Formation Mechanism of Nanostructured (Ni, Fe)₃Al-Al₂O₃Nanocomposite and Its Characterization

Abstract

In this work, preparation of (Ni, Fe) 3 Al-Al 2 O 3 nanocomposite powders by mechanochemical reaction of Ni, Al, and Fe 2 O 3 powder mixture was reported. The phase transformation and microstructural characterization during mechanochemical reaction were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and differential thermal analysis (DTA) techniques. The (Ni, Fe) 3 Al-20 vol% Al 2 O 3 nanocomposite can be synthesized by mechanochemical reaction during ball milling of a stoichiometric starting powder mixture, and hence reaction 4Ni þ 4Al þ Fe 2 O 3 took place after 40 h of milling with a gradual mode. Increasing Ni concentration concurrently with decreasing Fe 2 O 3 concentration decreased the start time of (Ni, Fe) 3 Al formation. The formation mechanism of reaction between starting powder mixture and the effect of milling on this reaction were confirmed by using DTA and XRD.

Consolidated Al/Al2O3Nanocomposites by Equal Channel Angular Pressing and Hot Extrusion

“…In order to overcome this obstacle, several non-conventional fabrication processes were proposed in recent studies. Ultrasound assisted casting [12], disintegrated melt deposition [2], in situ processing [13,14], powder metallurgy (PM) [15][16][17][18][19], and other methods [20,21] have proven to be effective in preparing MMNCs characterized by well-dispersed discrete nanoparticles. Common consolidation techniques used for these materials include hot forging and hot isostatic pressing (HIP) [2].…”