Abstract
Preforms of nickel powder or nickel/alumina powder blends were infiltrated with molten aluminum to produce nickel aluminides. Application of a pressure of 3.6 and 6.9 MPa on the melt allowed infiltration of preforms with nickel powder particles between 5 and 15 μm in diameter, which could not be infiltrated under the sole action of capillary forces. By varying the initial preform temperature from 705 °C to 280 °C, the diameter of nickel powder particles from 15 to 150 μm, and the volume fraction of alumina from 0 to 34 vol pct, pressure-infiltrated samples with large variations in the extent of reaction between nickel and aluminum were pro- duced. The range of microstructure extended from fully reacted nickel aluminide to essentially unreacted nickel/aluminum samples containing low levels of final porosity. In particular, it was found that reducing the initial preform temperature below the melting point of aluminum results in a reduction of the rate and extent of aluminide formation, allowing, in turn, reduction of macrosegregation within the resulting infiltrated material.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2161-2170 |
| Number of pages | 10 |
| Journal | Metallurgical Transactions A |
| Volume | 24 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 1993 |
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys