發(fā)布時間：2018-06-22 23:56

  本文選題：薄膜 + 孿晶��； 參考：《南京大學》2015年碩士論文

【摘要】：金屬薄膜由于具有優(yōu)異的綜合性能被廣泛應用在微機電系統(tǒng)中,其中力學性能直接影響微機電系統(tǒng)的服役壽命。傳統(tǒng)的材料強化機制主要是在材料內部引入各種缺陷阻礙位錯運動來實現(xiàn),包括固溶強化、彌散強化和細晶強化等,但這些途徑不可避免地會影響材料的塑性形變能力,導致其韌性降低。研究發(fā)現(xiàn),在材料中引入納米孿晶結構,提高材料強度的同時保證其韌性不受影響,并且發(fā)現(xiàn)孿晶的形成表現(xiàn)出很強的尺度依賴性。然而目前關于納米孿晶的形成機制和尺度效應的研究主要是關于平行孿晶,在實驗過程中除平行孿晶以外,經(jīng)�？梢杂^察到多重孿晶(如二重(即V型孿晶)、三重、四重和五重孿晶),但是對于多重孿晶的形成機制、尺度依賴性及其對材料性能的改善仍然存在著許多爭議�；�于以上考慮,本文以制備Cu薄膜、Ag薄膜以及Ag/Cu多層膜為研究對象,采用直流磁控濺射法,通過改變退火溫度制備了一系列Cu、Ag薄膜以及具有不同調制周期的Ag/Cu多層膜。利用X射線衍射、掃描電子顯微鏡和透射電子顯微鏡等方法表征薄膜的微觀結構,并利用納米壓痕法表征薄膜的硬度。研究了退火處理后Cu薄膜和Ag薄膜中V型孿晶的尺度效應和形成機制,以及沉積態(tài)和退火態(tài)Ag/Cu多層膜中力學性能與多重孿晶之間的關系。主要結論如下：1.通過對不同退火溫度金屬Cu薄膜的研究發(fā)現(xiàn),V型孿晶數(shù)量隨著晶粒尺寸的減小,先增加后降低,在晶粒尺寸為40m附近達到最大,表現(xiàn)出明顯的反晶粒尺寸效應。2.通過對不同退火溫度金屬Ag薄膜的研究同樣發(fā)現(xiàn)V型孿晶數(shù)量遵從反晶粒尺寸效應,但是由于Ag的層錯能非常低,造成與Cu薄膜中V型孿晶的尺度效應存在差異,其峰值晶粒尺寸出現(xiàn)在60 nm左右,且V型孿晶的最大晶粒尺寸(155 nm)大于Cu薄膜(121 nm)。3.從能量角度上提出一種新的多重孿晶形成機制,即V型孿晶是由退火驅動的晶界遷移和晶粒轉動協(xié)同產生的,并且其形成過程包括形核和增殖兩個階段。4.基于Cu薄膜和Ag薄膜中V型孿晶在臨界晶粒尺寸時出現(xiàn)最大密度,設計了一種調制比為2的Ag/Cu多層膜,并對不同調制周期的沉積態(tài)和退火態(tài)多層膜進行研究,發(fā)現(xiàn)沉積態(tài)Ag/Cu多層膜的硬度隨尺度的變化表現(xiàn)出非單調性,在調制周期為45 nm時硬度達到最大值3.42 GPa。當對調制周期為45 nrn的Ag/Cu多層膜進行100℃退火處理后,其硬度值相比沉積態(tài)時進一步提高到3.59 GPa,這是由于退火后Ag/Cu多層膜中出現(xiàn)大量多重孿晶,多重孿晶界可以阻擋不同方向上的不全位錯。這為制備超高強度多層膜的設計提供了新思路。
[Abstract]:Metal films have been widely used in microelectromechanical systems because of their excellent comprehensive properties. Mechanical properties directly affect the service life of microelectromechanical systems. The traditional material strengthening mechanism mainly introduces various defects to prevent dislocation motion in the material, including solid solution strengthening, dispersion strengthening and fine grain strengthening, but these are the main reasons. The approach inevitably affects the plastic deformation ability of the material and leads to the reduction of its toughness. It is found that the nano twin structure is introduced in the material, the strength of the material is increased and the toughness is not affected, and the formation of the twins shows a strong scale dependence. However, the formation mechanism and the ruler of the nanocrystalline twins are present. The study of the degree effect is mainly about parallel twins. In addition to parallel twins in the experiment, multiple twins (such as double (V type twins), three weight, four weight and five twins) are often observed. However, there are still many controversies on the formation mechanism of multiple twins, the scale dependence and the improvement of the material properties. Considering the preparation of Cu films, Ag films and Ag/Cu multilayer films, a series of Cu, Ag films and Ag/Cu multilayer films with different modulation periods were prepared by DC magnetron sputtering, and the microscopes of the thin films were characterized by X ray diffraction, scanning electron microscopy and transmission electron microscopy. The microhardness of the thin films was characterized by nano indentation. The scale effect and formation mechanism of V twin in Cu and Ag films after annealing, and the relationship between mechanical properties and multiple twins in the deposited and annealed Ag/Cu multilayer films were investigated. The main conclusions are as follows: 1. through the metal Cu films at different annealing temperatures It is found that the number of V twins increases first and then decreases with the size of grain size, and reaches the maximum in the vicinity of the grain size of 40m, showing an obvious reverse grain size effect..2. also finds that the number of V twins follows the anti grain size effect through the study of different annealing temperature metal Ag thin films, but because the Ag's stacking fault energy is very low The scale effect is different from the V type twin in the Cu film, the peak grain size appears at about 60 nm, and the maximum grain size of the V type twin is greater than that of Cu film (121 nm).3., which is a new multiple twin formation mechanism from the energy point of view, that is, the V twin crystal is produced by annealing driven grain boundary migration and grain rotation. The formation process consists of two stages of nucleation and proliferation, which is based on the maximum density of the V twin in the critical grain size of the V type twins in the.4. and Ag films. A Ag/Cu multilayer film with a modulation ratio of 2 is designed, and the deposition and annealed multilayer films of different modulation periods are studied, and the hardness of the deposited Ag/Cu multilayer films is found. When the modulation period is 45 nm, the hardness reaches the maximum value of 3.42 GPa.. When the Ag/Cu multilayer film with a modulation period of 45 NRN is annealed at 100 C, the hardness value is further increased to 3.59 GPa compared to the deposited state, which is due to a large number of multiple twins and multiple twins in the Ag/ Cu multilayer film after annealing. Grain boundaries can block incomplete dislocations in different directions. This provides a new idea for the design of ultrahigh strength multilayers.
【學位授予單位】：南京大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG14;TB383.2

