Development of titanium wire ropes for implantable stimulation electrode and their evaluation

1. (1)将α+β型Ti-4.5Al-6Nb-2Fe-2M钛合金拉制成直径为100 μm的金属丝。阳极氧化对拉丝过程中表面氧化物的生成是有效的。在常压氧化成氧化物过程中，建议采用低温工艺。(2)将β型Ti-14Mo-3Nb-1.5Zr钛合金拉制成直径为42 μm的钢丝。采用低温常压氧化法对其表面进行氧化处理。此外，采用阳极氧化法将β型合金拉伸至直径100 μm，拉伸后表面光滑。(3)将CP钛（4N）拉制成直径为47 μm的金属丝。该丝的表面形貌优于市售的直径为46 μm的CP钛丝。(4)将α型Ti-10Zr钛合金拉制成直径为51 μm的线材，表面光洁度和力学性能优异。成功研制出Ti-10Zr钛合金7股、7x7股钢丝绳。(1)直径为47 μm的CP钛丝的最大抗拉强度和总伸长率分别为980 MPa和3.5%。测定了β型Ti-14Mo-3Nb-1.5Zr钛合金丝和α型Ti-10Zr钛合金丝的力学性能。(2)研制的直径为47 μm的CP钛丝和市售的直径为46 μm的CP钛丝的疲劳极限分别为200 MPa和300 MPa。疲劳极限的差异可能是由疲劳试验后的表面粗糙度引起的。经10^7次循环后，市售CP钛丝的表面比研制的CP钛丝光滑。

1. Development of titanium wore for implantable stimulation electrodes(1) α+β type Ti-4.5Al-6Nb-2Fe-2M titanium alloy was drawn to the wire with 100 μm in diameter. Anodic oxidation was effective to the oxide formation on the surface for wire drawing. In the atmospheric oxidation for oxide formation process, it was suggested that the low temperature process was preferred.(2) β type Ti-14Mo-3Nb-1.5Zr titanium alloy was drawn to the wire with 42 μm in diameter. The low temperature atmospheric oxidation was used for oxide formation process on the surface. In addition to that, the β type alloy was drawn to 100 μm in diameter using anodic oxidation, which showed the smooth surface after drawing.(3) CP titanium (4N) was drawn to the wire with 47 μm in diameter. The surface morphology of this wire was better than that of commercially available CP titanium wire with 46 μm in diameter.(4) α type Ti-10Zr titanium alloy was drawn to the wire with 51 μm in diameter, which exhibited the excellent surface smoothness and mechanical properties. The wire ropes with 7 and 7x7 strands made of Ti-10Zr titanium alloy were successfully developed.2. Evaluation(1) The maximum tensile strength and total elongation of CP titanium wire with 47 μm in diameter were 980 MPa and 3.5 %. The mechanical properties of the β type Ti-14Mo-3Nb-1.5Zr titanium alloy wire and the α type Ti-10Zr titanium alloy wire were measured.(2) The fatigue limits of the developed CP titanium wire with 47 μm in diameter and commercially available CP titanium wire with 46 μm in diameter were 200 MPa and 300 MPa, respectively. The difference of fatigue limit may be caused by the surface roughness after fatigue testing. The commercially available CP titanium wire exhibited the smoother surface than developed CP titanium wire after 10^7 cycles.