The Influence of Mold Material on Cooling Curve, Solidification Parameters, and Micro-hardness of Al–6wt.%Si in Unidirectional Solidification

Improvement of material properties is achieved by controlling parameters involved in the solidification process; therefore, understanding them and their implication are essential. This work investigated the dependency of solidification parameters (cooling rate (TR), growth rate (VL), local solidification time (tSL), temperature gradient (G)), microstructure parameters (primary (λ1) and secondary (λ2) dendrite arm spacing), and micro-hardness values (HV) of Al-4.5wt.%Cu in the clay mold. The samples were directionally solidified in Bridgman vertical apparatus and the temperature is recorded during the cooling. The solidification parameters were obtained from the cooling curve. The microstructures and micro-hardness were characterized using an optical microscope and micro-hardness tester. The microstructure parameters were measured and plotted as functions of solidification parameters using linear regression. The relation between HV and microstructure parameters are analyzed. The results show the λ1 and λ2 change inversely with solidification parameters except for tSL. Comparison to other works shows the exponent values of solidification parameters of the clay mold are lower than that of the carbon and stainless-steel mold. The exponent value of λ2 in the clay mold is -0.183, close to the value in the graphite mold. The clay has the potential as mold material since it characteristic close to the graphite.

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Effect of the High Rotating Magnetic Field (min. 30 mT) on the Unidirectionally Solidified Structure of Al7Si0.6Mg Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.649.263 ◽

2010 ◽

Vol 649 ◽

pp. 263-268 ◽

Cited By ~ 2

Author(s):

Jenő Kovács ◽

Arnold Rónaföldi ◽

András Roósz

Keyword(s):

Magnetic Field ◽

Cross Sections ◽

Interface Velocity ◽

Unidirectional Solidification ◽

Rotating Magnetic Field ◽

The Other ◽

Basic Parameters ◽

Solidification Parameters ◽

Solid Liquid Interface ◽

Solid Liquid

The topic of this paper is the unidirectional solidification of ternary Al7Si0.6Mg aluminium alloy in a rotating magnetic field of 30 -150 mT and the characterisation of effect of stirring on the solidified structure. During performing the experiment-series, one of the three solidification parameters (temperature gradient, solid/liquid interface velocity and magnetic induction) was continuously changed and the other two of them was kept on a constant value. The effect of these parameters on the developed structures was analysed during the evaluation of the experimental results. Moreover, the extent of Si-macrosegregation as well as the change of the secondary dendrite arm spacing were investigated on the longitudinal and cross-sections of samples as a function of the three basic parameters.

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Study on the effect of cooling rate on the solidification parameters, microstructure, and mechanical properties of LM13 alloy using cooling curve thermal analysis technique

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2013.02.088 ◽

2013 ◽

Vol 50 ◽

pp. 7-14 ◽

Cited By ~ 51

Author(s):

V.A. Hosseini ◽

S.G. Shabestari ◽

R. Gholizadeh

Keyword(s):

Mechanical Properties ◽

Thermal Analysis ◽

Cooling Rate ◽

Cooling Curve ◽

Thermal Analysis Technique ◽

Microstructure And Mechanical Properties ◽

Analysis Technique ◽

Solidification Parameters

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Analysis of Cooling Curves, Microstructure and Properties of Chill Cast Al-B4C Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1101.32 ◽

2015 ◽

Vol 1101 ◽

pp. 32-35 ◽

Cited By ~ 6

Author(s):

K.V. Sreenivas Rao ◽

S. Sanman

Keyword(s):

Cooling Rate ◽

Die Casting ◽

Mold Material ◽

Cooling Curves ◽

Test Results ◽

Micro Hardness ◽

Turn On ◽

Chill Cast ◽

Particulate Distribution ◽

Optical Micrographs

The cooling rate depends on the properties of the mold material which has significant influence on the formation of microstructure and in turn on the properties of the cast components. This work is aimed at preparing the Al-B4C composite using different chill materials by gravity die casting and recording the casting temperature during pouring and subsequent solidification to analyze the cooling rate of the casting. The effect of chilling on the microstructure and mechanical properties are determined. The cast specimens are cut and polished by standard metallographic procedure. Optical micrographs are taken at different magnification to reveal the microstructure and B4C particulate distribution. The micro hardness and tensile test results indicate that there is a significant increase in these properties with the increase in B4C content.

