Shape distortion in liquid-phase-sintered tungsten heavy alloys
- Pennsylvania State Univ., University Park, PA (United States). Engineering Science and Mechanics Dept.
Shape retention during liquid phase sintering is a major concern at high liquid contents, or large density differences between the solid and the liquid phases. This study demonstrates the role of microstructural parameters in controlling the bulk dimensional changes that occur during liquid phase sintering of tungsten heavy alloys (WHAs). Tungsten-nickel-copper alloys containing 80 wt pct tungsten, the balance containing Ni and Cu in the ratio 6:4, 7:3, or 8:2, were sintered at temperatures between 1400 C and 1500 C. Compact distortion was quantified using a coordinate measuring machine and related to the microstructural parameters, such as solid volume fraction, grain size, dihedral angle, grain contiguity, and connectivity. Supplementary experiments were performed on W-Ni, W-Cu, and Mo-Cu alloys to compare the role of microstructural parameters in controlling distortion. A low solid solubility and a small grain size coupled with a high dihedral angle and connectivity restrict distortion. Based on the experimental observations and stereological relations, the critical solid content required to maintain structural rigidity is related to specific combinations of dihedral angle and grain connectivity.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 669753
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 29, Issue 10; Other Information: PBD: Oct 1998
- Country of Publication:
- United States
- Language:
- English
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