The Effect of Al-17wt.%Si Alloy Melt Overheating on Solidification Process and Microstructure Evolution

2011 ◽  
Vol 176 ◽  
pp. 29-34 ◽  
Author(s):  
Jaroslaw Piątkowski
Keyword(s):  
Microstructure Evolution ◽  
Solidification Process ◽  
Primary Silicon ◽  
Characteristic Parameters ◽  
Probe Characteristic ◽  
Alloy Solidification ◽  
Silicon Crystals

The effect of overheating on the solidification process and microstructure evolution in AlSi17 silumin was discussed. The alloy melt was held for 40 minutes at 780, 860, 940 and 1020oC, and then cast at a temperature of 780oC to standard ceramic probe. Characteristic parameters of the AlSi17 alloy solidification process, especially Tliq, TE, Tsol, were determined. Examinations of microstructure were also carried out, showing that the higher was the overheating temperature, the higher was the degree of the primary silicon crystals refinement.

scholarly journals Effect of primary silicon crystals on the fluidity of eutectic and hypereutectic Al-Si alloys in lost foam casting

2021 ◽  
Author(s):  
Shailesh Kamble
Keyword(s):  
Process Parameters ◽  
Metal Flow ◽  
Primary Silicon ◽  
Lost Foam Casting ◽  
Minor Role ◽  
Automotive Components ◽  
Silicon Crystals ◽  
A Minor ◽  
Lost Foam

The hypereutectic Aluminum-Silicon (Al-Si) Alloys are gaining impetus in the automotive components, mainly due to their wear resistance. This property in these alloys is derived from the primary silicon crystals. However, there are unique metal flow and mold filling problems associated with hypereutectic Al-Si alloys in Lost Foam Casting (LFC). This investigation is a pioneering work undertaken to gain a better understanding of the role of primary silicon crystals and other phases in the LFC of hypereutectic Al-Si alloys. Time-temperature and first derivative curves were used to determine velocity of metal flow and to calculate solid fractions. Process parameters such as superheat, gating design and alloy composition were manipulated to change the morphology of primary silicon crystals. Microscopy and image analysis of castings enabled study of precipitated particles. Solidification, interlocking and melt sluggishness of precipitated particles significantly influenced fluidity, and the routine process parameters played a minor role.

Study on the Influence of Different Pulse Temperatures on Al-22%Si Alloy Solidification Structure

2011 ◽  
Vol 299-300 ◽  
pp. 566-571
Author(s):  
Zuo Fu Zhao ◽  
Jian Zhong Wang ◽  
Jin Gang Qi ◽  
Shan Dai ◽  
Dong Jun Zhang
Keyword(s):  
Volume Fraction ◽  
Electric Pulse ◽  
Primary Silicon ◽  
Electrical Pulse ◽  
Solidification Structure ◽  
Alloy Solidification ◽  
Modification Effect ◽  
Electric Pulse Modification ◽  
Average Size

Taking the hypereutectic Al-Si alloy as the research object, the fading characteristics of Al-22% Si alloy at different pulse temperatures are investigated in this paper in order to analyze the mechanism of electrical pulse modification to the alloy. We can get the conclusion by observing the microstructure of the sample, measuring the microhardness and calculating the volume fraction and the average size of primary silicon: at different pulse temperatures, the effect of electric pulse modification is fading with static duration prolonging; meanwhile, with the temperature upward, the modification effect and fading trends to be weak, which indicates the best pulse temperature is one of the important factors to influence the modification effect.

Microstructure Evolution in the Atomized Droplets of Mg-9wt%Al Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 1094-1101
Author(s):  
Fei Ding ◽  
Xiao Feng Wang
Keyword(s):  
Droplet Size ◽  
Microstructure Evolution ◽  
Eutectic Reaction ◽  
Solidification Process ◽  
Nucleation And Growth ◽  
Al Alloy ◽  
Microstructure Development ◽  
The Common ◽  
Kinetics Of ◽  
Common Action

A numerical model is developed to describe the kinetics of the microstructure evolution in an atomized droplet of Mg-9wt%Al alloy. The model is coupled with the heat transfer controlling equations to simulate the solidification process of the atomized droplets. The numerical results show that the microstructure development is a result of the common action of the nucleation and growth of grains. The nucleation events take place at a critical supercooling for a given droplet. As the droplet size decreases, the critical supercooling increases significantly. The volume fractions of the phases formed during the period of the recalescence, the segregated solidification and the eutectic reaction are sensitive to the droplet size. It is demonstrated that the developed model describes the microstructure evolution process well.

scholarly journals The Mechanical Properties of AlSi17Cu5 Cast Alloy after Overheating and Modification of CuP Master Alloy

2013 ◽  
Vol 13 (3) ◽  
pp. 68-71
Author(s):  
J. Piątkowski ◽  
M. Jabłońska
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Master Alloy ◽  
Liquid State ◽  
Alloy Composition ◽  
Cast Alloy ◽  
Primary Silicon ◽  
Grain Structure ◽  
Silicon Crystals ◽  
Fine Grain

