Effect of Thermomechanical Treatment on Microstructure, Mechanical and Corrosion Properties of Mg-XZn-1Mn Alloys as Biomedical Materials

摘要

A thermomechanical treatment process for Mg-XZn-IMn alloys (X = 1,2,3 and 4 wt.-%) was performed to develop their potential use as biomaterials. Controlled hot forging with a reduction of 10 % followed by suitable heat treatment was processed on the alloys. The microstructure, mechanical property and corrosion behavior of the cast and TMT alloys have been investigated in this study. These alloys were characterised by X-ray diffraction analysis, optical microscopy and SEM with EDX. The corrosion behavior was also investigated using immersion and po-tentiodynamic polarization tests. Mechanical properties were also determined. The obtained results indicate that all TMT Mg-XZn-IMn alloys are composed of an a-Mg phase and Mg7Zn3, MgZn2 and AlMn precipitates with very fine microstructures. Some large grains and some non-uniform distributed twins are observed in the microstructure. The tensile strength, yield strength and elongation of TMT alloys are higher than cast alloys except for that the elongation of Z4M after TMT is less than that of the cast one. With increasing Zn content up to 3 wt.-% fine structure and higher mechanical properties are obtained in both alloys. Higher corrosion resistance is shown for Z3M after TMT. In contrast cast Z1M shows a lower corrosion resistance.