Accession Number:

ADA214424

Title:

Fundamental Studies of Beta Phase Decomposition Modes in Titanium Alloys

Descriptive Note:

Final rept. 1 Oct 1988-30 Sep 1989

Corporate Author:

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

Report Date:

1989-10-31

Pagination or Media Count:

79.0

Abstract:

An experimental investigation of the interfacial structure of the broad faces of windmanstatten alpha plates and of grain boundary alpha allotriomorphs formed in a Ti-7.15 WO 6.62 AO Cr alloy has been completed. A supporting modeling study was also made of the structure of these BCC HCP interfaces, using both a computer modeling technique and the bollmann O-lattice method. No misfit dislocations were found at any of the interfaces examined on either morphology. Instead, c- or ca-type misfit-compensating ledges of variable height eliminated the need for one set of misfit dislocations structural ledges removed the requirement for the other set. The former ledges were readily imaged with conventional tem they are straight and uniformly spaced. Direct observation of structural ledges required the use of atomic resolution tem. Hot-stage tem confirmed the mobility of growth ledges and the immobility of c-type ledges. Alloys, Phase transformations, Beta phase decomposition. jes

Subject Categories:

  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE