The microstructural revolution of Al-10%Al₃Mg₂ nanocomposite during mechanical milling

Abstract

In this study, pure Al and Mg were used to produce Al₃Mg₂ intermetallic compound. Then, Al₃Mg₂ alloy ingot was milled in an attrition ball mill to obtain fine Al₃Mg₂ powder. Al–10 wt. %Al₃Mg₂ nanocomposite was fabricated at different milling times (0–20 h). The effect of milling time on the properties of the obtained powders was studied. X-ray diffraction analysis was used to investigate phase composition and crystal size of the milled powders. Phase identification and the microstructure of the milled powders were investigated using field emission scanning electron microscopy as well as energy-dispersive spectrometer. The results revealed that the size of Al₃Mg₂ powders reduces significantly with milling time (<100 nm) with noticeable ultrafine grains of Al matrix. Uniform distribution of nano-sized Al₃Mg₂ particles in the aluminium matrix was also achieved with increasing milling time. Further, the results revealed that the crystallite size of nanocomposite powders decrease with increasing milling time, while saved lattice strain increases seriously. The mechanism of milling in the current system was specified as ductile–brittle type. It was concluded that the brittle particles of Al₃Mg₂ act as one of milling agent and so the presence of them could reduce the particle size of Al matrix, effectively.

Keywords:

• Nanocomposite
• mechanical milling
• Al₃Mg₂
• crystallite size