Abstract
Aluminum matrix composites (AMC) are of great interest and importance as high-performance materials with enhanced mechanical properties. Al2O3 is a commonly used reinforcement in AMCs fabricated by means of various technological methods, including casting and sintering. Selective laser melting (SLM) is a suitable modern method of the fabrication of net-shape fully dense parts from AMC with alumina. The main results, achievements, and difficulties of SLM applied to AMCs with alumina are discussed in this review and compared with conventional methods. It was shown that the initial powder preparation, namely the particle size distribution, sphericity, and thorough mixing, affected the final microstructure and properties of SLMed materials drastically. The distribution of reinforcing particles tends to consolidate the near-melting pool-edges process because of pushing by the liquid–solid interface during the solidification process that is a common problem of various fabrication methods. The achievement of an homogeneous distribution was shown to be possible through both the thorough mixing of the initial powders and the precise optimization of SLM parameters. The strength of the AMCs fabricated by the SLM method was relatively low compared with materials produced by conventional methods, while for superior relative densities of more than 99%, hardness and tribological properties were obtained, making SLM a promising method for the Al-based matrix composites with Al2O3.
Highlights
The current review aims to show the main achievements in this direction, to discuss the difficulties and possible ways to overcome them, and to compare Selective laser melting (SLM) with conventional methods applied to
Returning to the temperature of the molten pool, there are some studies about the SLM/SLS of the Al2 O3 ceramic [102,103] that showed the LED values normalized to the square of the laser spot to be of the same order as those for Al-based materials melting, making the consideration about the state of alumina particles within the melting pool highly controversial
Aluminum matrix composites (AMC) fabricated by some conventional technologies [32,110], though it exceeds some other results obtained on Al-Al2 O3 composites [5,111]
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The aluminum alloy composites can be produced via various synthesis approaches [2,30], involving casting [31,32] and stir casting [5,33], which are characterized by a strong particle bonding, matrix structure control simplicity, and near-net-shape, as well as being one of the most economical [2,30,34,35,36] These technological routes imply the addition of reinforcing particles into a molten matrix, and the main problems associated with casting processes are the achievements of sufficient wettability and a reinforcement phase heterogeneous distribution [33]. The mixing of the matrix and ceramic particles in the solid state within powder metallurgy methods with subsequent sintering is considered the most widely used technique for aluminum alloy composites [4,41,42] It allows the achievement of a better microstructure control with a more homogeneous reinforcement distribution. Scattered information is collected within the present review to help researchers in this field achieve better mechanical behavior results of Al-Al2 O3 compounds fabricated via SLM
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