Ismail Özdemir, Sascha Ahrens, Silke Mücklich, Bernhard Wielage
May 5, 2013
Aluminum-copper alloy EN AW 2017 (Al-3.9Cu-0.6% Mn-0.7%Mg) based composite powders reinforced with 5 and 15 vol. % SiC particulates were produced by high energy ball milling (HEM) process. The milling times range between 10 min and 6 h. After milling for a certain time, i.e., 2 h, the cellular structure of CuAl 2 intermetallic particles initially present in the matrix and precipitate at the grain boundaries that were destroyed and distributed along the deformation axis. XRD results clearly showed that the X-ray diffraction peaks of CuAl 2 disappear after 2 h milling time suggesting that the submicrometer sized intermetallic CuAl 2 particles dissolved into the aluminum matrix. This was also confirmed by SEM investigation. During subsequent milling of composite blends (2 h and more) the reinforcement particles were heavily fragmented. Thus they exhibited a significant reduction in size. The results indicate that the particle size of SiC and CuAl 2 was refined greatly after 6 h of high energy ball milling. However, it is clear that the particle size distribution even after the longest period of milling, 6 h, showed no significant narrowing. The crystallite size of the composites was reduced to below 45 nm which was confirmed by X-ray line broadening analysis.