本文關鍵詞： 納孔方鈷礦CoSb3 分子動力學 力學行為　出處：《武漢理工大學》2015年碩士論文　論文類型：學位論文

【摘要】：熱電材料是利用Seebeck效應實現熱能與電能之間相互轉換的新型功能材料,利用熱電材料制作的器件無污染、安全可靠,具有廣闊的應用前景。方鈷礦CoSb3熱電材料是我國以及國際上高度重視研究的熱電材料,在方鈷礦CoSb3熱電材料中引入納米孔洞可以顯著降低材料的熱導率從而提高其熱電性能,納孔方鈷礦材料被認為是很有應用前景的熱電材料,但是納米孔洞的引入會降低材料的力學性能,從而限制方鈷礦材料的工業(yè)化應用。鑒于此,本文以納孔方鈷礦熱電材料為研究對象,利用課題組前期建立的方鈷礦原子間相互作用勢函數,發(fā)展納孔方鈷礦熱電材料單軸拉伸和壓縮力學行為的分子動力學方法,分別研究單軸拉伸和壓縮應力場下納孔形狀和孔隙率對方鈷礦材料本征力學行為的影響規(guī)律,從原子尺度上研究并揭示納孔方鈷礦材料單軸拉伸和壓縮應力場下的結構破壞機理,探索具備高力學性能納孔方鈷礦材料的孔隙率、納孔形狀的匹配關系,為發(fā)展高力學性能的納孔方鈷礦熱電材料提供理論指導。納米柱孔方鈷礦CoSb3的力學性能研究結果表明,外部加載條件如溫度和應變率對力學性能影響很小,但是孔隙率對拉伸/壓縮力學性能影響很大。相對于環(huán)境溫度和孔隙率,納米柱孔主宰著單晶CoSb3的缺陷形式,拉伸/壓縮力學性能隨著孔隙率的增加逐漸降低,彈性模量與孔隙率滿足反比例函數關系式。極限應力隨著孔隙率的增加線性降低。納米球孔方鈷礦CoSb3力學性能研究結果表明,球孔力學性能優(yōu)于柱孔CoSb3的力學性能,這主要是由于柱孔CoSb3更多的應力集中區(qū)域導致的。隨著孔隙率的增加,所有的力學量依次降低。球形納孔方鈷礦CoSb3表現出相同的溫度軟化效應。這種軟化效應隨著拉伸應變的增加逐漸加劇。應變率基本對納米球孔方鈷礦CoSb3的拉伸/壓縮彈性模量和拉伸/壓縮極限應力無影響。
[Abstract]:Thermoelectric material is a new type of functional material which uses Seebeck effect to realize the conversion between heat energy and electric energy. The device made from thermoelectric material has no pollution and is safe and reliable. The CoSb3 thermoelectric material of galactic cobalt ore is a kind of thermoelectric material which is paid great attention to in our country as well as in the world. The introduction of nano-pores into the CoSb3 thermoelectric materials can significantly reduce the thermal conductivity of the materials and improve their thermoelectric properties. The nanoporous galactite materials are considered to be very promising thermoelectric materials. However, the introduction of nano-pores will reduce the mechanical properties of the materials, thus limiting the industrial application of galactic cobalt materials. In view of this, this paper takes the nanocrystallite pyroelectric materials as the research object. The molecular dynamics method of uniaxial tensile and compressive mechanical behavior of nanocrystallite pyroelectric materials was developed by using the potential function of interaction between the atoms of galactic cobalt ores established by our research group. The effect of the shape and porosity of nanpore on the intrinsic mechanical behavior of galactic acid materials under uniaxial tensile and compression stress was studied respectively. In this paper, the failure mechanism of nanocrystallite materials under uniaxial tensile and compressive stress was studied and revealed from atomic scale, and the porosity and the matching relation of nanoporous shape of nanoporous cobalt ore materials with high mechanical properties were explored. It provides theoretical guidance for the development of high mechanical properties nanocrystallite pyroelectric materials. The mechanical properties of nanocrystallite CoSb3 are studied. External loading conditions such as temperature and strain rate have little effect on mechanical properties, but porosity has a great effect on tensile / compressive mechanical properties, compared with ambient temperature and porosity. Nano-columnar pore dominates the defect form of single crystal CoSb3, and the tensile / compressive mechanical properties decrease with the increase of porosity. The relationship between elastic modulus and porosity is inversely proportional. The ultimate stress decreases linearly with the increase of porosity. The results of CoSb3 mechanical properties study show that the ultimate stress decreases linearly with the increase of porosity. The mechanical properties of spherical pore are better than that of columnar pore CoSb3, which is mainly due to the more stress concentration area of CoSb3. All the mechanical quantities decreased in turn. The CoSb3 of spherical nanoporous cobalt ore showed the same temperature softening effect. This softening effect gradually increased with the increase of tensile strain. The tensile / compressive elastic modulus and tensile / compression ultimate stress of oSb3 are not affected.
【學位授予單位】：武漢理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB34

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相關期刊論文 前1條

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