本文選題：層狀復(fù)合材料 + 鈦多晶��； 參考：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：層狀Ti-Al復(fù)合板由交替排列的強(qiáng)度較高的鈦層和塑性好的鋁層通過熱壓-軋制而成,這種材料能夠結(jié)合兩種材料的性能優(yōu)勢(shì),彌補(bǔ)單一的金屬材料的某些方面的不足,表現(xiàn)出更優(yōu)良的特性。本課題主要對(duì)Ti-Al層狀金屬復(fù)合材料中鈦層的力學(xué)行為和復(fù)合材料的增強(qiáng)增韌機(jī)理進(jìn)行研究。采用塑性細(xì)觀力學(xué)方法編寫程序?qū)︹亸椝苄宰冃芜^程進(jìn)行數(shù)值分析。之后選取合理的韌性破壞準(zhǔn)則分析其韌性破壞失效過程和增韌機(jī)理。在此基礎(chǔ)上引入鋁層彈塑性變形的宏觀本構(gòu)關(guān)系以及缺陷層理論,分析隨著各相層厚比變化,Ti-Al層狀金屬復(fù)合材料的增強(qiáng)增韌機(jī)制。本文首先介紹了晶體學(xué)基本理論、多晶體塑性變形的基本理論以及金屬材料變形的韌性破壞準(zhǔn)則。根據(jù)鈦晶格常數(shù)等特點(diǎn)和鈦合金塑性變形研究的相關(guān)實(shí)驗(yàn)得到影響金屬鈦塑性變形過程的主要變形機(jī)制是滑移和孿生,一般數(shù)值分析過程重點(diǎn)考慮滑移機(jī)制。將林同驊模型進(jìn)行改進(jìn)分析推導(dǎo)得到適用于描述多晶體鈦的彈塑性變形過程的塑性細(xì)觀力學(xué)模型。在此基礎(chǔ)上編寫程序?qū)Χ嗑р伒膹椝苄宰冃芜M(jìn)行數(shù)值分析得到能夠體現(xiàn)多晶體鈦細(xì)觀變形特點(diǎn)的應(yīng)力應(yīng)變關(guān)系。這一塑性細(xì)觀力學(xué)模型可以更好的應(yīng)用于數(shù)值分析密排六方晶體的彈塑性變形過程。之后研究了描述金屬材料韌性破壞的斷裂準(zhǔn)則,通過對(duì)實(shí)驗(yàn)結(jié)果的觀察分析得到鈦斷裂形式為微孔聚集型斷裂。選取Rice-Tracey韌性斷裂模型使用閥值控制的方法來描述材料韌性破壞行為,合理的描述了多晶鈦的失效行為。進(jìn)一步改變加載過程,對(duì)不同應(yīng)力狀態(tài)下鈦單軸拉伸進(jìn)行數(shù)值分析,使用韌性斷裂準(zhǔn)則分析不同應(yīng)力狀態(tài)后鈦單軸拉伸的結(jié)果,得到不同應(yīng)力作用下斷裂韌性值C隨應(yīng)變變化關(guān)系。發(fā)現(xiàn)對(duì)應(yīng)于同一應(yīng)變量,有外部應(yīng)力作用與無外部應(yīng)力相比韌性斷裂值C明顯減小了,約束狀態(tài)越強(qiáng),韌性斷裂值C減小越明顯,同時(shí)韌性斷裂值C隨著拉伸方向應(yīng)變不斷增大的趨勢(shì)也減小了。這一分析結(jié)果表明在鈦薄板拉伸過程中垂直于板面方向一定形式的應(yīng)力作用對(duì)于其整體的拉伸有較好的增韌效果。最后引入鋁層彈塑性變形的宏觀本構(gòu)關(guān)系和缺陷層模型,得到均勻介質(zhì)層和考慮缺陷層模型下的不同層厚比的層狀金屬復(fù)合板拉伸的應(yīng)力應(yīng)變關(guān)系。使用韌性斷裂準(zhǔn)則分析考慮缺陷層時(shí)不同厚度比的層狀金屬復(fù)合板的斷裂韌性。發(fā)現(xiàn)一定范圍內(nèi),鈦層的含量越高,缺陷層對(duì)于鈦拉伸破壞的影響減小了,從而解釋了隨著鈦層和鋁層厚度比的增大,復(fù)合材料的增強(qiáng)增韌機(jī)制。
[Abstract]:The laminated Ti-Al composite plate is composed of titanium layer with high strength arranged alternately and aluminum layer with good plasticity by hot-pressing rolling. This material can combine the performance advantages of the two kinds of materials and make up for the deficiency of some aspects of a single metal material. Show better characteristics. In this paper, the mechanical behavior of titanium layer and the reinforcing and toughening mechanism of Ti-Al laminated metal composites are studied. The plastic meso-mechanical method is used to program the elastic plastic deformation of titanium. Then the failure process and toughening mechanism of ductile failure are analyzed by selecting reasonable ductile failure criterion. On the basis of this, the macroscopic constitutive relation of elastoplastic deformation of aluminum layer and the theory of defect layer are introduced, and the reinforcing and toughening mechanism of Ti-Al laminated metal composite is analyzed with the change of the thickness ratio of each phase layer. In this paper, the basic theory of crystallography, the basic theory of polycrystalline plastic deformation and the ductile failure criterion of metal materials are introduced. According to the characteristics of titanium lattice constants and the relevant experiments on the plastic deformation of titanium alloys, the main deformation mechanisms affecting the plastic deformation of titanium alloys are slip and twinning. The general numerical analysis focuses on the slip mechanism. Based on the improved analysis of Lin Tonghua model, a plastic meso-mechanical model suitable for describing the elastoplastic deformation process of polycrystalline titanium is derived. On this basis, a program is written to analyze the elastoplastic deformation of polycrystalline titanium by numerical analysis, and the stress-strain relationship which can reflect the characteristics of meso-deformation of polycrystalline titanium is obtained. This plastic mesomechanical model can be applied to the numerical analysis of elastic-plastic deformation process of dense hexagonal crystals. Then the fracture criterion describing the ductile failure of metallic materials is studied. By observing and analyzing the experimental results, it is found that the fracture form of titanium is microporous aggregate fracture. The Rice-Tracey ductile fracture model is selected to describe the toughness failure behavior of the material by using the threshold control method, and the failure behavior of polycrystalline titanium is described reasonably. Further changing the loading process, the uniaxial tension of titanium under different stress states is numerically analyzed, and the results of uniaxial tension of titanium under different stress states are analyzed by using the ductile fracture criterion. The relationship of fracture toughness C with strain under different stress is obtained. It is found that the ductile fracture value C decreases obviously when the external stress is applied to the same strain, and the stronger the constrained state is, the more obvious the ductile fracture value C decreases. At the same time, the ductile fracture value C decreases with the strain increasing in the tensile direction. The results show that a certain form of stress acting perpendicular to the plate during the tensile process of the titanium sheet has a good toughening effect on the overall tensile strength of the titanium sheet. Finally, the macroscopic constitutive relation and defect layer model of elastic-plastic deformation of aluminum layer are introduced to obtain the stress-strain relationship between uniform medium layer and laminated metal composite plate with different thickness ratios under the model of defect layer. The ductile fracture criterion is used to analyze the fracture toughness of laminated metal clad plates with different thickness ratio when the defect layer is considered. It is found that the higher the content of titanium layer, the less the effect of defect layer on tensile fracture of titanium, which explains the reinforcing and toughening mechanism of composites with the increase of thickness ratio of titanium layer to aluminum layer.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB331

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本文編號(hào)：1781576