Chapter 4 - Dependence of Castability and Mechanical Properties on Composition and Microstructure of Aluminum Alloys

Abstract

Chapter 4 deals with a very important issue of aluminium foundry alloy castability, its experimental measurements, and dependence upon chemical and phase composition of foundry aluminum alloys. It is important to justify the appearance of yet another book (and chapter) on foundry aluminium alloys. The original first edition of ‘Casting Aluminum Alloys’ published in 2007, is out of print now. As was pointed out above, during some 12+ years that had passed since the 1st edition, many archival papers and several excellent monographs were published on this subject. One of our goals was to provide the reader with an overview of this literature, As it was pointed out in all other chapters of this book, the key distinction of this book from other publications as well as from the 1st edition was to get the interested reader acquainted to the modern simulation and modeling techniques that nowadays find widespread application both in industry and education related to foundry aluminium alloys and their castability. To be able to make a good shaped casting, an aluminium alloy needs to possess good castability. The term ‘good’ is explained: it assumes that a homogeneous casting could be obtained, uniform in its composition without pores and cracks and with the surfaces exactly reproducing the internal geometry of the mould used for the casting process. The level of casting properties is determined by the alloy composition and the technological aspects of the process. Among the most important casting properties, it is necessary to mention liquid fluidity and shrinkage, and associated with them are hot cracking and tendency to the formation of shrinkage porosity and macro-segregation. Therefore, all of these important issues were described in detail, along with the review of the currently available literature and the emerging mathematical modeling techniques.