The effect of in-situ formed TiB2 particles on microstructural and mechanical properties of laser melted copper alloy

Abstract Mixed Cu-4Ti (wt.%) and Cu-1.4B (wt.%) powders were separately mechanically alloyed and then homogenized. The obtained powder was laser melted by pulsed Nd:YAG laser and heat treated at 900 °C for 10 h in argon. 3D compacts were characterized by means of digital camera images, optical microscopy and scanning electron microscopy. Microstructure after laser melting varies regionally due to mixing of two different mechanically alloyed powders and contains in-situ formed microparticles of primary TiB 2 . Formation of secondary TiB 2 nanoparticles was possible only after high temperature heat treatment (900 °C, for 10 h) as concluded from X-ray diffraction analysis, chemical analysis, and microhardness tests of laser melted and heat treated parts. Copper matrix was strengthened to a significantly higher extent after the formation of secondary TiB 2 nanoparticles.