In order to study microstructural inhomogeneity of tungsten heavy alloys, 78W-15.4Ni-6.6Fe tungsten heavy alloys that were liquid phase sintered under both ground-based and microgravity conditions were investigated. Standard metallographic procedures were used to obtain optical micrographs. Microstructural inhomogeneity was observed in both ground based and microgravity samples. Parameters, such as solid volume fraction, contiguity, connectivity and area equivalent grain size increased from the top to the bottom in the ground-based sample, and increased from the periphery to the center in the microgravity sample. A digital image analysis approach called tessellation was employed to measure the liquid phase area distributions. Histograms of the measured liquid phase areas were plotted. 3D computer simulation was conducted to obtain random microstructures. Comparing with the random microstructures, liquid phase area distributions were found inhomogeneous in both ground based and microgravity samples.
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