Austenitic Grain Growth Characteristics in Rapidly Solidified Martensitic Steels.
Abstract
Comparison of the austenitic grain growth characteristics of conventionally processed and rapidly solidified 9Ni-4Co and 2Mo steels has revealed an unusual resistance to grain coarsening of the rapidly solidified material. At 1200 C where the conventionally processed material coarsens to a grain size of several hundred microns, the rapidly solidified material retains a grain size of approximately 20 micrometers. The morphological characteristics of the inhibited grain growth indicate strong pinning at prior powder particle boundaries. Long-time austenitizing treatments at 1100-1200 C eventually lead to discontinuous coarsening. Evidence so far suggests that the unusual coarsening resistance may be due to finely distributed sulfides. It is anticipated that high austenitizing treatment of rapidly solidified steels will allow improvement of sharp-crack fracture toughness (K sub IC) without the loss of Charpy energy and tensile ductility associated with excessive grain coarsening; exploitation of this phenomenon, however, will require an extreme level of cleanliness in powder processing. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 25, 1980
- Accession Number
- ADA085883
Entities
People
- G. B. Olson
- J. B. Vander Sande
- J. L. Goss
- M. Suga
Organizations
- Massachusetts Institute of Technology