Development and application of ultra-high strength titanium alloy thin sheet and fine-diameter wire coated with TiN

各种医疗植入装置或材料，如金属支架或功能性电刺激（FES）电极，都需要高强度的钛薄板或细直径的钛丝。本研究源于新发现在直径为25mm的重冷拔线材上镀TiN可获得超高强度。结果表明：(1)新型β型钛合金Ti-14%Mo-3%Nb-1.5%Zr-0.08%[O]完全满足靶材性能，其生物相容性优于316L钢，与Ti-6A1-4V合金相当，冷加工性比实际钛合金有很大提高。(2)用这种新合金制成了厚度可达33毫米的薄板和直径50毫米的细丝。板材或线材的这些限制尺寸是由于所使用的轧机和制造技术的限制。事实上，用阳极氧化工艺代替大气氧化工艺，在孔模拉深过程中通过加热防止粘接现象，可以显著提高冷加工性，这表明该合金可以制造更细厚度的板材或更细直径的线材。(3)采用PVD法对316L钢丝进行极薄TiN涂层处理，可获得极高的强度，可达3100 MPa以上，未镀TiN冷拔钢丝的白强度为2400 MPa。由于无法制造出直径为25mm的新型钛合金线材，因此无法证实在该合金线材上TiN涂层具有类似的强化效果。提出了一种能够在细直径线材上连续镀膜的工业PVD工艺，并对表面镀膜工艺参数进行了优化。(4)在0.9% NaCl生理盐溶液中，在310K下测试了TiN涂层对19股316L型钢丝绳旋转弯曲疲劳性能的影响，结果表明，TiN涂层抑制了未涂层钢丝在高循环范围内钢丝间的侵蚀，大大提高了钢丝的疲劳强度。这表明用TiN包覆的细径线材可以作为FES电极的材料。同时进行了细径TiN包覆丝与超塑性Zn-Al合金薄片包覆复合材料的制备试验，但仍处于初步试验阶段。少

A high strength titanium thin sheet or fine diameter wire are needed for various medical implant devices or materials such as a metallic stent or a functional electrical stimulation (FES) electrode. This study originated from new discovery that ultra-high strength could he obtained by TiN coating on heavily cold drawn wire with a 25mm diameter. The results were summarized as followed(1) New β type titanium alloy, Ti-14%Mo-3%Nb-1.5%Zr-0.08%[O], fully satisfying target properties was developed, and biocompatibility of this alloy was found to be superior over the Type 316L steel and comparable to Ti-6A1-4V alloy, and in cold workability wan much improved over the practical titanium alloys.(2) A thin sheet with a thickness down to 33mm and a fine diameter wire with 50mm were manufactured in this new alloy. These limiting dimensions of a sheet or wire were due to restriction of rolling mill used and manufacturing technology. In fact, surface oxidation by anodizing process in place of atmosp … More heric heating for prevention from sticking phenomena during hole dies drawing was confirmed to improve markedly cold workability, indicating possibility of manufacturing a finer thickness sheet or a finer diameter wire of this alloy.(3) It was found that an extremely higher strength up over 3100 MPa in the Type 316L steel wire was obtained by very thin TiN coating by PVD, white strength of as-cold drawn wire without TiN coating was 2400 MPa. Because of non-achievement of manufacturing a 25mm diameter wire of new Ti alloy, it was unable to confirm similar strengthening in TiN coating on this alloy wire. An industrial PVD process enabling to practice continuous coating on a fine diameter wire and the optimized conditions for processing parameters of surface coating were proposed.(4) The effect of TiN coating on the Type 316L steel wire rope woven with 19 strands on rotating-bend fatigue property was examined in 0.9% NaCl physiological salt solution at 310K and fatigue strength in the high cycle range was much improved due to suppression of erosion which took place among wires during test for non coated wires. This indicates a fine diameter wire coated by TiN can be utilized as a material for FES electrode. Manufacturing test of a composite material by cladding a fine diameter wire coated with TiN and thin sheet of super-plastic Zn-Al alloy was also performed, but it remained in a preliminary test stage. Less