Effect of Cu Content on Ageing Behavior for AA3104-H19 Can Body Sheet

摘要

AA3104 ingots with different Cu content (O.lwt.%, 0.2wt.% and 0.3wt.%) were prepared by DC casting, and then the ingots were processed to 0.26mm sheets with the method of making AA3104 can be body sheet. The AA3104-H19 sheets were aged at 180°C and the aging strengthen effect were found in the 0.2wt.%Cu and 0.3wt.%Cu alloys. Optical micrograph (OM), X-ray diffraction, high resolution transmission electron microscope were used on the sheets after different ageing time. Rod like coherency precipitates with the length about 5-10nm and the thickness about 2-3nm which were parallel to the [111] plane of the matrix was precipitated at peak aging (180°C-2h). According to the result of the thermodynamic phase diagram calculation, the precipitates should be S-Al_2CuMg phase, but the structure of the precipitates were different from the precipitates reported in 2XXX alloy.