12/29/2023 0 Comments Dendrites in crystalsDendrites were first observed by polishing metal samples or by etching the polished surface. The metallurgists first observing these crystals thought they resembled trees and called them dendrites, after the Greek word for tree (δένδρον or déndron). The solid aluminum crystals forming during solidification are like snowflakes. This knowledge is an important tool in choosing alloying combinations for your desired result. Even more about alloy properties can be gleaned from delving deeper into how the structure of a metal changes as it freezes. The first article in this series described the use of phase diagrams to see the sequence of phases forming during solidification, which influences final casting properties and can provide insight into castability issues. A brief overview will be given in this article, touching on the aspects of solidification most important to the casting industry. This is a fascinating area, one which has received a great deal of study. The liquid-to-solid transformation involves the formation of many small, individual crystals of solid aluminum. Something similar happens every time metal solidifies in the mold. The variety of snowflakes shown in the book is mind boggling. This claim may be true, in spite of the incredibly large number of snowflakes that form each winter. In the introduction, the author claims each snowflake is unique, and no two crystals are alike. ![]() While the series focuses on solidification principles in aluminum alloys, many can be applied to other metals, as well.Ī book on snowflakes at the Carnegie Library in Pittsburgh depicts many photographs of individual snowflakes. ![]() This article is the second in a series on solidification in aluminum castings. (Click here to see the story as it appears in May's Modern Casting.) Geoffrey Sigworth, GKS Engineering Services, Dunedin, Florida How dendrites form in a casting during solidification informs plant metallurgists of its final properties.
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