Microstructural and Mechanical Properties of Al‐Based Composites Reinforced with In‐Situ and Ex‐Situ Al₂O₃ Nanoparticles

Abstract

A powder metallurgy route based on high-energy ball milling and powder consolidation by ECAP is used to produce Al-matrix composites reinforced with Al 2 O 3 nanoparticles. The reinforcement is produced in-situ during the milling process and added ex-situ. Ball milling led to the fragmentation of the oxide layer that covers the Al particles and to the formation of very thin Al 2 O 3 dispersoids. Moreover, it was able to break the Al 2 O 3 particle clusters added ex-situ and to embed the oxide in the ductile Al matrix. After powder consolidation by ECAP, the nanocomposites showed an ultra-fine grained and fully dense matrix characterized by uniformly dispersed nanoparticles.

Composite and Nanocomposite Metal Foams

“…Nanoscale reinforcements have been incorporated in several types of matrices to obtain nanocomposite foams, but the number of available literature reports is scarce [ 126 , 127 , 128 , 129 ]. A small addition (usually less than 2 wt.%) of nanoparticles can significantly strengthen the metal matrix, solving the problems of current Al-foams incorporating high loadings (generally above 10 vol.%) of microscale reinforcements required to achieve the desired levels for the mechanical properties (e.g., elastic modulus) and dimensional stability, thus compromising the weight and the toughness of the final composites.…”

Revealing the Influence of SiC Particle Size on the Hot Workability of SiCp/6013 Aluminum Matrix Composites

“…Particle-reinforced aluminum matrix composites (AMC) are widely used and indispensable in aerospace and automotive industries owing to their high specific strength, high specific stiffness, and high wear resistance [ 1 , 2 , 3 ]. Powder metallurgy is generally employed to prepare AMC because it is able to easily optimize the size and content of the reinforcing particles and increase the uniformity of distribution among reinforcing particles [ 4 , 5 , 6 ]. However, these AMCs prepared by powder metallurgy often require further hot working (e.g., hot rolling or extrusion) to reduce defects and increase the density [ 7 , 8 , 9 ].…”

Engineering of strong and hard in-situ Al-Al3Ti nanocomposite via high-energy ball milling and spark plasma sintering

“…Various additives have been used to enhance the mechanical properties of Al-MMCs: Al 2 O 3 [4], TiB 2 [5], TiC [6,7], SiC [8], and BN [9]; carbon nanotubes [10,11], intermetallics and metallic glasses [12][13][14][15]. Reinforcing phases have been introduced into the aluminum matrix by in-situ and ex-situ approaches; for in-situ approaches, the reinforcing phase is formed during processing, for example during casting [16] or thermal treatment [17].…”