Effects of volume fraction of Ni-containing LPSO phase on mechanical and corrosion properties of Mg-Gd-Ni alloys

Mg-Gd-Ni alloys with same Gd/Ni mole ratios but different volume fraction of Ni-containing LPSO phase were prepared. The effects of the volume fraction of Ni-containing LPSO phase on the mechanical and corrosion properties of Mg-Gd-Ni alloys were systematically investigated. It was found that the strength was remarkably enhanced but the plasticity was decreased with the increase of the volume fraction of Ni-containing LPSO phase. The electro-potential distribution characteristic shows that the Ni-containing LPSO phase had a lower electro-potential than the Mg matrix, which was related to the existence of Ni in LPSO phase. Consequently, Ni-containing LPSO phase was preferentially eroded during micro-galvanic corrosion. High volume fraction LPSO phases accelerated the corrosion rate of Mg-Gd-Ni alloy. The detailed corrosion mechanisms were discussed in the present study.