TUNGSTEN BASE ALLOYS HOT PRESSED FROM ELEMENTAL POWDERS,
Abstract
The consolidation of refractory metal alloys (80W-10Mo 10Cb and 68W-20Ta-12Mo) from elemental powders of W, Ta, Mo and Cb by mechanical mixing and hot pressing above 2100C was encouraging. A study of compositional uniformity by electron microprobe analysis revealed that the most critical factor in promoting a homogeneous alloy is the starting particle size. Rather uniform composition can be obtained in the hot-pressed condition when all constituent powders are finer than 5 microns. Electron beam melting of these alloys resulted in larger concentration gradients than those obtained by solid state consolidation due to solidification segregation. Cold pressing and sintering resulted in homogeneity equal to the hot pressed material; however, relative density was less than 85 percent after vacuum sintering up to 2800C compared to better than 97 percent in the hot-pressed condition. The high temperature stabilities as indicated by grain growth and hardness measurements are treated. Relative diffusion rates of the alloying elements which control ultimate uniformity are also revealed from the experimental data. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 18, 1964
- Accession Number
- AD0603301
Entities
People
- Jerry E. White
Organizations
- The Aerospace Corporation