Effects of annealing on the microstructure and mechanical properties of hot pressed BaAl{sub 2}Si{sub 2}O{sub 8} (BAS) and SrAl{sub 2}Si{sub 2}O{sub 8} (SAS) glass-ceramics

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:96553

Buzniak, J J; Dickerson, R M; Lagerlof, K P.D. ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (United States); and others

The crystallization behavior, microstructural development during annealing, and the four point bend strength of hot-pressed BaO{center_dot}Al{sub 2}O{sub 3}{center_dot}2SiO{sub 2} (BAS) and SrO{center_dot}Al{sub 2}O{sub 3}{center_dot}2SiO{sub 2} (SAS) glass ceramics have been investigated. Both BAS and SAS show strength loss above the glass transition temperature ({approximately}900{degrees}C), suggesting the presence of residual glass along the grain boundaries in the hot pressed material. Annealing of BAS at temperature above 1000{degrees}C, resulted in an increase of the bend strength when tested above its glass transition temperature. However, increasing porosity during annealing caused a decrease of the fracture strength at temperatures below the glass transition with respect to the as-hot-pressed material. The increased porosity is believed to be associated with the formation of gaseous reaction products during annealing.

• OSTI ID: 96553
• Report Number(s): CONF-940416--; CNN: Grant NCC-133; Grant NCC3-236
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
ANNEALING
BARIUM OXIDES
GLASS
GRAIN SIZE
HOT PRESSING
MECHANICAL PROPERTIES
MICROSTRUCTURE
PHASE TRANSFORMATIONS
SILICA
STRONTIUM OXIDES
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE