新型生物医用超细晶Ti-Cu合金

NOVEL ULTRAFINE GRAINED TI-CU ALLOYS FOR BIOMEDICAL APPLICATIONS

董瑞

11649158

硕士

材料工程

任富增

2018-05-27

2018-06-25

哈尔滨工业大学

深圳

生物医用纯钛及其合金因为具有高比强度、优异的耐腐蚀性能和良好的生物相容性等优点，被广泛应用于骨科和牙科植入物中。然而，仍有一些缺点需要克服，特别是低耐磨性和缺乏抗菌活性。为了解决这些问题，本文采用机械合金化和放电等离子烧结相结合的方法，制备了 Cu 含量分别为 5 at%和 25 at%的超细晶 Ti-Cu 合金。借助 XRD、SEM、TEM 等分析手段，系统地研究了其相组成、微观结构、力学性能、耐磨性能、耐腐蚀性能、生物相容性和抗菌性能。研究表明，经过高能球磨后，Ti、Cu 粉末强制互溶，形成富含 α-Ti 的 Ti-Cu过饱和固溶体。经过烧结，Ti-Cu 固溶体分解为 α-Ti 和 Ti2Cu 两相，在 Ti95Cu5中，金属间化合物 Ti2Cu 相弥散分布在 α-Ti 相的基体周围。而在 Ti75Cu25 合 金中，α-Ti 相均匀分布在 Ti2Cu 相基体中。两种 Ti-Cu 合金均具有超细晶粒组 织，Ti95Cu5 合金晶粒中，α-Ti 晶粒尺寸为 3 μm，Ti2Cu 晶粒尺寸为 0.43 μm； 而 Ti75Cu25 合金中两相的晶粒均小于 1 μm。超细晶组织和第二相强化使得Ti-Cu 合金具有较高的硬度和压缩强度，硬度分别达到 404.2±14.2 HV 和425.7±8.3 HV，断裂强度分别达到 1933.9 MPa 和 2135.4 MPa，并且保持良好的断裂韧性（>20%）。摩擦磨损实验表明，Cu 元素的添加，引入 Ti2Cu 相，提高了纯钛的耐磨性能。并且，在人工唾液中的电化学腐蚀测试表明，Ti-Cu 合金保留了纯钛优异的耐腐蚀性能，并有所提高。通过体外细胞培养和 Cu 离子释放测试表明，Cu 离子的释放量对人体无害，并且 Ti-Cu 合金表面细胞生长、增殖状态良好，具有可以与纯钛媲美的生物相容性。经过平板计数法测量抗菌性能表明，加入抗菌元素 Cu 后，Ti-Cu 合金具有一定抗菌能力，Ti75Cu25 合金对大肠杆菌的抗菌能力达到 86.8%。

Titanium and its alloys have been widely used as orthopedic and dental implants due to their high specific strength, excellent corrosion resistance and good biocompatibility. However, there are still several drawbacks to be overcome, particularly low wear resistance and lack of antibacterial activity. To solve these problems, in the present thesis, we have fabricated ultra-fine grained Ti-Cu alloys with Cu concentration of 5 at% and 25 at% by a combination of mechanical alloying and spark plasma sintering. Then, we have systematically investigated their phase compositions, microstructure, mechanical properties, wear performance, corrosion resistance, cytocompability and antibacterial properties.The results show that elemental titanium and copper powders can be forced into the formation of α-Ti rich supersaturated Ti-Cu solid solutions. During SPS, the Ti-Cu solid solutions decomposed into α-Ti and the intermetallic compound Ti2Cu.Such spark plasma sintered Ti95Cu5 alloy consists of Ti2Cu precipitates uniformly distributed into the α-Ti matrix. Conversely, in the Ti75Cu25 alloy, α-Ti grains uniformly distributed in the Ti2Cu matrix. Both Ti-Cu alloys have ultrafine grained microstructure. For the Ti95Cu5 alloy, the grain sizes of α-Ti and Ti2Cu are of 3 μmand 0.43 μm, respectively. For the Ti75Cu25 alloy, the grain size of both α-Ti and Ti2Cu are less than 1 μm. The ultrafine-grained microstructure and second-phase strengthening render the present Ti-Cu alloys much higher hardness and compressive yield strength. The hardness reaches up to 404.2 ±14.2 HV and 425.7 ±8.3 HV, respectively. The fracture strength reaches up to 1933.9 MPa and 2135.4MPa, respectively, while still demonstrating good plasticity with fracture strain exceeding 20%. Dry sliding wear tests show that with the addition of Cu and thusintroducing the intermetallic compound Ti2Cu phase. The wear resistance was improved as compared with pure titanium. Moreover, electrochemical corrosion tests in artificial saliva indicate that the Ti-Cu alloys maintains the excellent corrosion resistance. In vitro cell culture shows that the release of Cu ions isnontoxic to the osteoblastic cells. Such Ti-Cu alloys also demonstrate excellent biocompatibility as that of pure titanium. The antibacterial properties measured by plate counting shows that Ti-Cu alloy has good antibacterial activity with actibacterial rate up to 86.8% for Ti75Cu25 alloy against E. coli.

Ti-Cu 合金 微观结构 力学性能 磨损性能 生物相容性 抗菌性能

Ti-Cu alloys microstructure mechanical properties wear biocompatibility antibacterial

中文

联合培养

南方科技大学

董瑞. 新型生物医用超细晶Ti-Cu合金[D]. 深圳. 哈尔滨工业大学,2018.