Effect of Ni and Si alloying elements on the phase evolution, mechanical properties, tribological behaviour of Al-Cu alloys

The present study aims to understand the solidification pathways of novel Al-rich multicomponent alloys with ultrafine eutectic with micron-scale dendrite. Four eutectic alloys Al-Cu-X (X = Ni1.5, Si5, Ni1.5 and Si5) have been designed with the help of thermodynamic simulation using the thermo-calc software, followed by synthesis by solidification processing technique. The microstructure of the studied alloys reveals the presence of dendrite phases and eutectic phase mixtures, bimodal eutectics, peritectic phase and ternary eutectics mixture (L -> alpha-Al + Al7Cu4Ni + beta-Si). Based on these results a quasi-peritectic reaction (L + Al7Cu4Ni -> alpha-Al + Al2Cu) has been proposed for AlCuNi1.5 alloy which has confirmed with the DSC results. With the addition of Ni and Si, the tensile strength and hardness of these alloys increases to 336 MPa and 188.84 HV from 231 MPa and 134.2 HV respectively. The AlCuNi1.5Si5 alloy have better wear resistance (3.40 cm 3) as compared to other alloys.

Automated summary

The present study aims to understand the solidification pathways of novel Al-rich multicomponent alloys with ultrafine eutectic with micron-scale dendrite. Four eutectic alloys Al-Cu-X (X = Ni1.5, Si5, Ni1.5 and Si5) have been designed with the help of thermodynamic simulation using the thermo-calc software, followed by synthesis by solidification processing technique. The microstructure of the studied alloys reveals the presence of dendrite phases and eutectic phase mixtures, bimodal eutectics, peritectic phase and ternary eutectics mixture (L -> alpha-Al + Al7Cu4Ni + beta-Si). Based on these results a quasi-peritectic reaction (L + Al7Cu4Ni -> alpha-Al + Al2Cu) has been proposed for AlCuNi1.5 alloy which has confirmed with the DSC results. With the addition of Ni and Si, the tensile strength and hardness of these alloys increases to 336 MPa and 188.84 HV from 231 MPa and 134.2 HV respectively. The AlCuNi1.5Si5 alloy have better wear resistance (3.40 cm3) as compared to other alloys.