Fretting Fatigue Behavior of Amorphous Alloy in Simulated Body Fluid

采用zr基块状非晶合金在模拟体液中进行了微动疲劳试验，研究了其微动疲劳行为。通过对断口表面的SEM观察和试样表面微动区域的XPS分析，比较了试样在空气和模拟体液中的微动疲劳极限，探讨了微动疲劳裂纹的形核机制。研究了zr基块状非晶合金在不同模拟体液中的腐蚀行为。所得结果如下：1) zr基块状非晶合金的抗拉强度与纯Ti相近。非晶态合金在模拟体液中的微动疲劳强度高于空气中，而Ti-6Al-4V在模拟体液中的微动疲劳强度低于空气中。2)环境对zr基块状非晶合金微动疲劳强度的影响可以解释为：SEM观察表明，空气和模拟体液中试样表面微动区形态不同，模拟体液中微动损伤是在微动垫接触区域内均匀诱导的，而空气中则是局部诱导的。因此，在空气中局部诱发的微动损伤导致试样表面应力集中，降低了试件的微动疲劳强度。试样表面在空气中形成的氧化膜和在模拟体液中形成的氧化膜之间的差异似乎影响了微动损伤的形态。3)研究了Zr基非晶态合金在汉克斯溶液和细胞培养基等不同模拟体液中的极化行为，以检验其在模拟体液中的耐腐蚀性。结果表明，该非晶合金在含氨基酸或蛋白质的流体中具有较高的抗一般腐蚀和点蚀性能。此外，与传统的晶体合金相比，Zr基非晶合金的杨氏模量较低，约为75 MPa，因此，如果提高室温下的塑性变形能力，它们适用于医疗应用。少

Fretting fatigue tests were carried out in a simulated body fluid using a Zr-based bulk amorphous alloy and its fretting fatigue behavior was studied. The fretting fatigue limits were compared with those of conventional metallic materials in air and in the simulated body fluid and the fretting fatigue crack nucleation mechanism was discussed using SEM observation of the fracture surfaces and XPS analysis of the fretted areas on the specimen surface. Corrosion behavior of Zr-based bulk amorphous alloys was also studied in various simulated body fluids.The results obtained are as follows.1) The tensile strength of a Zr-based bulk amorphous alloy was similar to that of pure Ti. However, the amorphous alloy exhibited the unique behavior that the fretting fatigue strength is higher in the simulated body fluid than that in air, while the fretting fatigue strength of Ti-6Al-4V was lower in the simulated body fluid than in air.2) The effect of environment on the fretting fatigue strength for t … More he Zr-based bulk amorphous alloy could be explained as follows. SEM observation showed that the morphology of the fretted area on the specimen surface was different between the specimens tested in air and in the simulated body fluid, and the fretting damage in the simulated body fluid was induced uniformly within the contact area of the fretting pad, while the damage in air was induced locally. Thus, the fretting damage induced locally in air introduced the stress concentration on the specimen surface and decreased the fretting fatigue strength. The difference between oxide films formed on the specimen surface in air and in the simulated body fluid seemed to affect the morphology of the fretting damage.3) We also studied the polarization behavior of a Zr based amorphous alloy in various simulated body fluids such as Hanks' solution and cell culture medium in order to examine the corrosion resistance in simulated body fluids. We found that the amorphous alloy has higher resistance to general corrosion and pitting corrosion in the fluids containing amino acid or protein.In addition, Zr based amorphous alloys have the lower Young's modulus of about 75 MPa, compared with that of conventional crystalline alloys and therefore, they are suitable for medical applications, if their plastic deformability at room temperature is improved. Less