Journal of Minerals & Mateials Characterization & Engineering , Vol. 10, No.6, pp.507-515, 2011 jmmce.org Printed in the USA. All rights reserved 507 A Comparative Study on the Milling Speed for the Synthesis of Nano- Structured Al 6063 Alloy Powder by Mechanical Alloying Hafeez Ahamed and V. Senthil Kumar * Department of Production Engineering, National Institute of Technology, Thiruchirappalli- 620015, India. * Corresponding Author: vskumar@nitt.edu ABSTRACT The present article reports on characterization studies performed on amorphized nano- structured Al 6063 alloy powder synthesized by mechanical alloying (MA). The as-milled powder was characterized by X-ray diffraction (XRD) for investigating the development of crystallite nature and determining the different phases of the materials present, scanning electron microscope (SEM) was used for in depth morphological study and High Resolution-transmission electron microscope (HR-TEM) was employed to ensure the development of a nano-structured nature of the Al 6063 matrix. In the present work alloyed powder was milled for 20 h and 40 h at 300 rpm; and 20 h at 700 rpm in a hardened stainless steel medium. Using Williamson-Hall equation; crystallite size, lattice strain and lattice parameter of Al 6063 nanostructure alloy powder was estimated with broadening of XRD peaks. XRD results showed that the crystallite size of Al 6063 alloy powder reached 32 and 53 nm after 20 h at 700 rpm and 40 h at 300 rpm respectively. Keywords: Nano-structured; Al 6063; Synthesis. 1. INTRODUCTION Nano-structured metals and alloys, with average and range of grain sizes typically smaller than 100 nm, have been the subject of considerable research in recent years. Such interest has been spurred by progress in the processing of materials and by advances in characterization techniques for complete understanding of the structural and physical properties of the recent advanced metallic nano-materials [1].In metallurgical research, X-ray diffraction, scanning electron