發(fā)布時(shí)間：2018-02-03 04:39

  本文關(guān)鍵詞： Ti-Al合金 密度泛函理論 第一性原理 熱力性能 電子結(jié)構(gòu)　出處：《沈陽(yáng)工業(yè)大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：Ti-Al合金是一類(lèi)倍受人們關(guān)注的重要材料,由于它具有優(yōu)異的物理性能,因此它在航空航天、汽車(chē)制造等領(lǐng)域有著廣泛而重要的應(yīng)用。在Ti-Al合金的設(shè)計(jì)和應(yīng)用中,往往需要對(duì)其有關(guān)力熱性能和電子結(jié)構(gòu)有較深入的了解和掌握,因此“Ti-Al金屬間化合物的力熱性能及其能帶計(jì)算”論文具有重要的理論意義與價(jià)值。本文針對(duì)Ti-Al合金中的TiAl、TiAl_2、TiAl_3、Ti_3Al金屬間化合物的有關(guān)力熱性能和能帶,采用基于密度泛函理論的第一性原理以及Materials Studio軟件中的CASTEP軟件包進(jìn)行了理論計(jì)算。在計(jì)算過(guò)程中,首先利用廣義梯度近似(GGA)中的PBE方法,對(duì)晶體的結(jié)構(gòu)進(jìn)行了幾何優(yōu)化,得出了平衡晶格常數(shù)。在此基礎(chǔ)上,利用生成熱和結(jié)合能相應(yīng)的公式,計(jì)算得到了四種金屬間化合物的生成熱、結(jié)合能的具體數(shù)值。利用廣義梯度近似(GGA)中的PW91方法對(duì)Ti-Al合金的各個(gè)相的彈性系數(shù)進(jìn)行計(jì)算。以及對(duì)電子能帶和電子態(tài)密度曲線(xiàn)進(jìn)行了計(jì)算,并對(duì)計(jì)算結(jié)果進(jìn)行了理論分析。計(jì)算結(jié)果表明:在上述四種金屬間化合物中,由生成熱、結(jié)合能的計(jì)算結(jié)果比較得出,在Ti-Al合金的四個(gè)相中Ti_3Al的合金化形成能力最強(qiáng),而且結(jié)構(gòu)也最穩(wěn)定,通過(guò)對(duì)彈性系數(shù)的計(jì)算結(jié)果分析得出四種相的各種彈性系數(shù),其中Ti_3Al相呈韌性,且抗變形能力最強(qiáng),剛性也最強(qiáng),體現(xiàn)出良好的綜合力學(xué)性能。通過(guò)能帶、態(tài)密度的計(jì)算與分析得出,上述四種合金都屬于金屬性材料,但是TiAl_3相的金屬性較其另三種材料弱一些。其結(jié)果與其他學(xué)者實(shí)驗(yàn)及理論研究的結(jié)果基本相符。本文的計(jì)算結(jié)果為相關(guān)的理論及應(yīng)用研究提供了有益的參考。
[Abstract]:Ti-Al alloy is a kind of important material which has been paid more attention to. Because of its excellent physical properties, Ti-Al alloy is widely used in aeronautics and astronautics. Automobile manufacturing and other fields have a wide range of important applications. In the design and application of Ti-Al alloys, it is often necessary to have a deeper understanding of their mechanical and thermal properties and electronic structure. Therefore, the paper "Ti-Al Intermetallics and their Energy Band calculation" is of great theoretical significance and value. This paper focuses on TiAlAlTiAl2 in Ti-Al alloys. The mechanical and thermal properties and energy bands of TiAl3AlTi3Al intermetallic compounds. The first principle based on density functional theory and the CASTEP software package in Materials Studio software are used to carry out theoretical calculation. Firstly, the PBE method in the generalized gradient approximation (GGA) is used to optimize the structure of the crystal, and the equilibrium lattice constant is obtained. On this basis, the corresponding formulas of heat of formation and binding energy are used. The heat of formation of four intermetallic compounds was calculated. Specific values of binding energy. Generalized gradient approximation (GGA). The PW91 method is used to calculate the elastic coefficients of each phase of Ti-Al alloy, and the electron band and density of state curves are calculated. The calculated results show that the heat of formation and binding energy are compared among the above four intermetallic compounds. Among the four phases of Ti-Al alloy, the forming ability of Ti_3Al is the strongest and the structure is the most stable. The elastic coefficients of the four phases are obtained by the analysis of the elastic coefficient. Among them, the Ti_3Al phase is ductile, with the strongest resistance to deformation and the strongest rigidity, which reflects the good comprehensive mechanical properties. The calculation and analysis of the energy band and density of states show that. The above four alloys are all metallic materials. However, the gold properties of the TiAl_3 phase are weaker than those of the other three materials. The results are in good agreement with the experimental and theoretical results of other scholars. The calculated results in this paper are useful for the relevant theoretical and applied research. For reference.
【學(xué)位授予單位】：沈陽(yáng)工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TG146.23

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本文編號(hào)：1486441