Selective Laser Melting of Metal Matrix Composites and Alloys

Selective laser melting (SLM) is a layer-wise additive manufacturing technique in which a high-power laser selectively fuses metallic powders to build components with intricate geometries and tailored microstructures. When applied to metal matrix composites (MMCs) and advanced alloys, SLM affords unprecedented control over reinforcement distribution, intermetallic phase formation and porosity minimisation. By varying laser power, scan speed and hatch spacing, it is possible to refine grain size, promote in situ intermetallic formation and achieve near-full density in parts that combine high strength, wear resistance and reduced weight. MMCs produced by SLM typically incorporate ceramic particles or intermetallic dispersoids that enhance hardness and modulus, while novel alloy designs introduce nanoscale medium-entropy lamellae to balance strength and ductility. Challenges include residual stress management, anisotropic mechanical behaviour and thermo-physical instabilities such as cracking or keyholing. Nonetheless, the capacity to integrate multiple reinforcement types and to fabricate complex lattice and functionally graded structures has driven rapid uptake in aerospace, automotive and biomedical sectors, where bespoke high-performance components are in growing demand.

Research from Nature Portfolio

Recent studies have demonstrated that custom aluminium alloys with nanoscale intermetallic lamellae can be produced by SLM to yield unprecedented combinations of strength and plasticity. One investigation created an Al-Ti-Fe-Co-Ni medium-entropy alloy, in which heterogeneous intermetallic phases formed during rapid solidification. The resulting parts exhibited compressive strengths exceeding 700 MPa, plastic strains above 10 % and local flow stresses approaching 900 MPa, attributed to synergistic dislocation activity in matrix and intermetallic regions. Complementary work has shown that aluminium powders pre-alloyed with ceramic nanoparticles can be laser-melted layer by layer to produce nanocomposite structures. Enhanced laser absorption by the nanoparticle-laden feedstock yields ultrafine grains and a uniform particle dispersion, achieving yield strengths of up to 1000 MPa, retained ductility over 10 % and thermal stability to 400 °C.

Selective Laser Melting of Metal Matrix Composites and Alloys publication trend

The graph below shows the total number of articles in selective laser melting of metal matrix composites and alloys across all publications each year (not limited to Nature Index journals).

Technical terms

Selective laser melting (SLM): An additive manufacturing process in which a laser beam selectively fuses successive layers of metal powder to build three-dimensional parts.

Metal matrix composite (MMC): A material system composed of a continuous metallic matrix reinforced by dispersed ceramic or intermetallic particles to improve mechanical and thermal properties.

Laser powder bed fusion (LPBF): A subclass of SLM involving the spreading of a thin powder layer followed by laser melting; often used interchangeably with SLM.

Intermetallic compound: A chemically ordered phase formed between two or more metallic elements, often exhibiting high hardness and brittleness.

Porosity: The presence of voids or unmolten regions within a manufactured part, which can degrade mechanical performance and fatigue resistance.

References

1. Additive manufacturing SiC-reinforced maraging steel: Parameter optimisation, microstructure and properties. Advanced Powder Materials (2023).
2. An overview of additively manufactured metal matrix composites: preparation, performance, and challenge. International Journal of Extreme Manufacturing (2024).
3. Additive manufacturing of an ultrastrong, deformable Al alloy with nanoscale intermetallics. Nature Communications (2024).
4. Aluminum with dispersed nanoparticles by laser additive manufacturing. Nature Communications (2019).
5. Laser powder bed fusion of AA7075 alloy: Influence of process parameters on porosity and hot cracking. Additive Manufacturing (2020).