Enhancement of Mechanical Strength and Degradation Rate of Mg-5Al Alloy by Fe Addition via SPS Rapid Densification for Fracturing Applications

With surging demand for oil and gas resources, staged fracturing is becoming extremely important, and fracturing material is the key factor in exploration. Recently developed Mg-Al alloys cannot simultaneously achieve high strength and rapid degradation, limiting their widespread application in the exploration. To address this issue, this study utilized the rapid densification technology of spark plasma sintering (SPS) to sinter Mg, Al, and Fe powders at a ratio of Mg-5Al-Fe (0, 2, 4, 6 wt.%) under a temperature of 510 °C and a pressure of 35 MPa for 800 s. And this study conducted investigations on the microstructure, mechanical strength and degradation rate of the alloy through scanning electron microscope, hardness and compression tests, as well as immersion experiments. The results indicated that SPS enabled rapid powders densification and grain refinement, and the addition of Fe particles formed a second-phase strengthening which could block dislocation, thereby increasing mechanical strength. The ultimate compressive strength (UCS) was increased from 189.37 ± 6.12 MPa for Mg-5Al to 421.21 ± 12.31 MPa for Mg-5Al-6Fe. Furthermore, the addition of Fe accelerated the degradation rate, with the Mg-5Al-6Fe alloys reaching 45.26 ± 2.6 mm/year. Meanwhile, the alloys also had a low density of 1.38 ± 0.027–1.53 ± 0.030 g/cm3, which could effectively reduce the pumping energy consumption of fracturing fluids. These characteristics met the core requirements of degradable fracturing balls, showing the great potential of Mg-5Al-Fe alloys for staged fracturing.