The quantitative discrimination between shrinkage and gas microporosity incast aluminum alloys using spatial data analysis

Microporosity in cast aluminum alloys may originate from hydrogen gas evolu tion, microshrinkage, or a combination of both. A spatial analysis method f or the quantitative discrimination between shrinkage and gas porosity is pr esented and explained. It is shown that shrinkage pores can be selected and . analyzed separately from gas pores by nearest neighbor analysis. The prin ciples of spatial statistics are discussed, and the types of spatial point patterns, complete spatial randomness, and nearest-neighbor cluster analysi s are reviewed with respect to microporosity analysis. The pore distributio n of a cast Al-7% Si (A356) foundry alloy is used as an example. (C) Elsevi er Science Inc., 1999. All rights reserved.