Microstructure evolution and strengthening mechanisms of a high-performance TiN-reinforced Al-Mn-Mg-Sc-Zr alloy processed by laser powder bed fusion

•Near fully dense samples with porosity less than 0.1% are obtained in the L-PBF TiN reinforced Al-Mn-Mg-Sc-Zr alloy.•Ultrahigh tensile yield strength over 580 MPa is achieved at the as-built TiN/Al-Mn-Mg-Sc-Zr composite.•The addition of TiN nanoparticles effectively promotes the columnar-to-equiaxed grains transition and the composite samples show ultrafine microstructure.•The strengthening mechanisms is mainly attributed to the ultrafine grains, ultimate solid solution of alloying elements, and the high volume density of Al3(Ti,Sc,Zr) nanoprecipitates.