Metallography of Aluminum Alloys

Metallography of Aluminum Alloys By Lucio F. Mondolfo. PREFACE: In the last few years, a continuous development in the use of alu minum alloys has steadily increased the number of metallurgists inter ested in them. Because of this growing interest and the fact that the most recent books on the subject are now somewhat outdated, it was believed that a new book could be useful. Since many books on the general metallurgy are available, this book has been limited purposely to aluminum alloys. It is intended for consultation by the plant metallurgist, rather than as a textbook for students. For these reasons no details are given on general metallurgy and metallog raphy and most of the theoretical problems have not been treated at all or have been dismissed briefly. The first part of the book illustrates the equilibrium diagrams of aluminum alloys. All information about binary, ternary, and quater nary diagrams published up to date has been sifted, coordinated, and often integrated with data from the authors experiments, to eliminate the discrepancies between the different authors. Usually the discrep ancies are only minor, but at times they are so wide that it has been necessary to report two sets of diagrams. Whenever possible the equilibrium diagrams have been reported graphically, limiting the text to facts about solid solubilities, eutectic and peritectic tempera tures, crystal structures, etc., which could not be represented ade quately in the diagrams. Most of the diagrams are only partial, because, when the complete diagram has not been established beyond doubt, it seemed better not to crowd the book with doubtful details which have no interest for commercial alloys. The same criterion has been applied to the bibliography, which is as complete as possible for the aluminum end of the diagrams but disregards investigations limited to alloys with low aluminum contents. Data about the structures in non-equilibrium conditions caused by rapid cooling have been included whenever possible, and most of these are from experiments by the author, since very little has been published. The scarcity of published material is all the more regrettable as facts about non equilibrium are often more useful than those about equilibrium conditions. The second part is dedicated to the technique of macro-and micro examination. The polishing technique, including electrolytic polish ing and a new fast method developed by the author, is here described. The etching reagents and their technique are also discussed in this part, and a list of the constituents, formed by the alloying elements, is illustrated with carefully selected photo-micrographs to show their typical aspects in commercial alloys. The third part shows the normal structure of the commercial alloys of aluminum. To give as complete a picture of the aluminum field as possible, the alloys commonly used abroad have been in cluded, in addition to those used in the United States. The alloys have been grouped in accordance to their main alloying elements and their general uses and properties are briefly discussed. The eutectics commonly present in the alloys are listed. Great care has been taken to identify for each alloy the lowest melting eutec tics probably less accurate are the data about the high melting point eutectics. The fourth part discusses the effect of fabricating on the microstruc ture, with references to macrostructure and actual practices, when they are necessary for a better understanding of the microstructure...