AEROSOL PREPARATION OF COMPOSITE METAL POWDERS FOR DISPERSION STRENGTHENING
Abstract
The feasibility of utilizing aerosolization apparatus for preparing composite metal powders of value in the preparation of high-temperature dispersion-strengthened metals was demonstrated in the Ni-alumina, Ni-chromic oxide and Ta-alumina systems. The aerosolization apparatus produces, from bulk powders, individually dispersed particulate clouds which at the instant of separation re individuall coated with the composite-forming shell material. Refractory coatings have been dispersed on micron-sized preformed metal particles in order to provide materials analogous to the starting powders of the SAP process. Preformed submicron refractory particles acting as deposition nuclei have also been coated with metal shells by gas-phase chemical reaction of a volatile metal compound. After extrusion, chromic oxide particles dispersed in Ni had a mean free path of 0.5 microns. Ta with dispersed submicron alumina showed a mean free path of 1 micron. Judging by electron microscopic criteria, these metals should have superior hightemperature properites in fabricated shapes to the limit of stability of the dispersed phase and possibly to 0.9 of the homologous temperature. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1961
- Accession Number
- AD0257716
Entities
People
- C.d. Mckinney
- W.b. Tarpley