Gamma Phase Precipitation Processes in Quenched  Phase Cu-Zn-Al Alloys at an Electron Concentration of 1.53.

A. CONDO; P. ARNEODO LAROCHETTE; A. TOLLEY

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

ELSEVIER SCIENCE SA

Año: 2002 vol. 328 p. 190 - 195

0921-5093

The precipitation of the phase in quenched Cu–Zn–Al alloys at an electron concentration (e/a) of 1.53 was studied in detailby optical, scanning and transmission electron microscopy. Two precipitation processes were found: (i) a dendritic precipitationin cuboidal regions of 10–40 m was found at low quenching velocities, below about 500 K s−1, but was suppressed by increasingthe quenching rate to 1150 K s−1; (ii) small spheroidal precipitates with -brass structure, typically 10 nm in size, were observedeven after quenching at the highest velocities. They formed on first- and second-neighbour antiphase boundaries. The latterprocess was found to occur more readily than in Cu–Zn–Al alloys at e/a=1.48. The hysteresis of the spontaneous martensitictransformation was not appreciably affected by the presence of the latter precipitates. © 2002 Elsevier Science B.V. All rightsreserved.