發(fā)布時(shí)間：2018-04-17 20:19

  本文選題：金屬玻璃 + 固溶體合金�。� 參考：《大連理工大學(xué)》2017年博士論文

【摘要】：本論文將針對(duì)金屬玻璃和固溶體合金的成分根源進(jìn)行研究。這兩類合金在特定成分下會(huì)具有特殊的性能,這些特定成分都是經(jīng)過長(zhǎng)期大量的實(shí)驗(yàn)探索而得,人們迫切需要理解其成分背后的結(jié)構(gòu)根源,從而建立有效的成分設(shè)計(jì)理論,以指導(dǎo)合金研發(fā)。鑒于這些合金均呈現(xiàn)近程有序結(jié)構(gòu),本課題組前期工作利用團(tuán)簇加連接原子模型實(shí)現(xiàn)了對(duì)近程有序結(jié)構(gòu)的描述,經(jīng)驗(yàn)式地提出了合金具有特定的"第一近鄰團(tuán)簇加若干連接原子"成分式,但是在成分式的獲得上一直存在物理基礎(chǔ)不明確、經(jīng)驗(yàn)推斷過多等缺點(diǎn),包括第一近鄰的準(zhǔn)確定義、團(tuán)簇的選擇以及連接原子的定量確定。本論文將針對(duì)上述關(guān)鍵問題進(jìn)行研究,通過引入電子的Friedel振蕩和球周期,完善了描述近程序結(jié)構(gòu)的團(tuán)簇加連接原子模型,提出了類似于分子式的合金化學(xué)結(jié)構(gòu)單元,并實(shí)現(xiàn)了其定量計(jì)算。由此,本工作揭示了金屬玻璃和固溶體合金的成分根源,推出了統(tǒng)一的成分式規(guī)則,發(fā)展了合金成分設(shè)計(jì)的理論基礎(chǔ)。具體的工作內(nèi)容涵蓋以下四個(gè)方面:(1)首先引入電子的Friedel振蕩解決第一近鄰多面體團(tuán)簇的定義問題。第一近鄰的確定一直缺乏物理機(jī)制,尤其是團(tuán)簇第一近鄰原子分布在多個(gè)殼層上時(shí),團(tuán)簇的截?cái)嗑嚯x無(wú)法確定。本論文通過引入電子的Friedel振蕩機(jī)制和原子密堆判據(jù),給出了截?cái)嗑嚯x的明確定義,并指出團(tuán)簇的最近鄰殼層被Friedel振蕩勢(shì)函數(shù)中第一個(gè)最小值的范圍所限制。團(tuán)簇中"中心原子-最外層原子"和"中心原子-最內(nèi)層原子"的距離分別為rL和rS利用Friedel振蕩得到rL/rs的上限為1.5。隨后在硬球原子密堆的前提下,進(jìn)一步將rL/rS與原子半徑比和團(tuán)簇表面覆蓋構(gòu)型建立關(guān)聯(lián),給出不同情況下rL/rS的比值。將rL/rS與測(cè)得的rS相乘,最終得到團(tuán)簇的截?cái)嗑嚯x,并且在常見的團(tuán)簇構(gòu)型中得到驗(yàn)證。(2)其次,解決了進(jìn)入金屬玻璃成分式的團(tuán)簇的精確選擇問題。金屬玻璃相關(guān)的合金相中通常含有多個(gè)非等效的原子占位,以任一個(gè)原子占位為心都可以定義出一個(gè)團(tuán)簇,從這些團(tuán)簇中選取出最具代表性的主團(tuán)簇是需要解決的關(guān)鍵問題。本論文強(qiáng)調(diào)了主團(tuán)簇的兩個(gè)重要的特征:球周期性和團(tuán)簇間距,同時(shí)也是金屬玻璃的兩個(gè)結(jié)構(gòu)特征。利用這兩個(gè)特征給出了二元塊體金屬玻璃相關(guān)合金相中主團(tuán)簇的嚴(yán)格定義,并利用這些主團(tuán)簇解釋了二元塊體金屬玻璃成分,包括Cu-Zr、Cu-Hf、Ni-Nb、Ni-Ta、Al-Ca和Pd-Si體系。(3)提出了描述固溶體近程序的化學(xué)結(jié)構(gòu)單元并實(shí)現(xiàn)了其定量計(jì)算。認(rèn)為接近熔點(diǎn)的熔體與隨后形成的固溶體之間存在類似的近程序結(jié)構(gòu)遺傳。通過將團(tuán)簇共振模型引入到固溶體結(jié)構(gòu)的中程序描述中,指出理想滿足原子間作用的團(tuán)簇加連接原子成分式就是類似于分子式的化學(xué)結(jié)構(gòu)單元,而作為核心近程序結(jié)構(gòu)從液態(tài)遺傳到固溶體態(tài),并得到了結(jié)構(gòu)單元的計(jì)算公式,Z=c ·ρa(bǔ)·r13,其中c為常數(shù),ρa(bǔ)為原子密度(單位體積原子個(gè)數(shù)),r1為團(tuán)簇半徑。利用這個(gè)公式計(jì)算得到了典型FCC結(jié)構(gòu)工業(yè)合金中的化學(xué)結(jié)構(gòu)單元,包括二元Cu基工業(yè)合金、Ni基單晶高溫合金以及無(wú)Co馬氏體時(shí)效不銹鋼,其結(jié)果與最常用的合金牌號(hào)吻合,從而揭示出工業(yè)合金的成分根源在于具有特定結(jié)構(gòu)的化學(xué)結(jié)構(gòu)單元。(4)建立了具有焊料背景的Sn基共晶點(diǎn)的雙團(tuán)簇模型。本課題組之前的工作提出了共晶液體的雙團(tuán)簇模型,即共晶液體由兩個(gè)穩(wěn)定的液體結(jié)構(gòu)單元構(gòu)成,這兩個(gè)結(jié)構(gòu)單元分別來(lái)自兩個(gè)共晶相,結(jié)構(gòu)單元可以用理想金屬玻璃的團(tuán)簇式表示。Sn基共晶點(diǎn)多靠近β-Sn一側(cè),不能用上述雙團(tuán)簇模型解釋。共晶點(diǎn)中Sn含量較高,因此可以假設(shè)構(gòu)成共晶液體的兩個(gè)結(jié)構(gòu)單元都基于β-Sn結(jié)構(gòu),這樣就可以利用上一章中固溶體結(jié)構(gòu)單元的計(jì)算方法進(jìn)行團(tuán)簇式的計(jì)算。首先計(jì)算出β-Sn結(jié)構(gòu)中的化學(xué)結(jié)構(gòu)單元為[Sn-Sn10]Sn5,即配位數(shù)為10的團(tuán)簇加上5個(gè)連接原子。然后將另一種元素當(dāng)作溶質(zhì),根據(jù)公式Z=c·ρa(bǔ)·r13 計(jì)算出具體的團(tuán)簇式形式。利用雙團(tuán)簇成分式解析了簡(jiǎn)單Sn基二元共晶點(diǎn),包括Sn-(Ag,Au,Mg,Pb,Zn,Bi)。最后根據(jù)這些雙團(tuán)簇式,解析了典型Sn基共晶釬料成分,指出多組元Sn基共晶釬料中微合金化元素的添加一般是通過對(duì)基礎(chǔ)二元成分進(jìn)行整數(shù)個(gè)原子的替換實(shí)現(xiàn)的,從而為Sn基共晶釬料的成分設(shè)計(jì)提供了一種新的方法。
[Abstract]:This paper will research on metal glass and solid solution alloy composition of roots. The two kinds of alloy will have special properties in specific components, these specific components is through long-term experiments and exploration, the root of people need to understand the source behind the components, so as to establish the effective theory of composition design to guide, alloy research and development. In view of these alloys showed a short-range ordered structure, ourprevious work using cluster plus glue atom model for short-range ordered structure description, empirical formula proposed alloy has specific "nearest neighbor clusters with several atomic components, but the connection" in component there has been on the physical basis is not clear, too much experience and other shortcomings, including the accurate definition of the first nearest neighbor, determine the cluster selection and quantitative connection of the atoms. This paper will address. Research on