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

Mehdi Dehnavi,Hosein Vafaeenezhad,Mohsen Haddad Sabzevar

doi:10.5937/metmateng1402107d

Abstract

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.

Highlights

The Al-Cu alloys have been widely used in aerospace, automobile, and airplane applications
To investigate the effect of cooling rate on the solidification processing, specimens with dimensions (D×H) 22×20 mm and ~10g weight were melted inside a Differential Thermal Analysis (DTA) furnace in an alumina crucible (Figure.1)
Microstructure The microstructure of Al-Cu alloys is controlled by chemical composition and cooling rate

Summary

Introduction

The Al-Cu alloys have been widely used in aerospace, automobile, and airplane applications. Depending on the casting conditions and alloy composition, microstructure, properties and characteristics of the aluminum alloys will be different[1]. All industrial casting processes operate in a certain range of cooling rates. This range can be as low as 0.01 °C/sec for a massive sand casting, and can be as high as 105 °C/sec upon rapid solidification of granules and flakes. Operate in the range of cooling rates between 0.1 and 20 °C/sec.

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