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Effect of Mold Material on Boundary Heat Flux Transients during Gravity Die-Casting

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.766-767.405 ◽

2015 ◽

Vol 766-767 ◽

pp. 405-409 ◽

Cited By ~ 1

Author(s):

S. Sanman ◽

K.V. Sreenivas Rao ◽

K.C. Anil

Keyword(s):

Heat Flux ◽

Stainless Steel ◽

Cast Iron ◽

Die Casting ◽

Pure Aluminum ◽

Cooling Curve ◽

Mold Material ◽

Data Logger ◽

Steel Mold ◽

Iron Mold

Experiments were conducted to study the effect of mold material on boundary heat flux variation during gravity die-casting. Inverse method was used for determining heat flux on the inside and outside surface of the mold during casting of pure Aluminum and Al-B4C composites. Different chill materials were used as mold material on one side of the rectangular mold cavity. K- type thermocouples were used for measurement of mold temperature during casting solidification. The mold temperatures at various locations were recorded using a data logger. These measured temperatures were used as input by the inverse algorithm for the assessment of the surface heat flux as a function of time. It was observed that the temperature difference between the inner and outer surface of the copper is very less in comparison to the cast iron mold and stainless steel mold. The cooling curve of the insulation mold indicates that there is no heat transfer through the insulation mold. The boundary heat flux is much higher in the case of copper mold than in the cases of cast iron mold and stainless steel mold.

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Thermal Analysis to Optimize and Control the Cast Iron Solidification Process

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.254.14 ◽

2016 ◽

Vol 254 ◽

pp. 14-19 ◽

Cited By ~ 1

Author(s):

Iulian Riposan ◽

Ion Stefan ◽

Ciprian Firican ◽

Stelian Stan

Keyword(s):

Thermal Analysis ◽

Cast Iron ◽

Solidification Process ◽

Cooling Curve ◽

Specific Factor ◽

Iron Carbides ◽

Coreless Induction Furnace ◽

Eutectic Undercooling ◽

Solidification Parameters ◽

Effect Ratio

The cooling curve and its derivatives display patterns that can be used to predict the characteristics of a cast iron. The effects of melting, superheating and holding in an acid lined coreless induction furnace were explored, as they affect the role of preconditioning and / or inoculation to restore solidification with low eutectic undercooling. Increased chill (iron carbides amount) in the experimental irons correlates well with certain thermal analysis parameters, such as the degree of eutectic undercooling. Preconditioning of the molten base iron before tapping led to improved solidification parameters in both untreated and inoculated irons as measured by the most significant thermal analysis cooling curve events. A double treatment incorporating preconditioning with inoculation improved the thermal analysis parameters, and consequently, the quality of the cast iron. If standard Ca-FeSi alloys do not have sufficient inoculation potential, the addition of the inoculant enhancing alloy (S, O and oxy-sulphides forming elements) will greatly enhance inoculation, well illustrated by changes to the thermal analysis parameters. A newly defined Inoculation Specific Factor [inoculation effect / inoculant consumption which led to that beneficial effect ratio] of different alloys is illustrated by thermal analysis, with good correlation with microstructural characteristics.

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Voids in Quenched Nickel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101074 ◽

1968 ◽

Vol 26 ◽

pp. 266-267

Author(s):

J. J. Laidler

Keyword(s):

Electron Beam ◽

Ambient Temperature ◽

Cooling Rate ◽

Three Dimensional ◽

Cooling Curve ◽

Polycrystalline Nickel ◽

Quenching Temperature ◽

Long Tail ◽

Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

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