The Combined Effect of Sn Additions and Ultrasonic Vibration Treatment on Microstructure, Mechanical Properties, and Corrosion Resistance of Mg-3 wt% Zn Biodegradable Alloy for Human Bone Fixation
摘要
The effect of the additions of tin (Sn) loadings up to 3 wt% has been studied on the microstructural, mechanical, and corrosion properties of the investigated Mg-3 wt% Zn alloy “MZ3 alloy.” Furthermore, the combined effect of the optimum addition of Sn and ultrasonic vibration (USV) treatment has also been investigated. The behavior of the corrosion has been determined by the potentiodynamic polarization measurements using a simulated body fluid solution. It has been found that the addition of 1 wt% Sn led to significantly reduction in grain size of the primary α-Mg phase in the investigated alloy from 125 to 47 µm. The dual effect of USV and 1 wt%Sn addition resulted in a finer equiaxed α-Mg grains down to 33 µm. The improvement in mechanical characteristics has been also achieved. The Vickers hardness, ultimate tensile strength and elongation % of the modified alloy increased from 53 HV, 157 MPa and 2% in the investigated alloy without Sn additions to 67 HV, 174 MPa and 6% after 1 wt% Sn addition “MZT31 alloy,” respectively. Furthermore, the properties of MZT31 alloy significantly exceeded to 72 HV, 187 MPa and 9.2% after the application of USV treatment. It was concluded that the uniform distribution of SnO/SnO2 phases together with the surface layer of MZT31 and MZT31 (as-USV) alloys enhanced the corrosion resistance according to significantly reduction in grain size of the cast structure.