Effect of in-situ TiB2 particles on microstructure and mechanical properties of Al–Fe–Ni manufactured by selective laser melting

Abstract

To simultaneously enhance the strength and ductility of novel heat-resistant Al–Fe–Ni alloy manufactured by selective laser melting (SLM), nano-TiB2 particles are introduced to break the strength-ductility trade-off. In this study, in-situ TiB2 decorated Al–Fe–Ni composite and Al–Fe–Ni base alloy have been successfully fabricated by SLM to investigate the effects of TiB2 particles on the microstructure and mechanical properties. The results showed that broader SLM process windows and higher relative densities (better SLM processability) were achieved in the composite. The introduced TiB2 particles transformed the large elongated grains with a strong {100} texture in the Al–Fe–Ni alloy to fine equiaxed grains with random orientation in the TiB2/Al–Fe–Ni composite. The morphology and distribution of Al9FeNi phases were also changed due to the existence of particles. The stress-strain curves obtained from tensile tests showed that the strength and ductility were improved simultaneously in the composite compared with those in the alloy. The underlying mechanisms of strengthening and enhancing ductility are preliminarily elucidated.