| 摘要: | 在近二十年來，金屬材料被快速地發展於醫療器具上的使用，是因為發現鈦金屬對人體擁有良好的生物相容性，而目前最普遍的使用是在於手術外科的骨骼植入材，例如CP Ti、Ti64和Ti6Al7Nb。近年來研發出新型材料-鈦基金屬玻璃，它有相當優越於一般結晶材料的生物相容特性，因為它沒有結晶構造上的缺陷，例如差排、晶界和雙晶，所以材料所呈現的是均勻的化學組成、高強度、低楊氏係數和良好的抗腐蝕能力，雖然從生物醫療的觀點來看，鈦基金屬玻璃是優秀於一般的結晶材料，但以上兩種材料在長時間使用的狀態下仍存在著一些疑慮，而主要問題點在於(1)不匹配的楊氏係數(皮質骨10~30 GPa，Ti64 110~120 GPa，鈦基金屬玻璃 80~90 GPa)，當植入材受到彈性的彎曲變形時，容易造成骨頭無法均勻將負載分散在植入材料上造成所謂的遮蔽效應，這會引起人體組織的受損，以及增加恢復的時間，(2)經化學腐蝕或是磨耗釋出有毒金屬離子或顆粒的可能性，在鈦基金屬材料中往往為了增加機械性質或是玻璃形成能力，而添加對人體不友善的元素，例如Ti64中的Al和V，鈦基金屬玻璃的Ni和Cu。本實驗室已成功開發出具低熔點高玻璃形成能力之無毒鈦基金屬玻璃合金Ti42Zr35Ta3Si5Co12.5Sn2.5，結合該合金之高玻璃形成能力、寬廣過冷液相區間、高強度、良好的抗腐蝕能力，並利用其過冷液相區的超塑性質，可將該金屬玻璃合金以熱壓成形方式製作出符合人骨的楊氏係數及高強度之漸層孔隙多孔材料，成為可提供骨細胞生長空間的金屬基仿生植入材。本計畫提出「無毒開放性孔洞漸層鈦基金屬玻璃植入材之開發」，而計畫為期參年:第一年將原已開發之具高玻璃形成能力鈦鋯基金屬玻璃合金Ti42Zr35Ta3Si5Co12.5Sn2.5為基材，進行熱塑成形的製程條件及熱塑變形前後之微結構分析，做有系統之探討來勾劃出鈦基金屬玻璃在過冷液相温度區間的熱成形條件範圍。第二年將依據前一年所獲得之過冷液相温度區間的熱成形條件範圍，系統化探討使用不同金屬造孔劑來製作不同單一孔隙度金屬玻璃多孔材料之最佳加工製程條件，。第三年將依據前一年獲得之最佳造孔劑和單一孔隙度金屬玻璃多孔材料之最佳加工製程條件進行漸層孔隙結構設計及其製程條件之探討，找尋出可以完全匹配人體骨頭行為的仿生植入材，期望能將多孔鈦基金屬玻璃材料推廣至商業生醫植入材。 ;In this decade, metallic materials have been rapidly developed for the biomedical purpose after the discovery of good biocompatibility on the Ti metal. The most popular applications of the Ti alloys (e.g. pure (cp) Ti, Ti-6Al-4V and Ti-6Al-7Nb) as biomedical implant materials is in the field of trauma and orthopedic surgery. Recently, several novel Ti-based metallic glasses (Ti-MGs) with superior biomedical properties compared to its crystalline material counterpart has also been developed. These Ti-MGs have no crystal structural defects (such as dislocations, grain boundaries or twins), homogenous chemical composition, higher strength, lower Young’s modulus, and much better corrosion resistance. Although the Ti-MGs present better biomedical properties than the crystalline Ti alloys. However, based on the long-term durability and health concerns, two serious problems still exist in the above-mentioned two kinds of Ti-based materials. The problems are (1) The mismatch of the Young’s modulus (E) between the bone (E=10~30 GPa for cortical bone) and the implant (E=110~120 GPa for Ti-6Al-4V alloys, 80~90 GPa for Ti-MG). Large modulus mismatch will cause stress-shielding on the bone nearby the implant and induced tissue loss and increasing recovery time. (2) The release of toxic metallic ions and/or particles through corrosion and wear processes. Some harmful elements are frequently added in the Ti alloy systems in order to improve mechanical properties and glass-form ability (GFA) (Al, V for Ti-6Al-4V alloys, Ni, Cu for Ti-MG). Accordingly, in this study, we are going to select the non-toxic Ti-based metallic glass (Ti42Zr35Ta3Si5Co12.5Sn2.5) which was invented and got patent from our previous study) as the based alloy to prepare the metallic glass powder. Then, these metallic glass powder can be fabricated into a gradient porosity metallic glass foam via thermoplastic forming process with spacer method for application on the biomedical implant. In the 1st year, In the 2nd year, the major work will focus on the process study of MG powder manufacturing and thermoplastic forming. The microstructure changes of hot-pressed Ti-based bulk metallic glass foam (BMG) will be investigated and working window of thermoplastic forming process will be established. For the 2nd year, based on the experimental results of 1st year study on the thermoplastic forming process. The effect of different spacer materials on the hot-pressing process for fabricating the uni-porosity bulk metallic glass foam (BMGF) with different porosity ratio (30~60 vol.%) will be systematic investigated. The optimum spacer material and working window of hot-pressing process will be figured out. The 3rd year, the experimental results of 2nd year study on the selection of optimum spacer material and working window of hot-compressing process for fabricating the uni-porosity metallic glass foam will be applied on the structure design of gradient porosity and the investigation of working window for producing the gradient porosity bulk metallic glass foam. Hopefully, the Ti-based BMGFs could be applied into the biomedical implant in the future. |
