Effect of SiC Nanoparticles Content and Milling Time on the Characteristics of Al/SiC Nanocomposite Powders Produced Via Mechanical Milling

摘要

In the present study high energy ball milling was utilized to produce aluminum (Al-6061) matrix nanocomposite powders reinforced with nano silicon carbide (SiC) particles. The starting materials containing different percentages (1,3 or 5 wt.%) of nano SiC particles (25-50 nm) and Al (38-63 μm) were co-milled for different times (16, 20, 24 h) to achieve nanocomposite powders. The crystal size of powders were evaluated by quantitative XRD analysis. Laser particle size analysis was used to evaluate the size of powders during milling. The microstructure of powders and their microhardness values were evaluated by Scanning Electron Microscopy (SEM) and a microhardness tester respectively. The results indicated that the crystal size of the matrix alloy decreased by milling time. The increased SiC content up to 3% resulted in increased microhardness of the powders. However, further increase of SiC to 5% resulted in decreased microhardness due to agglomeration. It was concluded that the maximum microhardness together with a uniform distribution of SiC particles within the matrix alloy was obtained after 20 h milling of powder mixture containing 3% of SiC nanoparticles.