Abstract The paper presents the results of studies on the effect of the AlSi17Cu5 alloy overheating to atemperature of 920°C and modification with phosphorus (CuP10) on the resultingmechanical (HB, Rm, R0.2) and plastic (A5 and Z) properties. It has been shown that, so-called, "timethermal treatment" (TTT) of an alloy in the liquid state, consisting inoverheating the metal to about 250°C above Tliq,holding at this temperature by 30 minutes improvesthe mechanical properties. It has also been found that overheating of alloy above Tliq.enhances the process of modification, resulting in the formation of fine-grain structure. The primary silicon crystals uniformly distributed in the eutectic and characteristics ofthe α(Al) solution supersaturated with alloying elements present in the starting alloy composition (Cu, Fe) provide not only an increase of strength at ambient temperature but also at elevated temperature (250°C).

Quantitative Examination of Segregation in Slabs for the Production of Sour Service Linepipe

1996 ◽  
Author(s):  
Bernhard Hoh
Keyword(s):  
Statistical Evaluation ◽  
Solidification Process ◽  
Constitutive Relationship ◽  
Computer Assisted ◽  
Characteristic Parameters ◽  
Large Area ◽  
Steel Mills ◽  
Continuously Cast ◽  
Quantitative Examination ◽  
Sour Service

Segregation is a major problem to be overcome by producers of HIC resistant steels. Primary segregation is an inherent and unavoidable feature of the solidification process. The constitutive relationship between solid and liquid stage determines microsegregation and it is influenced by the chemical composition of the steel and its cooling rate. Macrosegregation occurs when microsegregated liquids collect and shift through liquid flow. OREGON STEEL MILLS has conducted systematic measurements on pressure-cast slabs using a computer assisted micro analyzer. This microprobe measures element concentrations over a large area of the specimen. A statistical evaluation based on the frequency distribution of the concentrations forms the basis of a quantitative analysis. From this, characteristic parameters such as the segregation factor and maximum concentration can be derived. This paper discussed the influence of carbon on segregation structure and on segregation properties of manganese, and compares the results with those of continuously cast slabs.

Effect of Rotating Magnetic Field on Microstructure Evolution of Pb-Bi Alloys

2011 ◽  
Vol 311-313 ◽  
pp. 600-608
Author(s):  
Zhao Chen ◽  
Xiao Li Wen ◽  
Chang Le Chen
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Microstructure Evolution ◽  
Solidification Process ◽  
Nucleation And Growth ◽  
Primary Phase ◽  
Rotating Magnetic Field ◽  
Growth Behaviour ◽  
Solidification Behaviour ◽  
40 Hz

Solidification behaviour of Pb-Bi alloys under rotating magnetic field (RMF) was investigated experimentally to understand the effect of the frequency of RMF on the nucleation and growth behaviour. It was found that, as the increase of the rotating frequency, the grains are fragmented and refined gradually until a transition from columnar to equiaxed microstructures happens at a rotating frequency of 40 Hz. Moreover, the Bi concentration of the primary phase decreases and macrosegregation is eliminated effectively with RMF. These are due to the effect of RMF on the nucleation, growth and fluid flow in the solidification process.

Solidification of Al-Pb Alloy under the Effect of Micro-Alloying Element Ti and C

2016 ◽  
Vol 879 ◽  
pp. 2439-2443 ◽  
Author(s):  
Qian Sun ◽  
Hong Xiang Jiang ◽  
Jiu Zhou Zhao
Keyword(s):  
Phase Transformation ◽  
Liquid Phase ◽  
Microstructure Evolution ◽  
Solidification Process ◽  
Miscibility Gap ◽  
Kinetic Behavior ◽  
Number Density ◽  
Alloying Element ◽  
Refinement Efficiency ◽  
Line Temperature

Experiments were carried to investigate the effect of TiC on the solidification process and microstructure of Al-Pb alloys. It is demonstrated that TiC particles are effective inoculants for the nucleation of the Pb-rich droplets during cooling an Al-Pb alloy in the miscibility gap. A model describing the kinetic behavior of TiC particles in the melt and the liquid-liquid decomposition of Al-Pb was developed. The dissolution, coarsening and precipitation processes of TiC particles as well as the microstructure evolution during the liquid-liquid phase transformation of an Al-Pb alloy were calculated. The numerical results indicate that what determines the refinement efficiency of TiC particles on the Pb-rich droplets/particles is the number density of TiC particles in the melt cooled to the binodal line temperature of the Al-Pb alloy. If the number density of TiC particles in the melt before the beginning of the liquid-liquid decomposition is high enough, the addition of TiC causes a refinement of the Pb-rich droplets/particles and promotes the formation of Al-Pb alloys with a well dispersed microstructure.

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