本文選題：Ti基塊體非晶合金 + 拉伸蠕變行為��； 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：塊體非晶合金作為新材料具有優(yōu)異的力學(xué)性能。本論文的實(shí)驗(yàn)研究對象是鑄態(tài)、退火態(tài)以及不同晶化分?jǐn)?shù)的Ti_(40)Zr_(25)Ni_3Cu_(12)Be_(20)非晶合金,探究了鑄態(tài)非晶合金的拉伸蠕變行為及其機(jī)理,并研究了不同退火態(tài)和晶化態(tài)的Ti_(40)Zr_(25)Ni_3Cu_(12)Be_(20)非晶合金的納米壓痕蠕變行為,對Ti_(40)Zr_(25)Ni_3Cu_(12)Be_(20)非晶合金的壓痕蠕變行為機(jī)理進(jìn)行了探討。借助透射電子顯微鏡(TEM)對拉伸蠕變測試后Ti_(40)Zr_(25)Ni_3Cu_(12)Be_(20)非晶合金樣品的變形區(qū)和夾持區(qū)進(jìn)行了觀察。發(fā)現(xiàn)隨外加應(yīng)力增加和外加溫度的升高,非晶合金樣品的夾持區(qū)保持了較好的非晶態(tài)狀態(tài),變形區(qū)晶化程度則不斷增加,變形區(qū)析出納米晶。觀察了退火態(tài)非晶合金樣品,發(fā)現(xiàn)其微觀結(jié)構(gòu)有序度隨退火溫度的增加而增加,局部出現(xiàn)尺寸為5~10nm的納米晶。觀察了晶化態(tài)非晶合金樣品,發(fā)現(xiàn)樣品析出納米晶的尺寸隨晶化程度的增加而增加。結(jié)合拉伸蠕變曲線、X射線衍射(XRD)分析曲線綜合討論了非晶合金的拉伸蠕變行為。拉伸結(jié)果表明Ti_(40)Zr_(25)Ni_3Cu_(12)Be_(20)非晶合金主要方式為脆斷。蠕變過程主要受到局部非均勻剪切應(yīng)力的作用。拉伸過程中外加載荷對非晶合金原子有序度的影響明顯。對拉伸斷口的形貌進(jìn)行了掃描電子顯微鏡(SEM)分析,斷口展現(xiàn)出明顯的非晶脆斷形貌(河流花樣),隨外加應(yīng)力和溫度的增加,斷口河流花樣的數(shù)量和密度也隨之增加。外加條件為670K、200MPa時斷口出現(xiàn)“熔滴”的情況。借助差示掃描量熱法(DSC)對拉伸蠕變樣品斷口區(qū)和夾持區(qū)進(jìn)行相關(guān)分析,確定了不同應(yīng)力和溫度條件下斷口區(qū)和夾持區(qū)的晶化程度。結(jié)果認(rèn)為隨外加應(yīng)力和溫度的增加材料的晶化程度隨之增加,當(dāng)外加條件為670K、200MPa時材料斷口區(qū)晶化程度最為嚴(yán)重。結(jié)合納米壓痕蠕變曲線、XRD曲線、DSC曲線、TEM觀察綜合分析了退火態(tài)非晶合金的納米壓痕蠕變行為。隨退火溫度的增加,Ti_(40)Zr_(25)Ni_3Cu_(12)Be_(20)非晶合金樣品的有序度隨之增加,且抗蠕變性能增加,而鑄態(tài)非晶合金展現(xiàn)出最差的抗蠕變性能,320℃退火一小時抗蠕變性能為研究樣品中最好。XRD結(jié)果顯示樣品保持良好的非晶態(tài),TEM顯示樣品隨退火溫度的增加未發(fā)生晶化現(xiàn)象,原子有序度隨之增加。另外,隨外加載荷的增加,樣品的抗蠕變性能隨之發(fā)生變化,納米壓痕金剛石壓頭壓入樣品表面的深度隨外加載荷的增加而增加,保載300s時間內(nèi)蠕變位移量隨載荷增加而增加,穩(wěn)態(tài)蠕變階段非晶合金的穩(wěn)態(tài)蠕變速率隨外加載荷的增加而增加。系統(tǒng)開展了晶化態(tài)非晶合金的納米壓痕蠕變行為。XRD曲線顯示經(jīng)過不同程度晶化處理后,樣品發(fā)生了不同程度的晶化,DSC曲線得到了其精確的晶化分?jǐn)?shù)。TEM圖和電子衍射圖結(jié)果顯示材料在晶化處理后出現(xiàn)大量的納米晶粒。納米壓痕蠕變曲線結(jié)果顯示,在同載荷條件下,隨晶化程度的增加材料的抗蠕變性能增強(qiáng)。在晶化程度相同時,樣品對外加載荷依賴性強(qiáng),隨外加載荷的增加,壓頭壓入表面的深度增加,蠕變穩(wěn)態(tài)階段的蠕變位移量增加,穩(wěn)態(tài)蠕變速率增加。
[Abstract]:The bulk amorphous alloys have excellent mechanical properties as new materials. The experimental study in this paper is Ti_ (40) Zr_ (25) Ni_3Cu_ (12) Be_ (20) amorphous alloy as cast state, annealed state and crystallization fraction. The tensile creep behavior and its mechanism of as cast amorphous alloys are investigated and the Ti_ (40) Zr_ (25) (40) Zr_ (25) of different annealed and crystalline states are studied. The indentation creep behavior of Ni_3Cu_ (12) Be_ (20) amorphous alloy was investigated in the indentation creep behavior of Ti_ (40) Zr_ (25) Ni_3Cu_ (12) Be_ (20) amorphous alloy. By means of transmission electron microscopy (TEM), the deformation zone and holding area of Ti_ (40) Zr_ (25) Ni_3Cu_ (12) Be_ (20) amorphous alloy samples after tensile creep test were observed. With the increase of external stress and the increase of external temperature, the holding area of amorphous alloy samples keeps a better amorphous state, the crystallization degree of the deformation zone is increasing and the nanocrystalline is precipitated in the deformation zone. The annealed amorphous alloy samples are observed and the microstructure order degree increases with the increase of annealing temperature, and the local appearance size is 5~. 