Accession Number : AD0695874

Title :   KINETICS OF TRANSFORMATIONS IN THE BETA SOLID SOLUTION OF THE MAGNESIUM-INDIUM SYSTEM,

Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) DIV OF APPLIED CHEMISTRY

Personal Author(s) : Pickwick,K. M. ; Alexander,W. A.

Report Date : 07 JUN 1969

Pagination or Media Count : 8

Abstract : Decomposition of the intermediate beta solid solution of the magnesium-indium system has been examined in respect of the characteristics and kinetics of the reactions, using a resistometric technique. The beta phase undergoes ordering of the type AI to LI(2) (beta') in alloys containing up to 39% indium, and AI to LI(0) (beta'') between 39 and 55% indium. Both transitions occur with great rapidity, and the disordered state could not be retained at any temperature below T(c). This behaviour is discussed with reference to the transformation kinetics expected of such first order reactions. Precipitation from the ordered solid solutions occurs within narrow homogeneity ranges at Mg3In beta(1) and Mg2In beta(2), although there are extensive two-phase regions about these compositions. The beta(1) phase forms by continuous precipitation, and the formal kinetics of the reaction have been determined. For beta(2), the precipitation changes from the continuous to the discontinuous mode as the indium concentration is increased through the stoichiometric composition. (Author)

Descriptors :   (*MAGNESIUM ALLOYS, *PHASE DIAGRAMS), (*INDIUM ALLOYS, *PHASE STUDIES), MICROSTRUCTURE, SOLID SOLUTIONS, METALLOGRAPHY, CANADA

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE