Effect of Isothermal Holding in Solid-Liquid Phase Region on Mg2Si Morphology in Hypereutectic Al-Si In Situ Composite

2012 ◽  
Vol 430-432 ◽  
pp. 711-714
Author(s):  
Zheng Liu ◽  
Hong Biao Xu ◽  
Kai Cao ◽  
Mei Yan Huang
Keyword(s):  
Liquid Phase ◽  
Shape Factor ◽  
Isothermal Holding ◽  
Phase Region ◽  
Holding Time ◽  
In Situ Composite ◽  
Size And Morphology ◽  
Solid Liquid ◽  
Holding Temperature

Mg2Si reinforced hypereutectic Al-Si in-situ composite was prepared and the effects of the isothermal holding temperature and time on Mg2Si in the composite were researched. The results showed that there were the important effects of holding temperature and time in the solid-liquid phase region of the Al-Si alloy on the size and morphology of Mg2Si. The size and morphology of Mg2Si became smaller and round with the rising of the holding temperature and prolonging of the holding time. The suitable technology in the test was obtained, in which when being held at 615°C for 300s, the size of Mg2Si decreased to 20.54μm and the shape factor of Mg2Si reached about 0.67.

Evolution Characteristics of Primary Phase in A356 Al Alloy during Isothermal Holding in Solid-Liquid Phase Region

2011 ◽  
Vol 421 ◽  
pp. 39-42
Author(s):  
Zheng Liu ◽  
Kai Cao ◽  
Hong Biao Xu ◽  
Mei Yan Huang
Keyword(s):  
Liquid Phase ◽  
Isothermal Holding ◽  
A356 Alloy ◽  
Phase Region ◽  
Primary Phase ◽  
Al Alloy ◽  
Evolution Characteristics ◽  
Solid Liquid ◽  
Holding Temperature

Evolution characteristics of primary phase in A356 alloy at the different isothermal holding temperatures and time were investigated. The results showed that there were the effects of the isothermal holding temperature and time on the evolution of primary phase, and microstructure changed from dendritic-like to rosette-like, and then to particle- or globular-like with the decrease of holding temperature. The suitable technology in the test was obtained, in which when being held at 600°C for 5min, the roundness and size of primary became better.

scholarly journals Improved Production and In Situ Recovery of Sesquiterpene (+)-Zizaene from Metabolically-Engineered E. coli

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3356 ◽  
Author(s):  
Francisco Aguilar ◽  
Thomas Scheper ◽  
Sascha Beutel
Keyword(s):  
Liquid Phase ◽  
Product Recovery ◽  
Expanded Bed Adsorption ◽  
Biotechnological Production ◽  
Promising Alternative ◽  
Phase Partitioning ◽  
In Situ Product Recovery ◽  
Solid Liquid ◽  
In Situ Recovery

The sesquiterpene (+)-zizaene is the direct precursor of khusimol, the main fragrant compound of the vetiver essential oil from Chrysopogon zizanioides and used in nearly 20% of men’s fine perfumery. The biotechnological production of such fragrant sesquiterpenes is a promising alternative towards sustainability; nevertheless, product recovery from fermentation is one of the main constraints. In an effort to improve the (+)-zizaene recovery from a metabolically-engineered Escherichia coli, we developed an integrated bioprocess by coupling fermentation and (+)-zizaene recovery using adsorber extractants. Initially, (+)-zizaene volatilization was confirmed from cultivations with no extractants but application of liquid–liquid phase partitioning cultivation (LLPPC) improved (+)-zizaene recovery nearly 4-fold. Furthermore, solid–liquid phase partitioning cultivation (SLPPC) was evaluated by screening polymeric adsorbers, where Diaion HP20 reached the highest recovery. Bioprocess was scaled up to 2 L bioreactors and in situ recovery configurations integrated to fermentation were evaluated. External recovery configuration was performed with an expanded bed adsorption column and improved (+)-zizaene titers 2.5-fold higher than LLPPC. Moreover, internal recovery configuration (IRC) further enhanced the (+)-zizaene titers 2.2-fold, whereas adsorption velocity was determined as critical parameter for recovery efficiency. Consequently, IRC improved the (+)-zizaene titer 8.4-fold and productivity 3-fold from our last report, achieving a (+)-zizaene titer of 211.13 mg L−1 and productivity of 3.2 mg L−1 h−1. This study provides further knowledge for integration of terpene bioprocesses by in situ product recovery, which could be applied for many terpene studies towards the industrialization of fragrant molecules.

Effect of Isothermal Holding Temperature on Globularization of Primary Solid Phase in Multiplex-Type Slurry Cup

2006 ◽  
Vol 116-117 ◽  
pp. 239-242 ◽  
Author(s):  
Suk Won Kang ◽  
Dock Young Lee ◽  
Ki Bae Kim
Keyword(s):  
Automobile Industry ◽  
Solid Phase ◽  
Isothermal Holding ◽  
Cost Effective ◽  
Al Alloy ◽  
Liquid Region ◽  
Globular Structure ◽  
Semi Solid ◽  
Solid Liquid ◽  
Holding Temperature

In order to produce a high quality and cost effective part in the rheocasting process for an automobile industry it has been important to develop a slurry-on-demand process, which can manufacture the semi-solid slurry having a fine and globular structure of primary solid phase. The morphology of primary solid phase of semi-solid slurry is coarsened and globularized during an isothermal holding process in a solid-liquid region. Accordingly, in this paper, the microstructural evolution of semi-solid slurry during the isothermal holding at a various temperature in solid-liquid region was investigated to examine a coarsening and globularization behavior of primary solid phase. The semi-solid slurry of Al alloy was produced in a slurry maker using a multiplex-type slurry cup that we developed recently. A size of primary solid phase was the finer at the higher holding temperature, but under a constant holding time a roundness degree of primary solid phase was the lower at the lower holding temperature. Also, a coarsening rate of primary solid phase was not considered to be affected significantly by a holding temperature even though a little lower coarsening rate was obtained at the higher holding temperature.

Microstructural Evolution of AZ31 Mg Wrought Alloy during Partial Remelting for Thixoextrusion

2006 ◽  
Vol 116-117 ◽  
pp. 251-254
Author(s):  
Young Ok Yoon ◽  
Shae K. Kim
Keyword(s):  
Grain Size ◽  
Microstructural Evolution ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Holding Time ◽  
Interesting Point ◽  
Grain Sizes ◽  
Partial Remelting ◽  
Average Grain Size ◽  
Holding Temperature

An attempt has been made to investigate feasibility of thixoextrusion for AZ31 Mg wrought alloy through simple partial remelting. Microstructural evolution of AZ31 Mg wrought alloy for thixoextrusion was investigated as functions of isothermal holding temperature and time in the partially remelted semisolid state. The interesting point of this study was that the thixotropic structures of AZ31 Mg wrought alloy without additional pretreatment could be obtained through simple partial remelting. The uniform average grain size and liquid fraction according to the isothermal holding time were very important for the thixoextrusion. Because, it is must be considered on actual extrusion time. The liquid fraction was increased with increasing isothermal holding temperature and time. But, the liquid fraction was almost uniform after 10 min. The average grain size was decreased with increasing isothermal holding temperature. On the other hand, as the holding time increased, the average grain sizes were uniform at 615 and 622. This phenomenon is very useful for thixoextrusion in terms of process control such as actual extrusion time.

scholarly journals The Simulation of the Preparation of the Ingot With Liquid Core

2021 ◽  
Author(s):  
yongqiang wu ◽  
Zhi-ren Sun ◽  
Kaikun Wang
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Liquid Phase ◽  
Solid Phase ◽  
Liquid Core ◽  
Phase Region ◽  
Simulation Results ◽  
Solid Liquid ◽  
Deform 3D ◽  
Ultra High Temperature

