scholarly journals Effect of Fe Content on the As-Cast Microstructures of Ti–6Al–4V–xFe Alloys

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 989
Author(s):  
Ling Ding ◽  
Rui Hu ◽  
Yulei Gu ◽  
Danying Zhou ◽  
Fuwen Chen ◽  
...  
Keyword(s):  
Grain Size ◽  
Solidification Process ◽  
Experimental Methods ◽  
Composition Distribution ◽  
Local Composition ◽  
Levitation Melting ◽  
Fe Content ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Solidification Microstructures

In this work, the evolution of the solidification microstructures of Ti–6Al–4V–xFe (x = 0.1, 0.3, 0.5, 0.7, 0.9) alloys fabricated by levitation melting was studied by combined simulative and experimental methods. The growth of grains as well as the composition distribution mechanisms during the solidification process of the alloy are discussed. The segregation of the Fe element at the grain boundaries promotes the formation of a local composition supercooling zone, thus inhibiting the mobility of the solid–liquid interface and making it easier for the grains to grow into dendrites. With the increase in Fe content, the grain size of the alloy decreased gradually, while the overall decreasing trend was mitigated. The segregation of Fe was more obvious than that of Al and V, and the increase in Fe content had less effect on the segregation of Al and V.

Effect of Twin/Tilt on the Growth of Graphite

1984 ◽  
Vol 34 ◽  
Author(s):  
Zhu Peiyue ◽  
Sha Rozeng ◽  
Li Yanxiang
Keyword(s):  
Solidification Process ◽  
Twin Plane ◽  
Liquid Interface ◽  
Tilt Boundary ◽  
Twin Defects ◽  
Solid Liquid Interface ◽  
Graphite Growth ◽  
Solid Liquid

ABSTRACTThe effect of twin/tilt initiated in the process of graphite growth making the graphite curling and change from flake to vermicular and spheroidal is discussed. With the developing of the solidification process,the modifying elements enrich in the front of solid-liquid interface, the amount of twin defects in the graphite increases,its tilt fashion changes and the graphite formed varies from flake to vermicular and spheroidal. The modifying elements promote the formation of twin/tilt. When the modifying elements are insufficient for spheroidizing,the tilt orientation of twins is changeable,and the graphite formed is twisted. When the modifying elements are sufficient enough, the tilt orientation of twins becomes singular, and the graphite formed tends to be round. According to the energy and kinetics consideration of the formation of twin/tilt boundary, it is predicted that the twin plane would firstly adopt (10Tm), especially the (10T2) plane. This result coincides well with the experimental observations. It is proposed that the formation of SG can be divided into two steps: growth of graphite nucleus into spherulite by twin/tilt mechanism and brancing on it in a spiral mode.

scholarly journals Experimental methods for investigating protein adsorption kinetics at surfaces

1994 ◽  
Vol 27 (1) ◽  
pp. 41-105 ◽  
Author(s):  
Jeremy J. Ramsden
Keyword(s):  
Protein Adsorption ◽  
Adsorption Kinetics ◽  
Experimental Methods ◽  
Liquid Interface ◽  
Fundamental Importance ◽  
The Past ◽  
Strong Interest ◽  
Solid Liquid Interface ◽  
Solid Liquid

The adsorption of proteins at the solid-liquid interface is a process of fundamental importance in nature. Extensive reviews (MacRitchie, 1978; Andrade & Hlady, 1986; Norde, 1986) testify to the strong interest which has been shown in the problem during the past few decades. Norde & Lyklema (1978) have rightly pointed out that protein adsorption is scientifically intriguing; the phenomenology is complicated and includes many presently apparently irreconcilable observations.

Solidification of a Liquid Metal with Natural Convection in a Thick-Walled Container

1999 ◽  
Vol 15 (2) ◽  
pp. 47-55
Author(s):  
H. C. Tien ◽  
C.C. Wang
Keyword(s):  
Natural Convection ◽  
Weighting Function ◽  
Solidification Rate ◽  
Thermal Contact ◽  
Solidification Process ◽  
External Cooling ◽  
Implicit Solver ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Change Material

