Containerless processing of undercooled melts. Final report, 1 March 1989-28 February 1993

Technical Report · Fri Jan 01 00:00:00 EST 1993

OSTI ID:5363708

Perepezko, J H

The investigation focused on the control of microstructural evolution in Mn-Al, Fe-Ni, Ni-V, and Au-Pb-Sb alloys through the high undercooling levels provided by containerless processing, and provided fundamental new information on the control of nucleation. Solidification analysis was conducted by means of thermal analysis, x-ray diffraction, and metallographic characterization on samples processed in a laboratory scale drop tube system. The Mn-Al alloy system offers a useful model system with the capability of phase separation on an individual particle basis, thus permitting a more complete understanding of the operative kinetics and the key containerless processing variables. This system provided the opportunity of analyzing the nucleation rate as a function of processing conditions and allowed for the quantitative assessment of the relevant processing parameters. These factors are essential in the development of a containerless processing model which has a predictive capability. Similarly, Ni-V is a model system that was used to study duplex partitionless solidification, which is a structure possible only in high under cooling solidification processes. Nucleation kinetics for the competing bcc and fcc phases were studied to determine how this structure can develop and the conditions under which it may occur. The Fe-Ni alloy system was studied to identify microstructural transitions with controlled variations in sample size and composition during containerless solidification. This work was forwarded to develop a microstructure map which delineates regimes of structural evolution and provides a unified analysis of experimental observations. The Au-Pb-Sb system was investigated to characterize the thermodynamic properties of the undercooled liquid phase and to characterize the glass transition under a variety of processing conditions.

• Research Organization: Wisconsin Univ., Madison, WI (United States)
• OSTI ID: 5363708
• Report Number(s): N-94-14123; NASA-CR-194350; NAS-1.26:194350; CNN: NAG8-771
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
MICROSTRUCTURE
NUCLEATION
ANTIMONY ALLOYS
GOLD ALLOYS
IRON ALLOYS
LEAD ALLOYS
MANGANESE ALLOYS
NICKEL ALLOYS
VANADIUM ALLOYS
COOLING
PROGRESS REPORT
SOLIDIFICATION
THERMODYNAMIC PROPERTIES
ALLOYS
DOCUMENT TYPES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
360101* - Metals & Alloys- Preparation & Fabrication
360102 - Metals & Alloys- Structure & Phase Studies