Structural Characterization of Schladitz Whiskers.
Abstract
Polycrystalline iron whiskers containing 1.5 w/o C and O.8% O have an extraordinary ultimate tensile strength between 6 and 8 GPa. Their microstructure has been investigated by transmission electron microscopy and electron diffraction techniques. it has been found that the whiskers consist of alpha-Fe grains between 2 nm and 30 nm in diameter which do not have sharp boundaries but are separated by a wide boundary region. A microdispersion of alpha-Fe, Fe3O4, Fe3C, alpha-/fe2O3 and carbon is prevalent throughout the whisker volume. Again, no sharp phase boundaries seem to exist which could imply a transitional region between second phase particles characterized by a concentration gradient and mixed covalent and metal bonding. It is concluded that a new strengthening mechanism for alloys is responsible for the mechanical properties of CVD produced steel whiskers. This mechanism requires a grain size below 30 nm, non-planar grain boundaries and a microdispersion of particles of iron oxides, iron carbides and carbon. Also, the covalent/metallic bonding mix within the transition region between the minute second phase particles and the alpha-Fe matrix is considered an essential component of the strengthening mechanism.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1982
- Accession Number
- ADA115098
Entities
People
- H. G. F. Wilsdorf
Organizations
- University of Virginia