Microstructure and mechanical properties of extruded Mg-6Al-2X (X = Cu/Ni/Fe) alloy used degradable bridge plugs

Magnesium alloys have recently received much attention as fracturing tools for unconventional oil and gas development. It is well known that increasing micro-galvanic corrosion by doping elements in magnesium alloys is an effective method to get highly degradable alloys. The study aimed to evaluate the effect of different doping elements (i.e., copper, nickel and iron) on the mechanical and degradation behavior of hot extruded magnesium alloys. Nickel-containing alloys show high degradability and mechanical properties compared to the other two alloys. Specifically, the second phase of nickel-containing alloys has a dotted distribution, and this distribution favors the diffusion of corrosion. Meanwhile, the addition of nickel improves the mechanical properties of the alloy with a compressive strength of 430.6 MPa. In addition, based on the first principles and phase diagram simulations. With the addition of nickel, the compounds formed in the alloy act as drivers for the improved degradation properties, resulting in a corrosion rate of 1638.14 mm/year at 93 °C. Therefore, nickel-containing alloys that have been hot extruded show wide application prospects in the field of oil and gas extraction.

Graphical abstract

The influence of Cu/Ni/Fe elements on the microstructure, mechanical properties, and corrosion properties of Mg-6Al (wt. %) alloy was investigated using electrochemical tests, hydrogen evolution, and weight loss measurement.