Accession Number:

ADA250789

Title:

Fundamental Studies of Beta Phase Decomposition Modes in Titanium and Related Alloy Systems

Descriptive Note:

Final rept. 30 Sep 1989-31 Mar 1992

Corporate Author:

CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s):

Report Date:

1992-03-31

Pagination or Media Count:

51.0

Abstract:

Throughout this final grant from AFOSR, the P.I. spent much of his time in the preparation of generic overviews of numerous major topics in diffusional phase transformations. These overviews dealt with homogeneous nucleation, interphase boundary structures in Ti-base alloys, effects of interphase boundary structure upon growth kinetics, shear vs. diffusional transformation mechanism with emphasis upon linking macroscopic observations with processes proceeding at the atomic level, the mechanism and definitions of the bainite reaction and the influence of alloying elements upon the growth kinetics of grain boundary allotriomorphs of proeutectoid ferrite. A major overview of the ledge mechanism in vapor-crystal, liquid-crystal and crystal-crystal diffusional phase transformations, and a still broader overview of atomic mechanisms of diffusional nucleation and growth are nearing completion. Collaborative research with Dr. M. G. Hall of the University of Birmingham, U.K., on topics concerned with distinction between diffusional and shear mechanisms of transformation from the standpoints of crystallography and surface relief effects, has also made progress.

Subject Categories:

  • Physical Chemistry
  • Properties of Metals and Alloys
  • Crystallography
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE