HREM and HAADF Imaging of Al3(Sc, Zr) Intermetallic Phase in Al Alloys.

TOLLEY, ALFREDO JUAN; VELIMIR RADMILOVIC,; ULRICH DAHMEN,

Hawai

Congreso; Microscopy and Microanalysis 2005; 2005

Microscopy Society of America

Core-shell particle structures have received considerable recent attention because it has been demonstrated that the core properties can be significantly altered by the shell [[1],[2]]. The majority of research in this field has concentrated on free standing particle systems with or without ordering in two or three dimensions [1,2]. Recent work on Al-Sc-Zr alloys [[3]] has shown that a core-shell structure may also be responsible for the modification of properties in a precipitate-hardened alloy system. It was demonstrated that the precipitates contained Sc and Zr, but that the distribution of Zr was not homogeneous. Instead, a Zr rich shell surrounded an Al3Sc core. In this report we use the compositional sensitivity of Z-contrast imaging to show that the addition of Zr to an Al-Sc alloy leads to formation of a complex Al3(Sc,Zr) core/shell structure. [[1]] B.T. Holland, C.A. Blanford and A. Stein, Science 281 (1998) 538. [[2]] F. Caruso, R.A. Caruso and H. Möhwald, Science 282 (1998) 1111. [[3]] A. Tolley, V. Radmilovic and U. Dahmen, Scripta Mater. 52 (2005) 621.