10nm nanocrystals. The crystalline amorphous alloy samples were observed. It was found that the size of the precipitated nanocrystals increased with the increase of the crystallization degree. The tensile creep behavior of amorphous alloys was discussed by the X ray diffraction (XRD) analysis curve combined with the tensile creep curve. The tensile results showed that Ti_ (40) Zr_ (25) Ni_3Cu_ (12) Be_ (20) amorphous alloy was the main square alloy. The creep process is mainly affected by local nonuniform shear stress. The effect of loading on the order degree of amorphous alloy atoms is obvious in the process of stretching. The morphology of the tensile fracture surface is analyzed by scanning electron microscope (SEM). The fracture surface shows obvious amorphous brittle fracture morphology (river pattern), with the external stress and temperature. In addition, the number and density of the fractured river pattern increased with the addition of the addition of "droplets" on the fracture surface at 670K and 200MPa. By means of differential scanning calorimetry (DSC), the correlation analysis between the fracture zone and the holding area of the tensile creep samples was carried out, and the crystallization degree of the fracture zone and the holding area under different stress and temperature conditions was determined. It is considered that the crystallization degree of the material increases with the added stress and temperature. When the external condition is 670K and 200MPa, the crystallization degree of the fracture zone is the most serious. The nano indentation creep behavior of the annealed amorphous alloy is synthetically analyzed with the nano indentation creep curve, the XRD curve, the DSC curve and the TEM observation. With the increase of annealing temperature, Ti_ (4) 0) the order degree of Zr_ (25) Ni_3Cu_ (12) Be_ (20) amorphous alloy increases and the creep resistance increases, while the cast amorphous alloy exhibits the worst creep resistance. The one hour anti creep resistance at 320 C can show the best amorphous state for the best.XRD results in the sample, and the TEM display sample increases with the increase of annealing temperature. As the crystallization occurs, the atomic order degree increases. In addition, the creep resistance of the sample can be changed with the increase of the loading charge. The depth of the nano indentation diamond press into the sample surface increases with the increase of the loading charge. The creep displacement increases with the load increasing in the 300s time, and the amorphous alloy in the steady creep stage. The steady-state creep rate increases with the increase of external loading. The.XRD curve of the nano indentation creep behavior of crystalline amorphous alloys shows that after different degrees of crystallization, the samples have been crystallized at different degrees. The DSC curves obtained the precise crystallization fraction.TEM diagram and the results of the electron diffraction diagram showing that the material is crystallized in the crystallization. The nano indentation creep curves show that the creep resistance of the material increases with the increase of the degree of crystallization under the same loading condition. With the same crystallization degree, the sample has strong dependence on the loading charge, the depth of the pressure head pressure in the surface increases with the increase of the loading charge, and the creep position in the steady state of the creep. The displacement increases and the steady state creep rate increases.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG139.8

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