Abstract
The compressive and diametral tensile strength, and hardness were measured for a single phase spherical alloy of non-γ_2 type, Dialloy, and a conventional spherical alloy, Hiatomic M. Fracture surface was also observed in order to study the relationship of the fracture to the microstructure. The variation of the mercury content from the standard one significantly decreased the compressive strength and hardness. The compressive strength dropped markedly when the alloy was mixed with 27 and 29% of mercury for Dialloy and Hiatomic M, respectively, as well as with 62 and 60% of mercury for each. The γ phase particles in the set amalgam were much more porous and softer than the original unreacted one, and could not be materially the same as the unreacted γ phase. These particles remained in the set amalgam should not be defined as the unreacted γ phase particles. At lower M/A ratio, the fracture occured through the matrix in a collapsing manner because of the embrittlement due to the poor matrix formation. At the standard or higher M/A ratio, the fracture passed preferentially through the voids, γ_2 phase in Hiatomic M, and the grain boundaries of the γ_1 phase in the matrix, and the porous and brittle residual alloy particles. The fracture seemed to be unlikely to pass the γ_1 phase. Clear differences can not be detected in both the two amalgams.
