Adjustable corrosion and mechanical properties of Mg-Zn-Ca-Ni alloys for fracturing materials

Abstract

Two sets of alloys, Mg-Zn-Ca-xNi (0 ≤ x ≤ 5), have been developed with tunable corrosion and mechanical properties, optimized for fracturing materials. High-zinc artificial aged (T6) Mg-12Zn-0.5Ca-xNi (0 ≤ x ≤ 5) series, featuring a straightforward preparation method and the potential for manufacturing large-scale components, exhibit notable corrosion rates up to 29 mg cm⁻² h⁻¹ at 25 °C and 643 mg cm⁻² h⁻¹ at 93 °C. The high corrosion rate is primary due to the Ni–containing second phases, which intensify the galvanic corrosion that overwhelms their corrosion barrier effect. Low-zinc rolled Mg-1.5Zn-0.2Ca-xNi (0 ≤ x ≤ 5) series, characterizing excellent deformability with an elongation to failure of ∼26 %, present accelerated corrosion rates up to 34 mg cm⁻² h⁻¹ at 25 °C and 942 mg cm⁻² h⁻¹ at 93 °C. The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series. Additionally, Mg-Zn-Ca-xNi (0 ≤ x ≤ 5) alloys exhibit tunable ultimate tensile strengths ranging from ∼190 to ∼237 MPa, depending on their specific composition. The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-xNi (0 ≤ x ≤ 5) alloys suitable for fracturing materials.