Microstructure and thermal stability of lamellar Cr-silicides
Additional Document Info
Directional solidification of Cr-Cr3Si eutectic alloys in an optical floating zone furnace can produce well-aligned, fully lamellar microstructures, consisting of alternating lamellae of Cr3Si and a Cr-Si solid solution. The lamellar spacing was found to vary inversely with square root of growth rate, consistent with predictions of the Jackson-Hunt theory. At very low and high growth rates the lamellar structure breaks down and yields degenerate and cellular structures, respectively. Elevated temperature exposures cause the lamellar structures to spheroidize rapidly. Microalloying elements have been identified that significantly slow down the coarsening kinetics of the Cr-Cr3Si lamellae.