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

各种医疗植入设备或材料，如金属支架或功能性电刺激(FES)电极，都需要高强度的钛薄片或细直径金属丝。这项研究源于一项新发现，即在直径25 mm的大冷拔钢丝上涂覆TiN可以获得超高强度。结果表明：(1)研制出了性能完全满足目标要求的新型β钛合金--Ti-14%Mo-3%Nb-1.5%Zr-0.08%[O]，该合金的生物相容性优于316L钢，与Ti-6Al-4V合金相当，冷加工性能较实际钛合金有较大改善。薄板或线材的这些极限尺寸是由于所使用的轧钢机和制造技术的限制。事实上，用阳极氧化工艺代替atmop…进行表面氧化。为防止模具拉拔时的粘结现象，进一步的热处理可显著改善冷加工性能，表明该合金有可能生产出更薄的薄板或更细的线材。(3)采用PVD超薄TiN涂层可使316L钢丝获得极高的强度，达到3100 Mpa以上，未涂TiN的冷拔钢丝的白色强度为2400 Mpa。由于直径为25 mm的新型钛合金线材的制造不成功，无法确认该合金线材上的TiN涂层具有类似的强化效果。研究了TiN涂层对钢丝绳316L钢丝绳310K在0.9%NaC l生理盐溶液中的旋转弯曲疲劳性能的影响，并对未涂层钢丝绳在高周疲劳强度范围内的磨损进行了抑制。这表明镀TiN的小直径焊丝可以作为FeS电极的材料。此外，还进行了镀TiN的细径钢丝与超塑性锌铝合金薄板复合的复合材料制造试验，但仍处于初步试验阶段。较少

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