the key problems, through the introduction of electronic Friedel oscillation and ball cycle, improve the structure of the program described near cluster plus glue atom model, put forward the chemical structure of alloy unit similar to the molecular formula, and realizes the quantitative calculation. Thus, this work reveals a metal glass and solid solution alloys the root, launched a unified composition rules, the development of the theoretical basis of alloy composition design. The main content covers the following four aspects: (1) the definition of the problem first introduced Friedel electron oscillation solution of first neighbor polyhedron clusters. The first neighbor has been the lack of physical mechanism, especially the first nearest neighbor cluster the distribution of atoms in multiple shell, cut distance cluster cannot be determined. This paper introduced the electronic Friedel oscillation mechanism and atomic packing criterion, given truncation distance defined, And pointed out that the cluster nearest neighbor shell is restricted by the first minimum value in the range of Friedel oscillation potential function. The cluster "central atom - the outermost atomic" and the "central atom of the innermost atomic distance were rL and rS by Friedel rL/rs of the upper limit of 1.5. oscillation was then in the hard sphere packing density the atom under the premise of further rL/rS with atomic radius ratio and cluster configuration of surface coverage, given the ratio under different conditions of rL/rS. RL/rS and rS measured by multiplying the truncation distance obtained clusters, and verified in the cluster configuration in common (2). Secondly, to solve the the precise selection problem into clusters. The composition of metallic glass alloy metal glass phase usually contains a number of non equivalent atoms occupying, with any of the atoms occupying heart can define a cluster, from these clusters in selecting the most The main cluster representative is the key problem to be solved. This paper emphasizes two important characteristics of the main clusters: Ball periodicity and cluster spacing, and two structural features is given by the metallic glass. The two features a strict definition of two yuan bulk metallic glass alloy related main phase the cluster, and use the main cluster explained two yuan bulk metallic glass components, including Cu-Zr, Cu-Hf, Ni-Nb, Ni-Ta, Al-Ca and Pd-Si system. (3) proposed chemical structure description of the unit solid solution near program and achieve its quantitative calculation. That close to the melting point and then melt the formation of solid solution are similar in genetic structure between programs through the cluster resonance model is introduced into the structure of solid solution in the program description, pointed out that the ideal meet cluster interaction and connection type atomic elements is similar to the molecular formula of chemical structure The unit, which is the core in the program structure from the liquid solid solution to the genetic body, and the calculate formula of the structural unit, Z=c p a R13, where C is a constant, a refers to the atomic density (number of atoms per unit volume), R1 as the cluster radius. Using this formula to calculate the chemical structure the typical structure of industrial unit FCC alloy, including two Cu based alloy industry, and Ni based single crystal superalloy Co maraging stainless steel, the most commonly used alloy anastomosis, so as to reveal the composition of alloy is the root of industrial chemical structure units with specific structure. (4) two clusters the model established with Sn based solder background of the eutectic point. The eutectic liquid cluster model of our group work, which is composed of two stable eutectic liquid liquid structure unit, the two units were from two eutectic phase, 緇撴瀯鍗曞厓鍙互鐢ㄧ悊鎯抽噾灞炵幓鐠冪殑鍥㈢皣寮忚〃紺，

本文編號(hào)：1765122