熱處理對Ti-22Hf合金之生醫特性影響

Effects of Heat Treatment on the Biomaterial Properties of Ti-22Hf Alloy

鍾承恩(Zhong Cheng-En)

指導教授 ： 趙志燁

國立屏東科技大學/工學院/機械工程系所/碩士(2023年)

https://doi.org/10.6346/NPUST202300063

摘要

鈦與鈦合金具有低密度、高比強度、優異抗腐蝕性、以及生物相容性佳的特性，在工業、航太、軍事和醫療領域被廣泛的應用。其間，在醫療領域中，常見合金為G4純鈦與Ti-6Al-4V-ELI，因其楊氏係數高於人骨的楊氏係數，故常會誘發應力遮蔽效應，使原生骨退化或疏鬆。另，添加的合金元素中，Al被視為阿茲海默症的潛在危險因子，而V則可能誘發組織周圍神經病變。因此，發展低楊氏係數與無Al與V之β型鈦合金，為醫療領域主要發展趨勢之一。近年來，大部分學者，主要探討添加Mo，Ta，Nb與Zr合金元素的生醫特性；鮮少探討添加Hf合金元素的影響。因此，本文主要探討Ti-22Hf合金之生醫特性，針對鍛造Ti-22Hf合金，於α相區(800℃與500℃)進行12小時與24小時熱處理後，分析其顯微結構、楊氏係數，以及生物相容性(細胞毒性與電化學分析)。主要結果，如下：
1. 鍛造Ti-22Hf合金具等軸晶結構，平均晶粒為7.64μm。經高溫800 ℃12與24小時熱處理後，晶粒發生成長現象，平均晶粒分別為8.37μm與14.08μm。而經500℃12與24小時熱處理後，晶粒發生細化與成長特徵，平均晶粒分別為6.92μm與8.35μm。另外，XRD數據顯示，G4純Ti具HCP結構，晶格常數為a=0.295nm、c=0.468nm；Ti-22Hf合金亦具HCP結構，其晶格常數值大於G4純Ti，a=0.298nm、c=0.472nm。此外，鍛造後Ti-22Hf合金XRD繞射峰值強度最高為(101 ̅1)平面；而熱處理試片，繞射峰值強度最高為(112 ̅0)平面。
2. 鍛造Ti-Hf合金的楊氏係數為140.14GPa，經800℃/12h、800℃/24h、500℃/12h與500℃/24h熱處理後，其楊氏係數分別為124.82GPa、114.34GPa、106.42GPa、108.81GPa，熱處理試片楊氏係數呈現下降趨勢。
3. 生物相容性研究顯示：G4純鈦3T3小鼠細胞存活率為64.8%，經不同處理之Ti-22Hf合金，則介於62.9~80.4%之間。純鈦的腐蝕電位為-0.481V，經不同處理之Ti-22Hf合金，其腐蝕電位則介於-0292V ~ -0.519V之間。Ti-22Hf熱處理試片的生物相容性優於G4純鈦。

關鍵字

鈦-鉿 ； 顯微結構 ； 生物相容性 ； 楊氏係數 ； 腐蝕電位

並列摘要

Owing to low density, high strength, well corrosion and biocompatibility, Titanium and Titanium alloys have been applied on industry, military and biomaterial field. Meanwhile, on biomaterial field, the Young’s modulus of G4 and 64Ti-ELI is higher than human bone inducing to stress field effect. And, toxic of Al and V elements occurred. Currently, the developments of β-phase Ti alloys with lower Young’s Modulus are important, of which the Ti-Mo, Ti-Ta, Ti-Ta-Nb, and Ti-Zr alloy system been wildly investigated. However, seldom information concerning with Ti-Hf alloy. Therefore, the purposes of present studies are to investigate the Ti-22Hf alloy during hot-press on α-phase region. And the studies of the microstructure analysis, biocompatibility and Young’s modulus are also performed. Some results are described as following:
1. The microstructures of as-forged Ti-22Hf alloy for various heat treatments are essentially equi-axied structures, the average grain size is 7.64μm. After 800℃/12hr and 24hr heat treatment, the grain is growth, the average grain size is 8.37μm and 14.08μm. After 500℃/12hr and 24hr heat treatment, the grain is refinement and growth, the average grain size is 6.92μm and 8.35μm. Based on the XRD data, the lattice parameter of pure Ti is a=0.295nm, c=0.468m, the Ti-22Hf alloy belongings to HCP structure, lattice is bigger than G4 pure Ti, the lattice parameter of Ti-Hf alloy is a=0.298nm、c=0.472nm. The maxima diffraction peak of as-forged Ti-Hf alloy is (101 ̅1) plane. After heated treatment, the maxima diffraction peak is (112 ̅0) plane.

2. The Young’s modulus of the as-forged Ti-22Hf alloy is 140.14GPa, as-forged Ti-22Hf alloy heat treatment with 800℃/12h, 800℃/24h, 500℃/12h, and 500℃/24h are 124.82GPa, 114.34GPa, 106.42GPa, 108.81GPa, respectively. The Young’s modulus of heat treatment Ti-22Hf alloy is lower than as-forged Ti-22Hf.
3. Based 3T3 cell toxic data, the cell viability of the G4 pure Ti is 64.8%, the cell viability of Ti-22Hf alloy with different treatment are in range of 62.9% and 80.4%. The corrosion voltages of G4 pure Ti is -0.481V, and the corrosion voltages of present specimen are in range of -0.519 and -0.292V. The biocompatibility of heat treatment Ti-22Hf alloy is better than G4 pure Ti.

並列關鍵字

Ti-Hf ； microstructure ； biocompatibility ； Young's Modulus ； Corrosion voltage

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