Mwcnt powders

Commercial pure aluminum powder (Merck, Darmstadt, Germany, 99% purity) with an average particle size less than 50 μm and MWCNT powders (Sigma Aldrich, St. Louis, MO, USA, 20–30 nm particle size nm of outer diameter and length of 10 to 30 μm) were used as raw material (Figure 6). The Al-CNT nanocomposites containing 2 wt % multiwalled CNTs (MWCNTs) were synthesized in a combination of ball milling and powder metallurgy route. The MWCNT powders were first dispersed in the pure aluminum matrix in the presence of Stearic acid (2 wt %) using a planetary ball milling machine (PM100, Retsch, Haan, Germany) at room temperature. Stearic acid as a process control agent (PCA) hinders excessive cold welding of the particles during milling process. The ball to powder weight ratio (BPR) of 8:1 was chosen. The powder mixtures were ball milled for different times from 30 min up to 12 h at constant rotational speed of 300 rpm. Nanocomposite powders were then consolidated by cold pressing at a pressure of 150 MPa under argon atmosphere followed by sintering at 530 °C for 45 min under argon atmosphere to obtain sound bulk nanocomposites specimens.