Growth and crystallization of YAG- and mullite-composition glass fibers

This paper describes a new process to synthesize crystalline oxide fibers f or high temperature structural applications. Strong and chemically homogene ous precursor fibers of 5-40 mu m diameter were made at rates of up to 1.6 m s(-1) by glass fiber pulling techniques from undercooled molten oxides. T he precursor fibers were heat treated at temperatures up to 1873 K to make crystalline fibers with controlled grain size and properties. Tensile stren gths of the precursor fibers were up to 5-6 GPa (900 ksi) for YAG- (Y3Al5O1 2) and mullite- (Al6Si2O13) compositions. Research to optimize fiber compos itions and crystallization processes, and to scale up precursor fiber produ ction is discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.