The corrosion behavior and mechanical properties of degradable Mg–Li alloys regulated by high-potential and strengthened LPSO phases

The impact of degradable tools on the efficiency of petroleum fracturing is significant, making the development of high-performance degradable tools crucial. As a high-potential strengthening phase, LPSO significantly affects the microstructure and properties of Mg-Li alloys. The increased amount of high-potential LPSO phases intensifies the galvanic coupling with the Mg-Li matrix, while the disordered lamellar LPSO structures within grains further promote corrosion propagation. The Mg8Li5Gd1.25Ni alloy containing the highest amount of LPSO exhibits the most pronounced effects of galvanic corrosion and the highest corrosion rate. Although the blocky LPSO phase slightly impedes corrosion propagation, its overall influence remains limited. Additionally, the increase in LPSO content enhances the tensile strength of the cast Mg-Li alloys from 112 MPa to 143 MPa, while achieving an elongation rate of 37%, mainly due to grain refinement and second-phase strengthening, where uniformly distributed LPSO and deformation kinks enhance strength and plasticity. • Fragmented LPSO increases galvanic sites and accelerates Mg–Li alloy degradation. • LPSO refines grains and enhances strength and plasticity through load transfer. • LPSO improves the strength-plasticity synergy and controlled degradability.