Microstructure as an essential aspect of EN AW 7075 aluminum alloy quality influenced by electromagnetic field during continuous casting process

Aleksandra Pataric,Andreja Radovanovic,Marija Mihailovic,Miroslav Sokic,Branka Jordovic,Branislav Markovic

doi:10.2298/hemind201214006p

Abstract

Microstructure assessment is crucial for the design and production of high-quality alloys such as cast aluminum alloy ingots. Along with the effect of a more homogeneous microstructure to result in much better mechanical properties, better as-cast alloy quality indicates a higher efficiency of the aluminum alloys production process. During the aluminum alloy solidification process many microstructural defects can occur, which deteriorate the mechanical properties and hence decrease the usability of such an ingot. Application of the electromagnetic field during the vertical continuous casting process significantly reduces occurrence of these defects. In the present study, EN AW 7075 alloy samples were cast with and without application of an electromagnetic field and examined regarding the microstructure, electrical conductivity, and changes in the phase composition. The obtained results clearly show that it is possible to decrease or avoid casting defects by the electromagnetic field application as verified by the microstructure characterization and quantification, electrical conductivity tests and differential thermal analysis (DTA).

Highlights

Electromagnetic casting, a technology that links magneto-hydrodynamics and casting provides possibilities that could have never been attained by the conventional casting process [1]
We have studied the effects of casting with the electromagnetic field (EMF) application on the microstructure of the EN AW 7075 aluminum alloy
A more dendritic microstructure of the sample 1 obtained without the application of EMF is evident as compared to microstructures of the other two samples, which are finer and exhibiting more distinctive cells

Summary

INTRODUCTION

Electromagnetic casting, a technology that links magneto-hydrodynamics and casting provides possibilities that could have never been attained by the conventional casting process [1]. Electromagnetic casting was used with the aim to produce better ingot surfaces, as confirmed in literature [2] This is enabled by a convex surface meniscus formed at the liquid metal/mold interface as a result of a balance of acting forces. A. PATARIĆ et al.: MICROSTRUCTURE AS AN ASPECT OF EN AW 7075 ALUMINUM ALLOY QUALITY with uneven grain sizes leading to segregation and cracks, which usually appear during the conventional casting and solidification process. PATARIĆ et al.: MICROSTRUCTURE AS AN ASPECT OF EN AW 7075 ALUMINUM ALLOY QUALITY with uneven grain sizes leading to segregation and cracks, which usually appear during the conventional casting and solidification process These effects may limit exploitation of such a superior construction alloy, by diminishing the quantity of usable casting. Great savings in energy and production time can make this process superb

EXPERIMENTAL

AND DISCUSSION

CONCLUSION