Accession Number : ADA462032
Title : Alpha/Beta Heat Treatment of a Titanium Alloy with a Non-Uniform Microstructure (Preprint)
Descriptive Note : Journal article
Corporate Author : AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
Personal Author(s) : Semiatin, S. L. ; Lehner, T. M. ; Miller, J. D. ; Doherty, R. D. ; Furrer, D. U.
Report Date : AUG 2006
Pagination or Media Count : 42
Abstract : The effect of alpha/beta solution temperature and cooling rate on the evolution of microstructure during the heat treatment of Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti6242Si) with a partially-spheroidized starting microstructure of equiaxed + remnant lamellar alpha was established. Experiments comprising induction heating to a peak temperature of 971 or 982 degrees C followed by cooling at a rate of 11 or 42 degrees C/min revealed that the volume fraction of the equiaxed alpha grew much more rapidly than the lamellar constituent. These results were explained semi-quantitatively using simple diffusion analyses of the growth of either spherical or elliptical particles, taking into account the soft-impingement of the concentration fields. Despite the much lower diffusivity of molybdenum, which appears to control the growth of primary alpha in Ti6242Si, the similarity of the overall kinetics compared to those measured previously for Ti-6Al-4V was explained on the basis of the higher supersaturations developed during cooldown in the present alloy.
Descriptors : *MICROSTRUCTURE , *TITANIUM ALLOYS , *SOLUTION HEAT TREATMENT , COOLING , NONUNIFORM , IMPINGEMENT , DIFFUSIVITY , SUPERSATURATION
Subject Categories : METALLURGY AND METALLOGRAPHY
PROPERTIES OF METALS AND ALLOYS
Distribution Statement : APPROVED FOR PUBLIC RELEASE