醫用合金及其抗菌性於牙體系統之整合性研究

Integral Research of Biomedical Alloys and Anti-bacterial Properties on Dental Engineering System

彭珮雯(Pei-Wen Peng)

指導教授 ： 潘永寧 ； 歐耿良

共同指導教授 ： 王兆祥

國立臺灣大學/工學院/機械工程學研究所/博士(2010年)

https://doi.org/10.6342/NTU.2010.10568

摘要

本研究擬針對牙體工程之合金材料與表面處理工程進行全面性之探討。從材料成形性和切削特性的觀點，研究範圍包括雙相鈦合金（α+β）Ti-4.8Al - 2.5Mo -1.4V 之顯微組織和力學性能、不同銀含量不銹鋼合金之抗菌特性以及Fe - 9Al -30Mn - 1C - 3Cr 合金之可加工性。此外，亦針對鈦金屬表面於放電加工改質後，進行微觀結構、材料特性及生物力學進行研究。
於雙相鈦合金(α+β) Ti-4.8Al - 2.5Mo - 1.4V (Ti14)之研究顯示，於600 ° C 和1000 ° C 之熱處理條件下，合金發生一系列相變化：(α+β)→(α+β+α')→(α'+α'+殘餘β)。（α'+α'+殘餘β）結構具有最大降伏強度（σy = 920 MPa），硬度（HRC 36），和阻尼係數（188.3 × 10-4）。(α+β)結構具有最大伸長率(∼15％)。由研究顯示板條狀α'麻田散體，不僅可增加拉伸強度，提高Ti14 合金硬度，亦於增加Ti14 阻尼能力扮演關鍵作用。
於抗菌合金之研究，研究於304 不鏽鋼合金添加不同銀元素含量。結果顯示於抗菌不銹鋼合金表面產生由鐵和銀所組成之富銀複合物，屬面心立方結構，晶格參數 a = 0.251 nm，研究中並無析出物於合金基體或晶界中析出。當合金中銀含量達0.3 wt%，對於大腸桿菌和金黃色葡萄球菌，具有優良抗菌性，其抗菌率幾近100％。
於 9Al - 30Mn - 1C - 3Cr 合金之機械加工研究，結果顯示表面粗糙度(R)、切割速度(V)，進料(F)和切削深度(d)間，存在一函數關係：R = 0.9281 V-0.5337 f0.4914 d0.0667。合金機械加工後，表面硬度為HV 600。由穿透式電子顯微鏡(TEM)觀察，κ相碳化層((Fe,Mn)3AlCx)以L′12 結構存在，其晶格參數 a = 0.375 nm。合金之熱傳係（0.083 cal/cm2 s °C）低於 AISI 304 不銹鋼（0.098 cal/cm2 s °C）。於加工過程中切削溫度約為 620 ℃。
於鈦金屬放電加工研究中顯示，鈦金屬因放電加工處理，其相結構(nano-(γ-TiH and δ-TiH0.71))有別於未經處理之鈦金屬(Nano-(γ-TiH))。鈦金屬表面因nano-(γ-TiH and δ-TiH0.71)相溶解而產生奈米氧化層，顯示nano-(γ-TiH and δ-TiH0.71)於形成奈米孔洞氧化層具有關鍵性之影響。於有限元素生物力學分析，骨組織和植體間之應力分佈差異，因表面經放電加工處理後降低，顯示應力分佈更均勻，從生物力學的觀點來看，經放電加工表面改質後之植體，可使骨組織獲得早期癒合。

關鍵字

阻尼係數 ； 微結構 ； 富銀複合物 ； 鐵鋁錳碳鉻合金 ； 放電處理

並列摘要

In the current study of dental engineering system, the holistic researches regarding the potential biomaterials, surface modification and antibacterial properties had been conducted. From the perspectives of the material forming and machinability, we were attempt to study microstructure and mechanical behavior of the duplex (α + β) Ti-4.8Al-2.5Mo-1.4V alloy, the bacterial response to stainless steels with various amount of antibacterial agents and the machinability of the Fe-9Al-30Mn-1C-3Cr alloy. In addition, the microstructure and material properties and iomechanical behaviors of the titanium with electrical-discharging process were investigated.
First of all, in the study of the duplex Ti-4.8Al-2.5Mo-1.4V (Ti14) alloy, the phase transformation sequence was found to be (α + β) → (α + β + α′) → (α′ + α″ + residual β) during heat-treatment between 600°C and 1000°C. The (α′ + α″ + residual β) structure exhibited the maximum yield strength (σy = 920 MPa), hardness (HRC 36), and damping coefficient (188.3 × 10-4). However, the (α + β) structure achieved the greatest elongation (~15%). It is believed that the lath-like α′ martensite not only increases the tensile strength, but also enhances the hardness of the Ti14 alloy. Moreover, it also plays a crucial role in increasing the damping capacity of the Ti14 alloy.
The Ag-rich compound was consisted of Fe and Ag elements, and belongs to a FCC structure with the lattice parameter a = 0.251 nm in our antibacterial analysis. No precipitates were found within the matrix and grain boundaries in the present alloys after SHT. When the alloy contains about 0.3 wt.% Ag, it has excellent antibacterial property against both E. coli and S. aureus. It has an AR nearly of 100%.
The effects of phase transformation in the Fe-9Al-30Mn-1C-3Cr alloy on machinability were studied. The relationship among surface roughness (R), cutting velocity (V), feed (f), and cutting depth (d) was found to be R = 0.9281 V-0.5337 f0.4914 d0.0667. Moreover, after machining, hardening of the surface layer to around HV 600 was observed. Transmission electron microscopy (TEM) revealed some κ phase carbides ((Fe,Mn)3AlCx) having an order L′12 structure with lattice parameter a = 0.375 nm in the hardened layer. Furthermore, the heat transfer coefficient of the present alloy (0.083 cal/cm2 s °C) was found to be lower than that of AISI 304 stainless steel (0.098 cal/cm2 s °C). The cutting temperature during machining was approximately 620°C. It is noted that these results have not been previously reported in Fe-Al-Mn-C and Fe-Al-Mn-C-Cr alloys.
Nano-(γ-TiH) and nano-(γ-TiH and δ-TiH0.71) phases were formed by the natural penetration of hydrogen, and lectrical-discharging, respectively. A nanostructural surface and an oxidation layer were formed by the dissolution reactions of nano-(γ-TiH and δ-TiH0.71) phases. Nano-(γ-TiH and δ-TiH0.71) phases are important in the formation of a nanoporous and nanostructural TiO2 layer. The presence of nano-(γ-TiH and δ-TiH0.71) phases on titanium is critical in the preparation of a thick and nanoporous TiO2 layer by electrical-discharging.
In our biomechanical analysis, the difference of stress distribution between fixture and bone tissue was reduced following electrical-discharging. Therefore, the more uniform stress distribution was presented around the Ti-implant interface with the surface modification. From the biomechanical perspective, early healing and osseointegration would be obtained with electrical-discharging.

並列關鍵字

Damping coefficient ； Microstructure ； Fe-Al-Mn-C-Cr alloy ； electrical-discharging ； Ag-rich compound

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