Effect of Processing on Microstructure and Mechanical Behavior of Magnesium Oxide

Abstract

Polycrystalline MgO specimens were fabricated from two powders by hot‐pressing in graphite or alumina dies and annealing in air, in vacuum, or within the graphite die in vacuum. Parameters affected were density, grain size, and visual appearance, which was considered to be dependent on grain boundary structure. The formation of a boundary liquid phase with one type of powder tended to eliminate the effect of the processing variables. The character (microstructure) of the specimens was correlated with their mechanical behavior in compression at a constant strain rate at 1200°C.