary phase morphology in semisolid A356 alloy during isothermal holding was characterized by fractal theory. The results indicated that the primary phase morphology in the alloy had fractal character, and the evolution of the primary phase morphology in the alloy could be characterized by fractal dimension. The primary phase morphology at the different isothermal holding temperature and holding time had the different fractal dimension, which meant the effect of processing conditions on the morphology in the alloy. Solidification of the alloy was a course of change in fractal dimension.

Fractal Characteristics of Microstructure in Semisolid A356 Alloy

2011 ◽  
Vol 204-210 ◽  
pp. 1575-1578 ◽  
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu
Keyword(s):  
Fractal Dimension ◽  
A356 Alloy ◽  
Fractal Dimensions ◽  
Fractal Characteristic ◽  
Compound Process ◽  
Fractal Characteristics

The fractal characteristic of microstructure in semisolid A356 alloy was researched by the calculating program written to calculate the fractal dimensions. The results indicated that the morphology of primary grain in semisolid A356 prepared by compound process is characterized by fractal dimension, and the morphology of primary grain at the different position of ingot had the different fractal dimensions, which reflected the effect of solidified conditions at different position in the same ingot on the morphology of semisolid primary grain.

Detection of Wear Condition of Micro Milling Cutters Based on Length Fractal Dimension

2014 ◽  
Vol 577 ◽  
pp. 697-700
Author(s):  
Zhi Qiang Wang ◽  
Gui Ying Zhang ◽  
Bin Liu
Keyword(s):  
Fractal Dimension ◽  
Time Domain ◽  
Fractal Dimensions ◽  
Experimental Results ◽  
New Method ◽  
Micro Milling ◽  
Vibration Signals ◽  
Reference Samples ◽  
Wear Condition

In this paper, a new method to realize online wear detection of micro-milling cutters based on length fractal dimension is proposed. On the basis of expression derivation of length fractal dimension, experiments are conducted. First, several cutters with different wear condition are chosen as reference samples. Their multi-section vibration signals in time-domain are collected and the clustering domain δ of each sample are obtained based on length fractal dimensions. Then, the vibration signals of tested cutters are monitored and analysed in time domain, thus their length fractal dimension are abstracted. Comparing the length fractal dimension of tested cutters with the clustering domain δ of reference samples, the wear condition of tested cutters are detected. The experimental results show that the length fractal dimension of each tested cutter falls in the clustering domain corresponding to the actual wear condition.

Microstructure Refinement by Y2O3 in Semisolid A356 Alloy

2011 ◽  
Vol 311-313 ◽  
pp. 666-669
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu ◽  
Yong Mei Hu
Keyword(s):  
Grain Size ◽  
A356 Alloy ◽  
Particle Morphology ◽  
Primary Phase ◽  
Microstructure Refinement ◽  
Α Phase ◽  
Low Superheat

The semisolid A356 alloy slurry, which was grain-refined by Y2O3, was manufactured by low superheat pouring. The effects of grain-refine on the morphology and the grain size of the primary phase in semisolid A356 alloy were researched. The results indicated that semisolid A356 alloy contained Y2O3 with particle-like and rosette-like primary phases could be prepared by low superheat pouring. The grain size and particle morphology of primary phase in semisolid A356 alloy were markedly improved by Y2O3. The refining mechanism of Y2O3 on the morphology and the grain size of the primary α phase in semisolid A356 alloy was delved.

Effect of Eutectic Reaction Induced by La on Microstructure in Semisolid A356 Alloy

2012 ◽  
Vol 424-425 ◽  
pp. 77-80
Author(s):  
Zheng Liu ◽  
Mei Yan Huang ◽  
Kai Cao ◽  
Hong Biao Xu
Keyword(s):  
Eutectic Reaction ◽  
A356 Alloy ◽  
Primary Phase ◽  
La Addition ◽  
Size And Morphology ◽  
Low Superheat

Semisolid A356 alloy was prepared by low superheat pouring. The effects of La as a kind of refinement on the size and morphology of the primary phase in semisolid A356 alloy were researched. The results indicated that semisolid A356 alloy contained certain La addition with particle-like and rosette-like primary phase could be prepared by low superheat pouring. The size and morphology of primary phase in A356 alloy are markedly improved by the suitable addition of La. The refining mechanism of La on the size and morphology of the primary phase in semisolid A356 alloy were concerned with the eutectic reaction induced by La in the alloy.

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