Effect of Milling Time on the Characteristics of Al-2.5 wt% AlN Nanopowders Via Mechanical Alloying Process (Pages 35-40)

Esmaeil Salahi1 and Armin Rajabi2

1Materials and Energy Research Center (MERC) P.O.Box 14155-4777, Karaj-Iran; 2Department of Mechanical and Material Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, UKM, Malaysia

Abstract: Metallic Al-powders with 2.5 wt% AlN were mechanically alloyed for 1, 2.5, 5, 10, 15, and 25 h. Compacts were prepared at a pressure of 750 MPa, and their microhardness values were determined to investigate the effect of milling time on the powders’ morphology, particle size distribution, and work hardening. Analyses of morphology and particle size were conducted using a scanning electron microscope and a laser analyzer, respectively. The Vickers hardness of the powders was evaluated at a 10 g load. The hardness of the samples was measured under multiple applied loads, and the Meyer index was used to express the variation of work hardening. Results showed that the compressibility of the powders is affected by prolonged milling. The density of the milled powder could be influenced by contradictory effective parameters in each densification stage. Thus, considering powder evolutions is necessary when analyzing milled powder behavior.

Keywords: Hardness, Morphology, Nanopowder, Meyer, Particle, Milling.