發(fā)布時(shí)間：2018-01-15 15:09

  本文關(guān)鍵詞：超低彈性模量Ti-Nb基亞穩(wěn)β鈦合金的相變和力學(xué)行為　出處：《江蘇大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 亞穩(wěn)β型鈦合金 固態(tài)相變 微觀結(jié)構(gòu) 彈性常數(shù) 力學(xué)行為

【摘要】：鈦及鈦合金憑借其低彈性模量、良好的綜合力學(xué)性能、生物相容性和耐腐蝕性而廣泛應(yīng)用在生物植入件上。然而,目前應(yīng)用最廣的鈦和鈦合金(如Ti-6Al-4V)的彈性模量約為110GPa,仍高于人骨的彈性模量(約為30GPa),由于植入件與人骨彈性模量的不匹配,在植入時(shí)容易誘發(fā)“應(yīng)力屏蔽”效應(yīng)。此外,Al和V的釋放會(huì)導(dǎo)致長期的健康問題,如骨軟化癥和神經(jīng)性疾病。因此,研發(fā)低模量、高強(qiáng)度且完全由無毒元素組成的新型β型鈦合金已成為生物醫(yī)用植入材料的研究熱點(diǎn)。本文以低模量作為合金成分設(shè)計(jì)的主要依據(jù),設(shè)計(jì)研制出Ti-33Nb-4Sn(wt.%)合金,并通過力學(xué)性能試驗(yàn)機(jī)(Mechanical Testing Machine)、X射線衍射儀(XRD)、透射電子顯微鏡(TEM)、原位同步輻射(in-situ synchrotron X-ray diffraction)和利用彈塑性自洽模型(EshelbyKroner-Kneer elastoplastic self-consistent model)等手段系統(tǒng)地研究了熱機(jī)械處理對新型Ti-Nb-Sn合金相變、微觀結(jié)構(gòu)和力學(xué)行為的影響,旨在開發(fā)出低模量和高強(qiáng)度兼?zhèn)涞膩喎�(wěn)β型鈦合金,并揭示其低模量機(jī)制和變形行為的物理機(jī)制,為新型低模量高強(qiáng)度鈦合金的設(shè)計(jì)提供理論指導(dǎo)。研究結(jié)果表明:本文設(shè)計(jì)研制的Ti-33Nb-4Sn(wt.%)合金,固溶態(tài)合金由β和α?馬氏體兩相組成,冷軋?zhí)幚砗蠛辖鸬南嘟M成仍為β和α?馬氏體,冷軋變形后的合金經(jīng)425℃時(shí)效處理30min后,合金主要由β相組成,同時(shí)含有少量的細(xì)小α相,合金抗拉強(qiáng)度為855MPa,彈性模量為36GPa。TEM結(jié)果表明,冷軋和短時(shí)時(shí)效處理過程中引入的高密度位錯(cuò)、細(xì)化晶粒和納米尺度的α相共同作用,賦予合金高的強(qiáng)度,此外由于時(shí)效處理時(shí)間較短,仍保持具有本征低模量的β相,同時(shí)α相的形成量很少,不足以顯著提高合金模量,因此合金模量較低。由此獲得合適的熱機(jī)械處理制度,即冷軋短時(shí)時(shí)效處理能夠使合金兼具高強(qiáng)度和低模量。為探究其低彈性模量機(jī)制的本質(zhì),我們利用彈塑性自洽(EPSC)模型結(jié)合同步輻射技術(shù)計(jì)算出合金的單晶彈性常數(shù),發(fā)現(xiàn)低模量Ti-33Nb-4Sn合金具有與同等價(jià)電子濃度(e/a)的二元合金相當(dāng)?shù)腃?(12.6GPa)以及明顯偏低的C44(22.4GPa),基于此我們推斷,通過熱機(jī)械處理得到的亞穩(wěn)β型鈦合金,其具有較低的剪切模量C?和異常偏低的剪切模量C44,兩者共同作用可獲得低彈性模量。同時(shí)為了研究其變形行為的物理機(jī)制,我們嘗試?yán)猛捷椛浼夹g(shù)將材料的變形行為與細(xì)微的結(jié)構(gòu)轉(zhuǎn)變建立起聯(lián)系,發(fā)現(xiàn)固溶態(tài)合金在拉伸過程中出現(xiàn)“雙屈服”現(xiàn)象的原因是由于馬氏體變體的再取向和應(yīng)力誘發(fā)馬氏體相變,Ti-33Nb-4Sn合金經(jīng)冷軋?zhí)幚砗?合金中存在的大量位錯(cuò)和晶界能夠?qū)︸R氏體切變產(chǎn)生明顯阻礙作用,因此冷軋態(tài)合金在拉伸過程中應(yīng)力誘發(fā)馬氏體相變的程度明顯小于固溶態(tài)合金,其在拉伸過程中呈現(xiàn)出“非線性”變形。而冷軋短時(shí)時(shí)效態(tài)合金在變形行為中比固溶態(tài)和冷軋態(tài)的合金都要穩(wěn)定,是因?yàn)榻?jīng)冷軋短時(shí)時(shí)效處理后合金中高密度位錯(cuò)、晶界和納米尺度的α相對抑制拉伸行為中應(yīng)力誘發(fā)馬氏體相變起到了重要作用,因此其宏觀拉伸應(yīng)力應(yīng)變曲線在彈性階段呈現(xiàn)出與常規(guī)材料一致的“線彈性”變形。
[Abstract]:Titanium and titanium alloy with low elastic modulus, good mechanical properties, biocompatibility and corrosion resistance and is widely used in the biological implant. However, currently the most widely used titanium and titanium alloys (such as Ti-6Al-4V) the elastic modulus is about 110GPa, is still higher than the human bone elastic modulus (ca. 30GPa), due to the mismatch of implant and bone elastic modulus, easy at implantation induced by stress shielding effect. In addition, Al and V release will lead to long-term health problems, such as osteomalacia and neurological diseases. Therefore, developing new low modulus, high strength titanium alloy which is entirely non-toxic elements has become a research hotspot of medical implant material. In this paper, a low modulus as the main basis of composition design, design and development of a Ti-33Nb-4Sn (wt.%) alloy, and the mechanical performance testing machine (Mechanical Testing Machine), X ray diffraction Radiometer (XRD), transmission electron microscopy (TEM), in situ synchrotron radiation (in-situ synchrotron X-ray diffraction) and using the elastoplastic self consistent model (EshelbyKroner-Kneer elastoplastic self-consistent model etc.) were studied by means of thermo mechanical treatment on phase transformation of new Ti-Nb-Sn alloy, microstructure and mechanical behavior, in order to develop metastable beta titanium alloy with low modulus and high strength both the physical mechanism and reveal the mechanism of low modulus and deformation behavior, provide theoretical guidance for the design of new low modulus and high strength titanium alloy. The research results show that the design and development of Ti-33Nb-4Sn (wt.%) alloy, solid solution alloy by beta and alpha martensite phase? Composition, phase composition of cold treated alloy is beta and alpha? Martensite after cold rolling alloy is 425 DEG C after aging treatment of 30min alloy is mainly composed of beta, phase composition, and contains a small amount of The small phase, the tensile strength of the alloy is 855MPa, the elastic modulus is 36GPa.TEM. The results show that the high density of dislocation introduced by cold rolling and short-time aging process, refine grain and nano scale alpha phase interaction, with high strength alloy, due to aging treatment for a short time, still has the character of low modulus the beta phase, while alpha phase formation very small, not enough to significantly improve the modulus of alloy, so the alloy of low modulus. The thermal mechanical treatment system, which can make the alloy cold rolling short-term aging treatment with high strength and low modulus. For its inquiry into the nature of low elastic modulus mechanism, we use elastic plastic self consistent (EPSC) model combined with the calculated elastic constants of alloy single crystal synchrotron radiation technology, found that low modulus Ti-33Nb-4Sn alloy with the same equivalent electron concentration (e/a) of the two element alloy equivalent C (12.6GPa) and obvious? Low C44 (22.4GPa), based on this we conclude by thermo mechanical treatment of metastable beta titanium alloy is obtained, which has low shear modulus C and shear modulus C44? Abnormally low, both can obtain low elastic modulus. At the same time in order to study the deformation behavior of the physical mechanism, we tried to use synchronization radiation technology will change the deformation behavior of materials with fine structure to establish contact, find solid solution alloy in tensile process in a "double yield" phenomenon is due to martensite reorientation and stress induced martensitic phase transformation of Ti-33Nb-4Sn alloy after cold rolling process, a large number of dislocations and grain boundaries exist in the alloy can produce obvious effects on the martensitic shear, therefore cold-rolled alloy stress induced martensitic transformation significantly less than solid solution alloy during the stretching process, the tensile process in "Nonlinear" deformation. And cold rolled alloy in short always effect the deformation behaviors than alloy solid solution and cold rolling are stable, because the high dislocation density in the alloy after cold rolling and short-time aging treatment, grain boundary and nano scale alpha relative inhibition tensile behaviour in the important role of stress induced by Ma's transformation, so the macro tensile stress-strain curve in the elastic stage shows with conventional materials with the "elastic" deformation.

