Accession Number : ADA135956

Title :   Synthesis and Properties of Elevated Temperature P/M Aluminum Alloys.

Descriptive Note : Annual technical rept. 1 Oct 82-30 Sep 83,

Corporate Author : NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Fine,M E ; Weertman,J R

PDF Url : ADA135956

Report Date : 29 Nov 1983

Pagination or Media Count : 47

Abstract : High temperature alloys in order to maintain thier strength during long time exposure at high temperatures must have stable microstructures. The dispersed phase coarsening rates in the A1-7.5Fe-3.5Ce and A1-10Fe-1.5Mo-1V alloys, developed for high temperature applications, were compared at 475 and 575 C. To the extent that the average intercept length cubed, L3, is a linear function of time during isothermal aging, after an initial transient, the particle coarsening obeys the Lifshitz-Slyozov-Wagner theory. The interfacial energies estimated from the coarsening rates using the theory of particle coarsening show that the interfaces between the particles and matrix are high energy incoherent interfaces. The dispersed particles in the A1-10Fe-1.5Mo-1V alloy coarsen faster at both temperatures than the particles in the A1-7.5Fe-3.5Ce showing that the latter alloy is more stable at these temperatures. Since the diffusion in diffusion controlled coarsening usually occurs by a vacancy mechanism, plastic deformation should increase the rate of particle coarsening since plastic deformation increases the vacancy concentration. This has been confirmed in combined creep and coarsening studies with the A1-7.5Fe-3.5Ce alloy.

Descriptors :   *Aluminum alloys, *Heat resistant alloys, *Physical properties, Powder metallurgy, Thermal stability, Microstructure, Iron alloys, Cerium alloys, Vanadium alloys, Molybdenum alloys, Plastic deformation, Mechanical properties

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE