Ruixiao Zheng

Fabrication of Nanostructural Aluminum Alloy Powder with Ball Milling Method

The strength of aluminum alloys can be strongly affected by addition of homogeneous dispersed strengthen particles in nanocrystalline matrix. One method to engineer nanocrystalline materials with strengthen particles is mechanical alloying. The aim of this paper is to fabricate aluminum alloy powder with nanostructure using ball milling method. The commercial Al-Mg-Cu alloy powder was milled along with a different proportion of Fe-based alloy powder (produced by argon gas atomization process) under various ball milling conditions (milling time, process control agents and rotation speed). The structure and the thermal stability of the ball milled powder were examined using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). It is revealed that the Al alloy grain size was minish to 26nm with Fe-based alloy homogeneously dispersed in it. Based on the structural observation, the formation behavior of nanostructural in ball milled powder is discussed.

Super High Strength Aluminum Alloy Processed by Mechanical Alloying and Hot Extrusion

Nanostructure strengthened aluminum alloy was prepared by powder metallurgic technology. The rapid solidification Al-Cu-Mg alloy powder was used in this study. To obtain nanostructure, the commercial powder was intensely milled under certain ball milling conditions. The milled powder was compacted first by cold isostatic pressing (CIP) at a compressive pressure of 300MPa, and then extruded at selected temperature for several times to obtain near full density material. Microstructure and mechanical properties of the extruded alloy were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical tests. It is revealed that the compressive strength of extruded alloy is higher than 800MPa. The strengthening mechanism associated with the nanostructure is discussed.