Fascinating microstructural evolution during consolidation and remarkable hardening behaviour of micro alloyed Al-Cu-Ni alloys

Ultrafine B2 NiAl and vacancy ordered phase (Al3Ni2 type) (Cu) evolve during consolidation of mechanically alloyed Al-Cu-Ni alloys without and with micro alloying addition of Zr and or Ti and results in high hardness of the alloys. Al-Cu-(Ni15)-Zr alloy consolidated by spark plasma sintering exhibits a remarkable hardness value of 7.2 GPa. Wide range of hardness values of the alloys indicates a significant effect of composition as well as synthesis route. Hardening behaviour through point defect hardening has been demonstrated in terms of constitutional vacancy concentration as well as solute dislocation interaction. Lattice parameter, bulk density, porosity anddislocation density of the alloys have been measured to understand the hardening mechanism further. TEM analysis and wear behaviour are carried out to justify the phase formation and strengthening mechanism of the alloys, respectively. (c) 2023 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.

Automated summary

Ultrafine B2 NiAl and vacancy ordered phase (Al3Ni2 type) (Cu) form during consolidation of mechanically alloyed Al-Cu-Ni alloys with and without micro alloying addition of Zr and/or Ti, resulting in high hardness. The Al-Cu-(Ni15)-Zr alloy consolidated by spark plasma sintering exhibits a remarkable hardness value of 7.2 GPa. The wide range of hardness values indicates the significant influence of composition and synthesis route. The hardening mechanism is explained through point defect hardening and solute dislocation interaction.