A High-Strain-Rate Superplasticity of the Al-Mg-Si-Zr-Sc Alloy with Ni Addition

The current study analyzed the effect of Ni content on the microstructure and superplastic deformation behavior of the Al-Mg-Si-Cu-based alloy doped with small additions of Sc and Zr. The superplasticity was observed in the studied alloys due to a bimodal particle size distribution. The coarse particles of eutectic origin Al3Ni and Mg2Si phases with a total volume fraction of 4.0-8.0% and a mean size of 1.4-1.6 mu m provided the particles with a stimulated nucleation effect. The L1(2)- structured nanoscale dispersoids of Sc- and Zr-bearing phase inhibited recrystallization and grain growth due to a strong Zener pinning effect. The positive effect of Ni on the superplasticity was revealed and confirmed by a high-temperature tensile test in a wide strain rate and temperature limits. In the alloy with 4 wt.% Ni, the elongation-to-failure of 350-520% was observed at 460 degrees C, in a strain rate range of 2 x 10(-3)-5 x 10(-2) s(-1).

Automated summary

The addition of Ni in the Al-Mg-Si-Cu-based alloy was found to enhance superplasticity, improve grain morphology and distribution, and enhance elongation-to-failure under high temperature and large strain rate.