ABSTRACTThe solidification of a phase change material (PCM), exemplified by a molten metal, in a thick-walled container is analyzed in this paper. The effects of natural convection and several important controlling parameters are investigated extensively. These parameters include the initial temperature of the PCM, external cooling conditions, thickness and thermal properties of the wall, and the thermal contact resistance at the PCM/wall interface. Two representative configurations are examined in this study. A modified version of the enthalpy formulation in which the sensible heat is separated from the latent heat, is employed to construct the energy equation for the PCM. Vorticity-stream-function approach is adopted for solving the flow field. The governing equations pertinent to the problem are discretized by the weighting function scheme and finally solved by the SIS (Strongly Implicit Solver) algorithm. It is demonstrated that for both configurations natural convection has prominent effect on the temperature distribution of the liquid phase of the PCM; however, the effect of natural convection on the shape of the solid/liquid interface and the overall solid fraction is case dependent. It is also shown that the above-mentioned controlling parameters have a direct impact on the solidification process. Specifically, an increase in the Biot number (from 1 to infinity) and the thermal diffusivity of the mold (from 0.8 to 5) enhances the solidification rate. Reverse effect was found for the other controlling parameters.

The Mathematical Model Applied to Solidify and Segregation of Ledeburite Tool Steel Ingots

2017 ◽  
Vol 15 (12) ◽  
pp. 28-31
Author(s):  
Vasile Bratu ◽  
Ileana Nicoleta Popescu
Keyword(s):  
Ingot Mold ◽  
Solidification Process ◽  
Height Ratio ◽  
Fluid Equation ◽  
Steel Type ◽  
Solid Diffusion ◽  
Steel Ingots ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Mathematical Model

Abstract In order to determine the optimum geometry of the ingot mold format (the format of ingot mold with a diameter per height ratio H / D <3 and the conicity of minimum 7%) was analyzed by mathematical modeling of solidification and segregation of the carbon and sulfur in it.It was considered 205Cr115 steel type (according with , STAS 3611 - Romanian stardandization) and known also as X210Cr12 steel type (according with European standard). It has been considered an element of volume of coordinates x, y, z in the solidifying ingot and have made the following assumptions: (i) the equilibrium distribution ratio K, is applied to the solid-liquid interface; (ii) solid diffusion is negligible during solidification; and (iii) the solid density is constant during solidification. In carrying out the simulation of segregation mechanisms are resolved heat transfer equation, that simulating the solidification process and are are solved the interdendritic fluid equation of motion.

Experimental Investigation of Fluid Flow and Phase Moving Interface During the Solidification of Binary Mixture in Trapezoidal Cavity

Volume 3 ◽  
2004 ◽  
Author(s):  
C. Ghenai ◽  
R. K. Duggirala ◽  
C. X. Lin ◽  
M. A. Ebadian
Keyword(s):  
Ammonium Chloride ◽  
Binary Solution ◽  
Solidification Process ◽  
Convection Flow ◽  
Initial Concentration ◽  
Moving Interface ◽  
Image Velocimetry ◽  
Convection Patterns ◽  
Solid Liquid Interface ◽  
Solid Liquid

This experimental study focuses on the solidification of a ammonium chloride-water (NH4Cl-H2O) solution in a trapezoidal cavity with one and two vertical cooling walls. The effect of the initial concentration of ammonium chloride (sub-eutectic: f < 19.8% and eutectic f = 19.8%, where f is the percentage in weight) and boundary temperatures (Tcold = −30°C to −10°C) on the solidification process is examined. Particle Image Velocimetry (PIV) is used in this study to measure the velocity fields in the melt during the solidification process. The temperatures distributions at discrete locations in the solution and the boundary walls were measured by 32 thermocouples. The convection flow patterns; the ice shape and thickness; the velocity of the moving liquid/solid interface; and the temperature distribution were obtained. The convection patterns obtained for different initial concentrations showed significant differences. The results showed that the process of solidification is slower with an increase in the initial concentration levels of the binary solution. The growth rate of the frozen layer, the velocity of the moving solid-liquid interface and the temperature in the melt was significantly reduced when increasing the initial concentration of ammonium chloride.

