Substitution of Zn for Cu in Mg-Y-Zn alloys designed for fracturing ball

The microstructure, mechanical properties and degradation behaviour of Mg95Y3Zn2 (MYZ), Mg95Y3Zn1Cu1 (MYZC), and Mg95Y3Cu2 (MYC) (at.-%) alloys have been studied. All the alloys mainly contain & alpha;-Mg matrix and LPSO phase. By substituting Zn for Cu, the composition of the LPSO phase transformed from Mg-Y-Zn to Mg-Y-Zn-Cu, and then to Mg-Y-Cu. The ultimate compressive strength is 227, 231 and 238 MPa, respectively. The MYC alloy exhibited much higher degradation rate than MYZC and MYZ alloys. The strong galvanic coupling effect between LPSO phase and the matrix, the grain size refinement and the weak protection from the corrosion product layer are responsible for the high degradation rate. It is suggested that the newly developed MYC alloy is promising for fracturing ball application.

Automated summary

The microstructure, mechanical properties, and degradation behavior of Mg95Y3Zn2 (MYZ), Mg95Y3Zn1Cu1 (MYZC), and Mg95Y3Cu2 (MYC) alloys were studied. All alloys consisted of an α-Mg matrix and LPSO phase. By substituting Zn with Cu, the composition of the LPSO phase changed from Mg-Y-Zn to Mg-Y-Zn-Cu, and then to Mg-Y-Cu. The ultimate compressive strength for MYZ, MYZC, and MYC alloys were 227, 231, and 238 MPa, respectively. The MYC alloy exhibited a higher degradation rate due to the galvanic coupling effect, grain size refinement, and weak protection from corrosion product layer. The newly developed MYC alloy shows promise for fracturing ball applications.