Mechanisms and Kinetics of Surface Alloying by Diffusion-Induced Grain Boundary Migration.
Abstract
The recently recognized phenomenon of diffusion-induced grain boundary migration has been systematically investigated to determine conditions under which this effect occurs and to establish the mechanism and driving forces that control this process. This migration and the surface alloying that accompanies it were observed in a number of different alloy systems, including Cu-Zn, Cu-As, Au-Pd, Fe-Zn, Fe-Cr, and Fe-As. Detailed tests in the Ag-Au alloy system using thin layers of diffusant deposited on a metal substrate and analyses of liquid phase sintering experiments in Mo-Ni base alloys indicated that the driving force for diffusion-induced grain boundary migration depends on lattice parameter variations in the alloy. Connections were made between diffusion-induced grain boundary migration in solid alloy systems and liquid film migrations that occur during liquid phase sintering. A coherency stress theory proposed by Hillert was extended to provide predictions concerning these effects. This theory then was used to select ceramic systems in which migrations might occur and as a result diffusion-induced liquid film migration was observed for the first time in a ceramic system. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1985
- Accession Number
- ADA161671
Entities
People
- C. A. Handwerker
- D. B. Butrymowicz
- J. R. Manning
- J. W. Cahn
Organizations
- National Institute of Standards and Technology