Effect of Cooling Rate on the Microstructure and Precipitates of Directional Solidified 50W600 Non-oriented Silicon Steel

2013 ◽  
Vol 32 (6) ◽  
pp. 597-603
Author(s):  
Yong Wan ◽  
Wei-qing Chen ◽  
Shao-jie Wu
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Silicon Steel ◽  
Growth Region ◽  
State Growth ◽  
Average Size ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Relationship

AbstractThe microstructure, morphologies of precipitates in directional solidified 50W600 non-oriented silicon steel with three cooling rates (0.095, 0.33 and 4.28 °C/s) were investigated. The results showed that the morphology of solid-liquid interface evolved from cellular to cellular dendritic, and then to dendritic with an increase of cooling rate. The grain size of specimen in the steady-state growth region decreased with increasing cooling rate. The precipitates in the steel were mainly four types as follows: AlN, MnS, AlN-MnS and Fe3C. The amount and volume fraction of precipitates firstly increased and then decreased with increasing cooling rate, and reached maximum values in the specimen with a cooling rate of 0.76 °C/s. The average size of precipitates decreased gradually with increasing cooling rate. The relationship between the average size of precipitates and cooling rate was D = 75.762·R−0.190.

Effect of Boron on Solidification Microstructure in a Single Crystal Superalloy

2005 ◽  
Vol 486-487 ◽  
pp. 460-463 ◽  
Author(s):  
Chang Yong Jo ◽  
D.H. Kim ◽  
Yeong Seok Yoo ◽  
D.H. Ye ◽  
Jung Hun Lee
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Directional Solidification ◽  
Melting Temperature ◽  
Liquid Interface ◽  
Solidification Behavior ◽  
Optimum Amount ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Solidification Microstructures

Carbon and boron were mainly considered to strengthen grain boundaries formed during single crystal casting of complex shaped components. However, those elements cause segregation forming the phase with low melting temperature or with brittle nature. To determine the optimum amount of these elements, the effect of boron on solidification behavior was investigated in the C doped single crystal RR 2072 alloy. The solid/liquid interface morphologies and the solidification microstructures were studied at various solidification rates and with B addition by directional solidification.

Influence of vibration on grain size and degree of grain refinement in mild steel weldments

1993 ◽  
Vol 8 (9) ◽  
pp. 2228-2230 ◽  
Author(s):  
S.P. Tewari
Keyword(s):  
Grain Size ◽  
Mild Steel ◽  
Grain Refinement ◽  
Solid Phase ◽  
Steel Plates ◽  
Lower Amplitude ◽  
Experimental Findings ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Fast Removal

Mild steel plates were welded under stationary and dynamic (longitudinal and transverse vibration) conditions. The frequency and amplitude ranges selected were 0 Hz to 300 Hz and 0 μm to 30 μm, respectively. It has been observed on the basis of experimental findings that vibration, in general, reduces the grain size of the weldment, and this reduction is appreciable at a lower amplitude of vibration. This may be due to the lower energy required for nucleation of the solid phase. Fast removal of latent heat of solidification from the solid liquid interface plays a significant part in the grain refinement under vibration.

Numerical Simulation of the Effect of the Size of Nanoparticles on the Solidification Process of Nanoparticle-Enhanced Phase Change Materials

2012 ◽  
Author(s):  
Yousef M. F. El Hasadi ◽  
J. M. Khodadadi
Keyword(s):  
Particle Size ◽  
Phase Change ◽  
Phase Change Materials ◽  
Concentration Field ◽  
Solidification Process ◽  
Liquid Interface ◽  
Constitutional Supercooling ◽  
Fluid Mixture ◽  
Solid Liquid Interface ◽  
Solid Liquid

Nanoparticle-enhanced phase change materials (NEPCM) were proposed recently as alternatives to conventional phase change materials due to their enhanced thermophysical properties. In this study, the effect of the size of the nanoparticles on the morphology of the solid-liquid interface and evolving concentration field, during solidification had been reported. The numerical method that was used is based on the one-fluid-mixture model. The model takes into account the thermal as well as the solutal convection effects. A square cavity model was used in the simulation. The NEPCM that was composed of a suspension of copper nanoparticles in water was solidified from the bottom. The nanoparticles size used were 5 nm and 2 nm. The temperature difference between the hot and cold sides was 5 degrees centigrade and the loading of the nanoparticles that have been used in the simulation was 10% by mass. The results obtained from the model were compared with those existing in the literature, and the comparison was satisfactory. The solid-liquid interface for the case of NEPCM with 5 nm particle size was almost planar throughout the solidification process. However, for the case of the NEPCM with particle size of 2 nm, the solid-liquid interface evolved from a planar stable shape to an unstable dendritic shape, as the solidification process proceeded with time. This was attributed to the constitutional supercooling effect. It has been observed that the constitutional supercooling effect is more pronounced as the particle size decreases. Furthermore, the freezing time increases as the particle size decreases.

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