Fabrication of Aluminum/Aluminum Nitride Composites by Reactive Mechanical Alloying

Abstract

Various reactions and the in-situ formation of new phases can occur during the mechanical alloying process. In the present study, Al powders were strengthened by AlN, using the in-situ processing technique during mechanical alloying. Differential thermal analysis and X-ray diffraction studies were carried out in order to examine the formation behavior of AlN. It was found that the precursors of AlN were formed in the Al powders and transformed to AlN at temperatures above 600oC. The hot extrusion process was utilized to consolidate the composite powders. The composite powders were canned in an Al can and then extruded at elevated temperatures. The microstructure of the extrusions was examined by SEM and TEM. In order to investigate the mechanical properties of the extrusions, compression tests and hardness measurements were carried out. It was found that the mechanical properties and the thermal stability of the Al/AlN composites were significantly greater than those of conventional Al matrix composites.

Synergetic effect of milling speed and duration on particle morphology and mechanical properties of nanocrystalline Al matrix containing SiC

“…Generally, the final performance of the AMCs depends on the volume fraction, size and dispersion of reinforcements. High-energy ball milling is a convenient method and is being used for good dispersion of micro/nano reinforcements with Al matrix [8][9][10][11][12][13][14][15], where a higher milling speed is used for mechanical alloying [16]. In addition, plastic deformation is carried out with Al to form a nanocrystalline structure during ball milling.…”

Synergistic strengthening of aluminum with SiC by grain refinement and dispersion hardening

“…Therefore, the degree of SiC p dispersion, which can be significantly enhanced during the ball-milling process, is one of the most crucial factors determining the mechanical properties of the composites. 22,23 Numerous studies have employed ball milling to adequately disperse the reinforcements with Al matrix [24][25][26][27][28][29][30][31] and develop a nanocrystalline Al matrix. In addition, a higher milling speed is employed for the mechanical alloying of various constituent metal powders and ceramics.…”

“…Numerous studies have employed ball milling to adequately disperse the reinforcements with Al matrix 24–31 and develop a nanocrystalline Al matrix. In addition, a higher milling speed is employed for the mechanical alloying of various constituent metal powders and ceramics 6 .…”