Accession Number : AD0659666

Title :   THE EFFECT OF LANTHANUM AND YTTRIUM ON THE RECRYSTALLIZATION OF MOLYBDENUM,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Goltsev,V. P.

Report Date : 28 FEB 1967

Pagination or Media Count : 9

Abstract : Specimens of sintered molybdenum alloys containing 0.06--0.2% lanthanum or 0.03--0.1% yttrium were vacuum annealed at 1673K, rolled at 1133K with a total reduction of 70%, and again vacuum annealed at 1173--1873K to determine the effect of La and Y on the alloy recrystallization behavior. It was found that additions of up to 0.1% yttrium or up to 0.2% lanthanum insignificantly increase the temperature of the beginning of recrystallization. On the other hand, even very small additions of yttrium or lanthanum (0.03--0.06%) sharply increase the temperature of the end of recrystallization. The temperature range between the beginning and the end of recrystallization of molybdenum alloy containing lanthanum or yttrium is rather wide and reaches 250--300K. In alloy with 0.2% lanthanum, the first recrystallized grains are formed at 1273K and the recrystallization ends at 1573K. At 1673K, the grain growth begins, but the grain size does not exceed 20--25 microns. Only at 1873K does the grain size increase substantially. Lanthanum and yttrium react with interstitial impurities and act as deoxidizers refining the grain boundaries. It appears that the recrystallization behavior of the alloys tested is a result of the presence of finely dispersed particles of the secondary phase, the products of deoxidation. (Author)

Descriptors :   (*RECRYSTALLIZATION, *MOLYBDENUM), (*METALS, RECRYSTALLIZATION), (*METALLURGY, ALLOYS), LANTHANUM, TRANSITION TEMPERATURE, YTTRIUM, METALS, ELECTROLYTIC POLISHING, DEFORMATION, ANNEALING, HARDNESS, CERMETS, TEMPERATURE, MICROSTRUCTURE, X RAY PHOTOGRAPHY, USSR

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE