Effect of the aspect ratio of mica crystals and crystallinity on the microhardness and machinability of mica glass-ceramics

Abstract

The change in the microhardness and machinability of mica glass-ceramic is related closely to its microstructural parameters. The aspect ratio of the crystals, the volume crystallinity and the spatial arrangement of the particles must be considered in order to be able to estimate the characteristics of the material. With a high aspect ratio and crystallinity, the microhardness decreases because of high connectivity. By introducing the effective crystallinity, indicating the effectiveness of disk-like crystals in forming a connected structure of crystals, the variation in microhardness can be explainable. A steep decrease in the microhardness of mica glass-ceramics occurs due to the connection of the mica crystals, leading to good machinability. (C) 1997 Elsevier Science S.A.