Abstract During the preparation of the ingot with liquid core in the early stage, the finite element models of the solidification and the ultra-high temperature demoulding were established in DEFORM-3D. The thermophysical properties of ASSAB 718 with the variations of C, Mn and Cr were calculated in JMatPro®. The material database was imported into DEFORM-3D. Through the analysis of the finite element simulation results, we obtained the influence of three main elements C, Mn and Cr contents on the size of the solid-phase region, the liquid-phase region and the solid-liquid two-phase region in the ingot. We optimized the composition of the material to get a wide solid-liquid phase range. The high carbon, the medium manganese and the high chromium contents were beneficial to form the liquid core. Based on the method of the solidification time, the algorithm was programmed by the python language. We analyzed the influence of the three elements C, Mn, and Cr on the concentration distribution based on the temperature field data, which were obtained by DEFORM-2D after the solidification and the ultra-high temperature demoulding. According to the simulation results, we found that the region prone to negative segregation.

scholarly journals OPTIMIZATION OF SYNTHESIS PROCESS OF NANOSTRUCTURED CARBIDE-CORUNDUM SILUMIN MODIFIER

2021 ◽  
Vol 1 (54) ◽  
pp. 71-79
Author(s):  
Dmitry V. ORDA ◽  
Keyword(s):  
Mathematical Model ◽  
Titanium Carbide ◽  
Response Function ◽  
Isothermal Holding ◽  
Holding Time ◽  
Synthesis Process ◽  
Synthesis Parameters ◽  
Response Equation ◽  
Main Factors ◽  
Holding Temperature

A mathematical model is developed for the process of synthesis of nanostructured modifier TiC-Al2O3 by gasphase deposition based on the system of starting materials TiO2-Al-C. To construct the response equation in the form of a polynomial of the second degree, the experiments were carried out in accordance with the model of a rotatable composite plan of the second order with three factors, including 20 experiments. The main factors considered were the isothermal holding temperature T (°C), the isothermal holding time t (s), and the proportion of the chlorinating component Q (wt.%), and as a response function — the proportion of titanium carbide q(TiC) (wt.%) in the composition of the synthesized modifier. The paper describes the results of computational and experimental modeling, from which it can be concluded that to obtain a modifier with the highest content of titanium carbide, the synthesis parameters should be as follows: T = 900–930 °C; t = 2–2.5 h; Q = 4–4.5 wt.%. The resulting TiC-Al2O3 modifier contains 34 wt.% TiC and has a nanostructured structure, with spherical and filamentous particles which diameter does not exceed 100 nm.

scholarly journals A Parametric Study of Solute Redistribution During Transient Liquid Phase Diffusion Bonding Process

2001 ◽  
Vol 7 (6) ◽  
pp. 387-396
Author(s):  
Tien-Chien Jen ◽  
Yuning Jiao ◽  
Thomas Hwang
Keyword(s):  
Liquid Phase ◽  
Mushy Zone ◽  
Diffusion Bonding ◽  
Parametric Study ◽  
Transient Liquid Phase ◽  
Bonding Process ◽  
Holding Time ◽  
Solute Redistribution ◽  
Liquid Zone ◽  
Holding Temperature

A parametric study is performed to investigate the solute redistribution during the transient liquid phase (TLP) diffusion bonding process. The macroscopic solute diffusion in the liquid and the solid phase, as well as the solid transformation to the liquid due to solute macrosegregation, are considered in this study. The effects of the following parameters are considered: ratio of solute diffusivity in liquid and solid state alloy(ξ=Dl/Ds), holding temperatures(θ), a combined parameter related to solidus and liquidus slopes in the phase diagram(ϕ), and the re-melting and re-solidification time(τ). The thickness of the pure liquid zone and the mushy zone of the TLP diffusion bonding process are demonstrated with respect to the above-mentioned parameters. It is shown numerically that the holding time, the holding temperature, and solute diffusivity ratio influence the solute distribution strongly, which in turn influences the liquid zone and mushy zone thickness significantly. It is concluded that for the TLP diffusion bonding process, the optimal technique parameters are high holding temperature, long holding time, and a large liquidus and solidus temperature slope ratio(ml/ms)of the interlayer material.

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