可降解超细晶镁合金在生物医学中的应用(英文)

Ultra-Fine Grained Degradable Magnesium for Biomedical Applications

通过对工业纯镁以及ZM21合金的性能测试研究了镁合金在可降解生物医学中的应用,讨论了等径角挤压制备超细晶以及温挤压对材料性能的影响。晶粒细化导致合金材料压缩强度明显提高,强烈的初始变形织构导致粗晶镁合金拉伸强度高于压缩。等径角挤压能够减弱织构的影响,使不同合金塑性流变行为获得改变。材料腐蚀性能主要受化学成分、晶粒大小以及先前变形诱导晶格畸变程度的综合影响。等径角挤压细化晶粒、增大晶格缺陷密度在一定程度上制衡了材料的腐蚀性能。同时弥散分布的第二相粒子的增加对于点蚀发展有着积极的作用。

Properties of commercially available purity magnesium and wrought ZM21 Mg alloy were investigated in view of their biodegradable applications. In particular, the opportunities offered by grain size refinement down to the ultra-fine scale achieved by equal channel angular pressing （ECAP） and warm extrusion were discussed and material properties were analyzed. Results show that the grain refinement will lead to a significant improvement in compression strength. The tension strength of the coarse grained alloy is always significantly higher than that measured in compression due to the sharp texture of the starting wrought alloy. ECAP also causes an attenuation of the above texture effects, promoting marked changes in plastic flow behavior. The corrosion behavior of the investigated materials are affected by a combination of microstructural effects such as chemistry, grain size and the extent of lattice distortion inherited from previous processing stages. ECAP leads to refinement of grain size and to increased lattice defect density which apparently produce counterbalancing effects on corrosion performance. The improved dispersion of second-phase particles brings positive effects on development of pitting.