Effect of gravity on three-dimensional coordination number distribution in liquid phase sintered microstructures

✍ Scribed by A. Tewari; A.M. Gokhale; R.M. German

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 613 KB
• Volume: 47
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(99)00164-0

✦ Synopsis

AbstractÐGravity aects microstructural evolution when a liquid phase is present during sintering. The eect of gravity on the three-dimensional coordination number distribution of tungsten grains in liquid phase sintered heavy alloy specimens is quantitatively characterized. A combination of montage serial sectioning, digital image processing, and unbiased stereological sampling procedures is used to estimate the coordination number distribution in three-dimensional microstructures. The microgravity environment decreases the mean coordination number. However, hardly any isolated grains are observed in the specimens, liquid phase sintered in a microgravity environment. The eect of microgravity on the coordination numbers mainly resides in its eect on the mean coordination number. In all specimens, there is a strong correlation between grain size and coordination number, which can be expressed as

where C 0 is the mean coordination number, " D the global average size of the tungsten grains, and D c the average size of only those grains which have coordination number C.