Solidification and Crystallization (HERLACH:SOLID & CRYSTAL O-BK) || In-Situ Optical Determination of Fraction Solid

✍ Scribed by Herlach, Dieter M.

• Publisher: Wiley-VCH Verlag GmbH & Co. KGaA
• Year: 2005
• Tongue: German
• Weight: 218 KB
• Edition: 1
• Category: Article
• ISBN: 3527310118
• DOI: 10.1002/3527603506.ch14

✦ Synopsis

The fraction solid is a key parameter of solidification describing in an integral way how the mushy zone develops during solidification. In this paper we describe a new technique that measures the fraction solid in-situ, nearly non-invasive optically utilizing a new technique for directional solidification, the aerogel technology developed in the last years. The solidification of an AlSiMg alloy within a transparent silica aerogel mould was observed optically. The intensity readings could be correlated to the temperature profile at the sample surface. Analyzing the intensity profile theoretically yields an expression for the fraction solid as a function of temperature. The results are compared with conventional theories and show remarkable differences that can up to now only explained qualitatively.