Accession Number : ADA019048

Title :   A Microsegregation Parameter Study of Precipitation in Al-Zn-Mg Alloys.

Descriptive Note : Technical rept.,

Corporate Author : RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF MATERIALS ENGINEERING

Personal Author(s) : Wirsing,Adolf E. ; Judd,Gary

Report Date : DEC 1975

Pagination or Media Count : 23

Abstract : Electron probe microanalysis was used to obtain a statistical microsegregation parameter which describes solute redistribution during the precipitation process in Al-Zn-Mg alloys. Precipitate nucleation and solute diffusion, which depend on the concentration and mobility of vacancies, determine the extent to which redistribution occurs throughout the heat treatment. Solution heat treatment temperature, quench rate, aging temperature and grain size were varied, and the effect of these variations on the distribution of precipitation was measured in terms of the microsegregation parameter. Microsegregation in the initial stages of aging is characterized by apparently independent redistribution of Mg and Zn. This effect may reflect the different solute-vacancy binding energies for these solute elements of Al. As aging proceeds, the alloys exhibit parallel redistribution of Mg and Zn indicating the development of solute partitioning as part of the precipitation process.

Descriptors :   *Aluminum alloys, *Precipitation, *Aging(Materials), Magnesium alloys, Zinc alloys, Nucleation, Segregation(Metallurgy), Microstructure, Electron probes, Grain size, Analysis of variance, Heat treatment, Defects(Materials)

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE