納米晶Cu的制備與力學性能的研究
發(fā)布時間：2019-04-23 17:03
【摘要】：近幾年來，我們發(fā)現(xiàn)了大量關(guān)于納米晶金屬力學性能的研究。納米晶金屬的力學性能表征和測試手段也是層出不窮。隨著納米晶金屬制備技術(shù)的不斷進步，材料的晶粒尺寸、結(jié)構(gòu)和純度都可以實現(xiàn)精密控制和不斷優(yōu)化，這就為納米晶金屬力學性質(zhì)的研究與發(fā)展提供了很好的技術(shù)支持，基于這一背景，我們通過實驗合成不同晶粒尺寸范圍和結(jié)構(gòu)的納米晶Cu并對其力學性質(zhì)進行研究，從而進一步分析納米晶金屬在不同條件下的變形機理，最終為納米晶金屬的應(yīng)用提供理論支撐。為了達到上述目標，我們的具體工作如下： 1.不同晶粒尺寸的納米晶Cu分別由磁控濺射和電刷鍍技術(shù)制備。我們利用實驗材料，設(shè)備，并進行了實驗參數(shù)的優(yōu)化，從而實現(xiàn)了納米晶Cu晶粒尺寸的控制。對于電刷鍍制備納米晶Cu，通過控制電流密度和Cu離子的濃度，可以控制晶粒尺寸的范圍非常廣，，制備出了不同晶粒尺寸的納米晶Cu試樣，并可以控制孿晶的生長。對于磁控濺射制備納米晶Cu，通過改變?yōu)R射功率，濺射氣壓，可以把晶粒控制在更小的范圍內(nèi)。不同納米材料的微觀結(jié)構(gòu)和晶粒尺寸是通過透射電子顯微鏡進行觀察的。 2.我們將用電刷鍍制備好的~59nm，~120nm和~200nm的納米晶Cu進行拉伸試驗，通過對不同拉伸速率下的應(yīng)力應(yīng)變曲線的分析，我們可以知道納米晶Cu的彈性，塑性與應(yīng)變速率與晶粒尺寸的關(guān)系，通過對拉伸后形貌與斷口形貌的分析可知：納米晶Cu的斷口有明顯的韌窩形貌，為塑性斷裂。韌窩的形貌與斷裂的方式與晶粒尺寸與應(yīng)變速率有著緊密的聯(lián)系。 3.我們對晶粒尺寸從~22nm到~210nm的納米晶Cu進行深度敏感納米壓痕實驗，利用Berkovich壓頭并將應(yīng)變速率控制在0.004s-1，0.04s-1和0.4s-1。我們利用激光共聚焦顯微鏡觀察壓痕后的形貌并測量變形后的深度變化。我們建立了三個實驗參數(shù)(hb，hi和hd)來表征在應(yīng)變速率和晶粒尺寸影響下的變形程度。從而探究應(yīng)變速率和晶粒尺寸和壓痕后形貌之間的關(guān)系。為納米壓痕計算材料的硬度與彈性模量提供理論指導(dǎo)。 4.我們對~10nm和~23nm Cu利用納米壓痕儀進行蠕變測試。應(yīng)變速率控制從4×10-1s-1變到4×10-3s-1。通過分析我們知道：小晶粒尺寸試樣在高應(yīng)變速率下蠕變應(yīng)變速率要大。是由于在這種條件下，加載階段會存儲大量的位錯，從而影響保載階段的蠕變行為。另外，通過將實驗所得蠕變應(yīng)變速率和理論蠕變應(yīng)變速率進行比較，可以看出~10nm Cu所存儲的位錯將會很快被吸收，從而使得晶界滑移和Coble蠕變控制蠕變過程。對于~23nm Cu，蠕變過程則是由起初的位錯運動和之后的晶界滑移所主導(dǎo)。
[Abstract]:In recent years, we have found a lot of research on the mechanical properties of nanocrystalline metals. The mechanical properties and testing methods of nanocrystalline metals are also emerging in endlessly. With the development of the preparation technology of nanocrystalline metals, the grain size, structure and purity of the materials can be controlled and optimized, which provides a good technical support for the research and development of the mechanical properties of nanocrystalline metals. Based on this background, we synthesized nanocrystalline Cu with different grain sizes and structures by experiments and studied its mechanical properties, so as to further analyze the deformation mechanism of nanocrystalline metals under different conditions. Finally, it provides theoretical support for the application of nanocrystalline metals. In order to achieve the above-mentioned objectives, our specific work is as follows: 1. Nanocrystalline Cu with different grain sizes were prepared by magnetron sputtering and brush plating. In order to control the grain size of nanocrystalline Cu, the experimental materials and equipment are used to optimize the experimental parameters. By controlling the current density and the concentration of Cu ions, nanocrystalline Cu, samples with different grain sizes were prepared by controlling the current density and the concentration of Cu ions, and the growth of twins was also controlled. Nanocrystalline Cu, prepared by magnetron sputtering can be controlled in a smaller range by changing sputtering power and sputtering pressure. The microstructure and grain size of different nano-materials are observed by transmission electron microscope (TEM). 2. The nano-crystalline Cu of ~ 59 nm, 120 nm and ~ 200nm prepared by brush plating has been tested by tensile test. By analyzing the stress-strain curves at different tensile rates, we can know the elasticity of nanocrystalline Cu. The relationship between plasticity and strain rate and grain size. Through the analysis of tensile morphology and fracture morphology, it can be seen that the fracture surface of nanocrystalline Cu has obvious dimple morphology, which is plastic fracture. The morphology and fracture mode of dimples are closely related to grain size and strain rate. 3. The depth sensitive nano indentation experiment of nanocrystalline Cu with grain size from ~ 22nm to ~ 210nm was carried out. The strain rate was controlled at 0.004s / 1, 0.04s / 1 and 0.4s / 1.by using the Berkovich indenter and the strain rate was controlled at 0.004s / 1, 0.04s / 1 and 0.4s / 1 respectively. We use laser confocal microscope to observe the morphology of indentation and measure the depth change after deformation. Three experimental parameters (hb,hi and hd) were established to characterize the deformation degree under the influence of strain rate and grain size. The relationship between strain rate, grain size and indentation morphology was investigated. It provides theoretical guidance for calculating hardness and elastic modulus of nano-indentation materials. 4. We tested the creep of ~ 10nm and ~ 23nm Cu by nano indentation apparatus. Strain rate control from 4 脳 10-1s-1 to 4 脳 10-3 sv. Through the analysis, we know that the creep strain rate of small grain size specimen is larger at high strain rate. The reason is that under this condition, a large number of dislocations will be stored in the loading phase, which will affect the creep behavior of the loading phase. In addition, by comparing the experimental creep strain rate with the theoretical creep strain rate, it can be seen that the dislocation stored by ~ 10nm Cu will be absorbed quickly, which makes grain boundary slip and Coble creep control the creep process. The creep process of ~ 23nm Cu, is dominated by the initial dislocation motion and the subsequent grain boundary slip.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;O614.121
本文編號：2463638
[Abstract]:In recent years, we have found a lot of research on the mechanical properties of nanocrystalline metals. The mechanical properties and testing methods of nanocrystalline metals are also emerging in endlessly. With the development of the preparation technology of nanocrystalline metals, the grain size, structure and purity of the materials can be controlled and optimized, which provides a good technical support for the research and development of the mechanical properties of nanocrystalline metals. Based on this background, we synthesized nanocrystalline Cu with different grain sizes and structures by experiments and studied its mechanical properties, so as to further analyze the deformation mechanism of nanocrystalline metals under different conditions. Finally, it provides theoretical support for the application of nanocrystalline metals. In order to achieve the above-mentioned objectives, our specific work is as follows: 1. Nanocrystalline Cu with different grain sizes were prepared by magnetron sputtering and brush plating. In order to control the grain size of nanocrystalline Cu, the experimental materials and equipment are used to optimize the experimental parameters. By controlling the current density and the concentration of Cu ions, nanocrystalline Cu, samples with different grain sizes were prepared by controlling the current density and the concentration of Cu ions, and the growth of twins was also controlled. Nanocrystalline Cu, prepared by magnetron sputtering can be controlled in a smaller range by changing sputtering power and sputtering pressure. The microstructure and grain size of different nano-materials are observed by transmission electron microscope (TEM). 2. The nano-crystalline Cu of ~ 59 nm, 120 nm and ~ 200nm prepared by brush plating has been tested by tensile test. By analyzing the stress-strain curves at different tensile rates, we can know the elasticity of nanocrystalline Cu. The relationship between plasticity and strain rate and grain size. Through the analysis of tensile morphology and fracture morphology, it can be seen that the fracture surface of nanocrystalline Cu has obvious dimple morphology, which is plastic fracture. The morphology and fracture mode of dimples are closely related to grain size and strain rate. 3. The depth sensitive nano indentation experiment of nanocrystalline Cu with grain size from ~ 22nm to ~ 210nm was carried out. The strain rate was controlled at 0.004s / 1, 0.04s / 1 and 0.4s / 1.by using the Berkovich indenter and the strain rate was controlled at 0.004s / 1, 0.04s / 1 and 0.4s / 1 respectively. We use laser confocal microscope to observe the morphology of indentation and measure the depth change after deformation. Three experimental parameters (hb,hi and hd) were established to characterize the deformation degree under the influence of strain rate and grain size. The relationship between strain rate, grain size and indentation morphology was investigated. It provides theoretical guidance for calculating hardness and elastic modulus of nano-indentation materials. 4. We tested the creep of ~ 10nm and ~ 23nm Cu by nano indentation apparatus. Strain rate control from 4 脳 10-1s-1 to 4 脳 10-3 sv. Through the analysis, we know that the creep strain rate of small grain size specimen is larger at high strain rate. The reason is that under this condition, a large number of dislocations will be stored in the loading phase, which will affect the creep behavior of the loading phase. In addition, by comparing the experimental creep strain rate with the theoretical creep strain rate, it can be seen that the dislocation stored by ~ 10nm Cu will be absorbed quickly, which makes grain boundary slip and Coble creep control the creep process. The creep process of ~ 23nm Cu, is dominated by the initial dislocation motion and the subsequent grain boundary slip.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;O614.121
【參考文獻】
相關(guān)期刊論文 前2條
1 Muhammad Imran;Fayyaz Hussain;Muhammad Rashid;S.A.Ahmad;;Molecular dynamics study of the mechanical characteristics of Ni/Cu bilayer using nanoindentation[J];Chinese Physics B;2012年12期
2 孫世成;孫貴訓;江忠浩;季長濤;劉家安;連建設(shè);;Effects of cold rolling deformation on microstructure,hardness,and creep behavior of high nitrogen austenitic stainless steel[J];Chinese Physics B;2014年02期
相關(guān)博士學位論文 前1條
1 沈喜訓;塊體電沉積納米晶鎳及鎳鈷合金的微觀結(jié)構(gòu)和力學行為[D];吉林大學;2009年
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