Evaluation of Effects of Rare Earth Element and Cooling Rate on the Eutectic Reaction of Flake Graphite Cast Irons by Cooling Curve Analysis

The Al-Cu alloys have been widely used in aerospace, automobile, and airplane applications. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys for grain refinement. The cooling curve analysis (CCA) has been used extensively in metal casting industry to predict microstructure constituents, grain refinement and to calculate the latent heat of solidification. The aim of this study is to investigate the effect of cooling rate and grain refinement on the thermal and thermodynamic characteristics of Al-Cu alloys by cooling curve analysis. To do this, Al-Cu alloys containing 3.7, and 4.8 wt.% Cu were melted and solidified with 0.04, 0.19, 0.42, and 1.08 K/s cooling rates. The temperature of the samples was recorded using a K thermocouple and a data acquisition system connected to a PC. Some samples were Grain refined by Al-5Ti-1B to see the effect of grain refinement on the aforementioned properties. The results show that, in a well refined alloy, nucleation will occur in a shorter time, and a undercooling approximately decreases to zero. The other results show that, with considering the cooling rate being around 0.1 °C/s, the Newtonian method is efficient in calculating the latent heat of solidification.

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Cooling curve analysis in binary Al-Cu alloys: Part I- Effect of cooling rate and copper content on the eutectic formation

Metallurgical and Materials Engineering ◽

10.30544/80 ◽

2015 ◽

Vol 21 (3) ◽

pp. 195-206 ◽

Cited By ~ 2

Author(s):

M. Dehnavi ◽

F. Kuhestani ◽

M. Haddad-Sabzevar

Keyword(s):

Cooling Rate ◽

Latent Heat ◽

Copper Content ◽

Time Derivative ◽

Weight Percent ◽

Curve Analysis ◽

Cooling Curve ◽

Copper Addition ◽

Cooling Curve Analysis ◽

First Time

There are many techniques available for investigating the solidification of metals and alloys. In recent years computer-aided cooling curve analysis (CA-CCA) has been used to determine thermo-physical properties of alloys, latent heat and solid fraction. In this study, the effect of cooling rate and copper addition was taken into consideration in non- equilibrium eutectic transformation of binary Al- Cu melt via cooling curve analysis. For this purpose, melts with different copper weight percent of 2.2, 3.7 and 4.8 were prepared and cooled in controlled rates of 0.04 and 0.42 °C/s. Results show that, latent heat of alloy highly depends upon the post- solidification cooling rate and composition. As copper content of alloy and cooling rate increase, achieved nonequilibrium eutectic phase increases that leads to release of high amount of latent heat and appearing of second deviation in cooling curve. This deviation can be seen in first time derivative curve in the form of a definite peak.

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Investigation the solidification of Al-4.8 wt.%Cu alloy at different cooling rate by computer-aided cooling curve analysis

Metallurgical and Materials Engineering ◽

10.5937/metmateng1402107d ◽

2014 ◽

Vol 20 (2) ◽

pp. 107-118 ◽

Cited By ~ 1

Author(s):

Mehdi Dehnavi ◽

Hosein Vafaeenezhad ◽

Mohsen Haddad Sabzevar

Keyword(s):

Cooling Rate ◽

Alloy Composition ◽

Data Acquisition System ◽

Structural Features ◽

Curve Analysis ◽

Cooling Curve ◽

Cooling Curves ◽

Cu Alloy ◽

Cooling Curve Analysis ◽

Computer Aided

Depending on the casting conditions and alloy composition, microstructure and properties of the aluminium alloys will be different. There are many techniques available for investigating the solidification of metals and alloys. In recent years computer-aided cooling curve analysis (CA-CCA) has been used to determine thermophysical properties of alloys, latent heat and solid fraction. The aim of this study was to investigate the effect of cooling rate on the structural features of Al-4.8 wt.%Cu alloy by thermal analysis of cooling curves. To do this, Al-4.8 wt.%Cu alloy was melted and solidified applying 0.04, 0.42, and 1.08 °C/sec cooling rates. The temperature of the samples was recorded using a K thermocouple and a data acquisition system connected to a PC. It was found that the formation temperatures of various thermal parameters such as (liquidus, solidus and eutectic temperatures) are shifting by increasing of cooling rate from 0.04 °C/sec to 1.08 °C/sec. The structural results show that grain size and secondary dendrite arm spacing decreased by increasing of cooling rate.

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The Study of Solidification Behavior in Cast Irons Using the Linear Displacement Method

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.263.77 ◽

2017 ◽

Vol 263 ◽

pp. 77-81

Author(s):

Sarum Boonmee ◽

Letrit Chuencharoen

Keyword(s):

Linear Expansion ◽

Linear Displacement ◽

Curve Analysis ◽

Cooling Curve ◽

Carbon Equivalent ◽

Solidification Behavior ◽

Displacement Method ◽

Solidification Shrinkage ◽

Cast Irons ◽

Cooling Curve Analysis

This study aims to assess the solidification shrinkage and expansion during the solidification of cast irons. The solidification shrinkage and expansion in cast irons are due to the formation of austenite and graphite respectively. In this study, the linear displacement method was used to observe the solidification event combined with the cooling curve analysis. It was found that the cooling and displacement curves show good correlations in time of events during solidification. The displacement due to graphite expansion increased with the carbon equivalent. The linear expansion of 0.2 to 1.9 mm was observed for the carbon equivalents ranged from 3.7 to 4.5. On the other hand, the displacement due to the austenite shrinkage was found to decrease with increasing carbon equivalents.

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