本文選題：金屬玻璃 + 玻璃形成能力　； 參考：《南京航空航天大學(xué)》2017年碩士論文

【摘要】：非晶形成的微觀結(jié)構(gòu)影響因素一直是非晶態(tài)材料領(lǐng)域的研究熱點。其中CuZr二元金屬玻璃,成分簡單而具有強玻璃形成能力(GFA),人們對其微觀結(jié)構(gòu)進(jìn)行了大量研究。自由體積作為金屬玻璃的一種獨特結(jié)構(gòu)參量廣受關(guān)注,但是關(guān)于自由體積與GFA關(guān)聯(lián)性的研究很少。另外,在CuZr基合金中,摻雜元素所引起的微觀結(jié)構(gòu)變化同樣影響非晶的形成能力,對此人們也進(jìn)行了大量研究。但關(guān)于微摻雜元素與母合金具有正混合熱的體系,其GFA增強的微觀結(jié)構(gòu)機理尚不夠清晰。在本文中,選擇了CuZr和CuZrNb金屬玻璃體系,從二元到三元,利用同步輻射技術(shù)結(jié)合計算模擬對非晶形成的結(jié)構(gòu)影響因素進(jìn)行了詳細(xì)的研究。為了研究CuZr二元金屬玻璃體系中自由體積和GFA之間的關(guān)聯(lián)性,本文發(fā)展了一種用于探測金屬玻璃中自由體積信息的新方法。我們發(fā)現(xiàn)自由體積的尺寸對非晶形成能力具有顯著的影響。在具有GFA局部極大值的Cu64Zr36成分的微觀結(jié)構(gòu)中,計算得到的自由體積也呈現(xiàn)局部極大值,具有一一對應(yīng)關(guān)系。金屬玻璃的自由體積被認(rèn)為與機械性能密切相關(guān),從自由體積角度研究非晶的形成,有利于進(jìn)一步探索微觀結(jié)構(gòu)與宏觀性能的關(guān)系。此外,我們系統(tǒng)地研究了具有正混合熱的CuZrNb金屬玻璃體系,關(guān)注摻雜元素Nb引起結(jié)構(gòu)變化從而導(dǎo)致GFA增強的現(xiàn)象。進(jìn)行同步輻射X射線衍射和擴展X射線吸收精細(xì)結(jié)構(gòu)實驗,并對數(shù)據(jù)進(jìn)行擬合得到微觀結(jié)構(gòu)模型,再采用Voronoi分形方法進(jìn)行解析。發(fā)現(xiàn)在微量Nb元素(1-2 at.%)摻雜的CuZr合金體系中,Nb和Zr原子之間的電子軌道雜化導(dǎo)致原子對間距的縮短。進(jìn)一步發(fā)現(xiàn)類二十面體局域結(jié)構(gòu)的含量增加以及溶質(zhì)原子Nb的分布更加彌散。上述因素均有利于增大原子空間堆積效率并形成短程到中程有序結(jié)構(gòu),從而導(dǎo)致金屬玻璃的結(jié)構(gòu)更穩(wěn)定及GFA的相應(yīng)增強。在正混合熱的合金體系中,本工作為尋找具有高GFA的金屬玻璃成分提供了理論依據(jù)。
[Abstract]:The factors affecting the microstructure of amorphous materials have been a hot topic in the field of amorphous materials. Due to its simple composition and strong glass-forming ability, CuZr binary metallic glass has been studied for its microstructure. As a unique structural parameter of metallic glass, free volume has attracted much attention, but the correlation between free volume and GFA is seldom studied. In addition, the microstructure changes caused by doping elements also affect the ability of amorphous formation in CuZr based alloys. However, the microstructure mechanism of GFA reinforcement in the system with microdoped elements and master alloy with positive mixing heat is not clear enough. In this paper, CuZr and CuZrNb metallic glass systems are selected, from binary to ternary, the influence factors of amorphous structure are studied in detail by synchrotron radiation technique combined with computer simulation. In order to study the relationship between free volume and GFA in CuZr binary metallic glass system, a new method for detecting free volume information in metallic glass is developed. We found that the size of free volume has a significant effect on the amorphous formation ability. In the microstructure of the Cu64Zr36 component with GFA local maximum, the calculated free volume also presents a local maximum, with a one-to-one correspondence. The free volume of metallic glass is considered to be closely related to mechanical properties. Studying the formation of amorphous from the angle of free volume is beneficial to further explore the relationship between microstructure and macroscopic properties. In addition, we have systematically studied the CuZrNb metallic glass system with positive mixing heat. We pay attention to the phenomenon that the doping element NB leads to the structural change, which leads to the enhancement of GFA. The fine structure experiments of synchrotron radiation X-ray diffraction and extended X-ray absorption were carried out. The microstructure model was obtained by fitting the data and then analyzed by Voronoi fractal method. It is found that the electron orbital hybridization between NB and Zr atoms in the CuZr alloy system doped with trace NB element at 1-2 at. leads to the shortening of the pair spacing. It is further found that the local structure of icosahedron increases and the distribution of solute atoms NB becomes more dispersed. The above factors are beneficial to increase the stacking efficiency of atomic space and form the ordered structure from short range to middle range, which leads to a more stable structure of metallic glass and the corresponding enhancement of GFA. In the alloy system with positive mixing heat, this work provides a theoretical basis for finding the composition of metallic glass with high GFA.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG139.8

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 汪衛(wèi)華;;非晶態(tài)物質(zhì)的本質(zhì)和特性[J];物理學(xué)進(jìn)展;2013年05期

2 寇生中;鄭寶超;李娜;黃文軍;陳延;索紅莉;;不同元素?fù)诫s對Zr基非晶形成能力及力學(xué)性能的影響[J];金屬功能材料;2011年02期

3 冼鼎昌;;同步輻射的現(xiàn)狀和發(fā)展[J];中國科學(xué)基金;2005年06期

相關(guān)博士學(xué)位論文 前1條

1 曾橋石;金屬玻璃在壓力下多形態(tài)的研究[D];浙江大學(xué);2010年

，

本文編號：1872130