An Investigation of Diffusion in the Columbium Vanadium System
Abstract
Diffusion rates in the Cb-V system were investigated using electron microprobe analysis of the diffusion zones to determine concentration gradients. The interdiffusion coefficient, D, was found using a computer program to solve the Matano-Boltzman method. Activation energies, Q, and frequency factors, Do, were derived from values of D at the same concentrations but at different temperatures. A partial list of Do and Q for interdiffusion (in lattice parameter measure) as a function of composition is: 5 a/o Cb; Q = 59.8 Kcal/mol, Do = 5.3x10 to the 16th power 1 sq P/hr; 55 a/o Cb; Q = 48.1 Kcal/mol, Do = 9.5x10 to the 14th power 1 sq P/hr; 95 a/o Cb; Q = 69.4 Kcal/mol, Do = 7.0x10 to the 15th power 1 sq P/hr. Movement of tungsten Kirkendall markers at 12.7 a/o Cb and 1404 degree C. during the diffusion anneal indicated D sub V > D sub Cb. Diffusion in the Cb-V system is apparently by a vacancy mechanism.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1962
- Accession Number
- AD0610234
Entities
People
- Robert C. Geiss
Organizations
- Air Force Institute of Technology