Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7970569 | Materials Characterization | 2015 | 34 Pages |
Abstract
Although they are among the most important precipitation-hardened materials for industry applications, the high-strength AlZnMg(Cu) alloys have thus far not yet been understood adequately about their underlying precipitation scenarios in relation with the properties. This is partly due to the fact that the structures of a number of different precipitates involved in the alloys are unknown, and partly due to the complexity that the precipitation behaviors of the alloys may be closely related to the alloy's composition. In Part I of the present study, we have determined all the unknown precipitate structures in the alloys. Here in Part II, using atomic-resolution electron microscopy in association with the first principles energy calculations, we further studied and correlated the phase/structure transformation/evolution among these hardening precipitates in relation with the alloy's composition. It is shown that there are actually two coexisting classes of hardening precipitates in these alloys: the first class includes the ηâ²-precipitates and their early-stage Guinier-Preston (GP-ηâ²) zones; the second class includes the precursors of the equilibrium η-phase (referred to ηp, or η-precursor) and their early-stage Guinier-Preston (GP-ηp) zones. The two coexisting classes of precipitates correspond to two precipitation scenarios.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
J.Z. Liu, J.H. Chen, Z.R. Liu, C.L. Wu,