挤压态Mg99.2Ca0.6Mn0.2合金的力学行为及腐蚀性能研究

Mechanical behavior and corrosion properties of hot extruded Mg99.2Ca0.6Mn0.2 alloy

摘要:

研究了挤压态Mg99.2Ca0.6Mn0.2镁合金的位伸行为和压缩行为，探讨了合金在不同PH值的SBF模拟体液中的电化学极化曲线和阻抗谱，以评定合金的腐蚀性能，为镁合金植入材料的制备提供依据。结果表明：挤压态Mg99.2Ca0.6Mn0.2合金表现出准解理断裂的特征，抗拉强度、屈服强度、延伸率分别为279 MPa、251 MPa和11%，抗压强度为330 MPa。腐蚀介质的PH值对合金的腐蚀性能有显著影响。随着腐蚀介质PH值升高，阻抗谱弧半径大幅度增大，合金的腐蚀电位升高，腐蚀电流密度降低，合金的腐蚀速率明显下降。在阻抗谱的低频端出现了一个时间常数。PH值为7.2和10的SBF溶液中的瞬时腐蚀速率分别为4.1 mm/a和0.2 mm/a。

Abstract:

The tensile and compression behavior of hot extruded Mg99.2Ca0.6Mn0.2 (at%) alloy were tested, the cyclic polarization curves and impedance spectroscopy of the alloy soaked in SBF solutions with various pH values were measured by electrochemical method so that the corrosion properties of the alloy can be evaluated and the experimental foundations for preparation of magnesium implant materials is provided. The results show that the tensile failure of the alloy appears to be characteristic of quasi-cleavage fracture, the tensile strength, yield strength, compressive strength and elongation are 279 MPa, 251 MPa, 330 MPa and 11% at room temperature, respectively. The PH value of the solution has prominent effect on corrosion property. As the PH value increases, the arc radius of impedance spectroscopy and corrosion potentials increase remarkably, whereas the corrosion current density decreases, and thus the corrosion resistance of the alloy is strengthened. There is only one time constant which appears in low frequency in phase angle plot. The corrosion rate can be significantly reduced by increasing PH value of the solution. The instantaneous corrosion rates of the alloy immersed in the solutions with PH value of 7.2 and 10.0 are 4.1 mm/a and 0.2 mm/a after, respectively.