【相似文獻】

相關期刊論文 前10條

1 吳元康;;灰口鑄鐵在沖擊高壓下的變化—Ⅱ.鐵素體孿晶的形成[J];金屬科學與工藝;1986年01期

2 周耐根,周浪;生長銅膜中孿晶形成與出現(xiàn)幾率的分子動力學模擬[J];金屬學報;2004年09期

3 倪川皓;王富恥;徐強;馬壯;王揚衛(wèi);;超高速碰撞下體心立方純鐵的變形孿晶[J];北京理工大學學報;2011年08期

4 武鳳,朱靜;石墨/鎂基復合材料中的殘余應變、位錯及孿晶[J];金屬學報;1998年05期

5 陳先華;;孿晶對Cu的力學和電學性能影響的研究進展[J];材料工程;2011年09期

6 方敦輔,徐涌泉,相德(钅久),譚禮同;LEC-InP晶體中的孿晶現(xiàn)象[J];稀有金屬;1990年05期

7 石德珂;楊桂應;;1Cr18Ni9Ti不銹鋼的變形[J];金屬熱處理學報;1992年01期

8 高英俊;王江帆;羅志榮;盧強華;劉瑤;;晶體相場方法模擬納米孿晶結構[J];計算物理;2013年04期

9 單海權;張躍飛;毛圣成;張澤;;電沉積納米孿晶Ni中五次孿晶的電子顯微分析[J];金屬學報;2014年03期

10 季長濤;陳咨偉;劉云旭;;形變誘發(fā)納米孿晶對0Cr22Mn17MoNbN鋼的強化作用[J];金屬熱處理;2013年03期

相關會議論文 前1條

1 周浪;周耐根;李殿國;;<111>生長銅膜中孿晶形成的原子機理[A];2002年材料科學與工程新進展（下）——2002年中國材料研討會論文集[C];2002年

相關重要報紙文章 前1條

1 柯新瑋;我國發(fā)現(xiàn)提高材料綜合強韌性新途徑[N];上�？萍紙�;2009年

相關博士學位論文 前10條

1 郭曉倩;基于多晶塑性模型的多晶體材料大變形行為研究[D];中國礦業(yè)大學;2015年

2 蘇鈺;新型高強度和高塑性孿晶誘發(fā)塑性鋼的研究[D];上海大學;2012年

3 秦洪;多晶純鈦室溫下不同應變速率塑性變形的孿生形變機制研究[D];重慶大學;2014年

4 王s，

本文編號：2054785