【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG146.23

【參考文獻(xiàn)】

相關(guān)期刊論文 前9條

1 郭順;鄭琦;張俊松;程曉農(nóng);;低彈性模量亞穩(wěn)β型Ti-38Nb合金的微觀組織與力學(xué)行為[J];稀有金屬;2015年09期

2 楊銳;郝玉琳;;高強(qiáng)度低模量醫(yī)用鈦合金Ti2448的研制與應(yīng)用[J];新材料產(chǎn)業(yè);2009年06期

3 王明;宋西平;;醫(yī)用鈦合金腐蝕、力學(xué)相容性和生物相容性研究現(xiàn)狀[J];鈦工業(yè)進(jìn)展;2008年02期

4 辛社偉;趙永慶;曾衛(wèi)東;;鈦合金固態(tài)相變的歸納與討論(I)——同素異構(gòu)轉(zhuǎn)變[J];鈦工業(yè)進(jìn)展;2007年05期

5 于振濤;;新型生物醫(yī)用鈦合金研制成功[J];稀有金屬快報(bào);2006年01期

6 徐秀茹;鈦及鈦合金的熱處理[J];稀有金屬快報(bào);2003年06期

7 寧聰琴,周玉;醫(yī)用鈦合金的發(fā)展及研究現(xiàn)狀[J];材料科學(xué)與工藝;2002年01期

8 鄧安華;鈦合金的馬氏體相變[J];上海有色金屬;1999年04期

9 張廷杰;鈦合金相變的電子顯微鏡研究(Ⅲ)——鈦合金中的馬氏體相變[J];稀有金屬材料與工程;1989年04期

，

本文編號(hào)：1428871