Abstract
The production of high hardness and thermally stable nanocrystalline aluminium composites is described. Al powder was milled at room temperature in an ammonia flow for a period of less than 5 h. NH3dissociation during milling provokes the absorption, at a high rate, of nitrogen into aluminium, hardening it by forming a solid solution. Controlled amounts of AlN and Al5O6N are formed during the subsequent sintering of milled powders for consolidation. The pinning action of these abundant dispersoids highly restrains aluminium grain growth during heating. The mean size of the Al grains remains below 45 nm and even after the milled powder is sintered at 650°C for 1 h.
Highlights
Nanostructured materials are promising materials that offer new opportunities for substantially improving the standard of living
This paper describes a new and simple method to obtain aluminium-based nanostructured components reinforced by self-forming nanometric aluminium nitride (AlN)
The curve of the MA A 500 powders (Figure 1(b)) shows that, contrary to that expected for a ductile powder such as aluminium, the particle size decreases from its initial value
Summary
Nanostructured materials are promising materials that offer new opportunities for substantially improving the standard of living. The most common processing methods for the production of nanocrystalline materials include inert gas condensation, chemical reaction methods, electrodeposition, severe plastic deformation, and mechanical milling [9, 10]. The latter, called high-energy milling or mechanical alloying, is considered one of the main techniques in this regard [11, 12]. One of the main challenges towards achieving a homogeneous distribution of a nanometric ceramic phase in a metal matrix is avoiding agglomeration of the reinforcement particles [18]
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