本文選題：TC4合金　切入點(diǎn)：多層DLC薄膜　出處：《重慶理工大學(xué)》2017年碩士論文

【摘要】：本文以TC4合金為研究對象,首先,利用非平衡磁控濺射技術(shù)制備了具有Cr、Ti和Si過渡層的類金剛石(Diamond-like carbon,DLC)薄膜,探究了過渡層對DLC薄膜結(jié)構(gòu)和性能的影響,考察了反應(yīng)磁控濺射參數(shù)(基底偏壓、沉積氣壓、甲烷流量和濺射功率)與DLC薄膜結(jié)構(gòu)、力學(xué)和摩擦學(xué)性能的關(guān)聯(lián);其次,以不同基底偏壓下制備的DLC薄膜為基礎(chǔ),利用有限元方法模擬了不同膜層順序(偏壓調(diào)控的軟硬薄膜)、調(diào)制周期、調(diào)制比例對多層DLC薄膜承載能力的影響;最后,依據(jù)有限元模擬的結(jié)果,實(shí)驗(yàn)制備了多層DLC薄膜,通過測試薄膜力學(xué)及摩擦學(xué)性能,研究了多層薄膜的承載能力。主要結(jié)論如下:a.過渡層基本不改變DLC薄膜的結(jié)構(gòu),不同過渡層DLC薄膜的內(nèi)應(yīng)力與各材料之間的線膨脹系數(shù)有關(guān),Si/DLC薄膜具有最低的內(nèi)應(yīng)力(~0.44GPa),Cr/DLC薄膜具有最高的臨界載荷(~25.42N);基底偏壓對DLC薄膜結(jié)構(gòu)、力學(xué)和摩擦學(xué)性能影響最大,隨基底偏壓的升高,薄膜的石墨化程度加重,硬度、楊氏模量和內(nèi)應(yīng)力逐漸降低;偏壓-800V時(shí)薄膜具有最高的結(jié)合強(qiáng)度(~25.32N),且呈現(xiàn)了較低的摩擦系數(shù)(0.05)和較長的磨損壽命。b.不同膜層順序雙層DLC薄膜系統(tǒng)的應(yīng)力/應(yīng)變分布相似,最大徑向壓應(yīng)力出現(xiàn)在壓頭底部薄膜表面,最大的剪切應(yīng)力出現(xiàn)在遠(yuǎn)離對稱軸薄膜內(nèi)部,塑性應(yīng)變僅出現(xiàn)在基底;軟-1000V/硬-800V和軟-1000V/硬-600V薄膜系統(tǒng)具有較低的徑向應(yīng)力、剪切應(yīng)力、等效應(yīng)力和彈/塑性應(yīng)變;調(diào)制周期的增加不僅改變了系統(tǒng)的應(yīng)力/應(yīng)變分布,而且大大降低了應(yīng)力最值,超過2周期應(yīng)力最值逐漸升高;隨調(diào)制比例(即硬薄膜厚度)的增加,徑向應(yīng)力最值逐漸降低,剪切應(yīng)力最值先增加后降低,等效應(yīng)力最值逐漸增加;綜合分析有限元模擬的結(jié)果,膜層順序(軟-1000V/硬-600V、軟-1000V/硬-800V和軟-1000V/硬-400V)、調(diào)制周期(2、3和4周期)和調(diào)制比例(1:1、1:2和1:3)薄膜系統(tǒng)具有較高的承載能力。c.多層結(jié)構(gòu)的引入提高了DLC薄膜的承載性能,相對于單層DLC薄膜,多層DLC薄膜具有更高的臨界載荷和承載能力。不同結(jié)構(gòu)多層DLC薄膜實(shí)驗(yàn)研究與有限元模擬結(jié)果基本一致,軟-1000V/硬-600V、軟-1000V/硬-800V、軟-1000V/硬-400V薄膜系統(tǒng)摩擦失效載荷分別為11、17、10N;調(diào)制周期的增加大大提高了薄膜與基底的結(jié)合強(qiáng)度(~31N),3周期薄膜系統(tǒng)硬度最高(~18.68GPa),2、3、4周期薄膜系統(tǒng)摩擦失效載荷分別為14、17、10N;調(diào)制比例對多層薄膜的硬度和臨界載荷影響不大,軟硬膜厚比1:2系統(tǒng)具有最低的內(nèi)應(yīng)力(~0.86GPa)且呈現(xiàn)了穩(wěn)定且較低的摩擦系數(shù),1:1、1:2、1:3薄膜系統(tǒng)摩擦失效載荷分別為17、14、10N。
[Abstract]:In this paper, TC4 alloy was used as the research object. Firstly, Diamond-like carbon DLC thin films with Cr-Ti and Si transition layers were prepared by unbalanced magnetron sputtering technique. The effect of transition layer on the structure and properties of DLC films was investigated.The relationships between reactive magnetron sputtering parameters (substrate bias, deposition pressure, methane flux and sputtering power) and the structure, mechanical and tribological properties of DLC films were investigated.The effects of modulation period and modulation ratio on the load-carrying capacity of multilayer DLC thin films were simulated by finite element method. Finally, according to the results of finite element simulation, multilayer DLC thin films were fabricated experimentally.By testing the mechanical and tribological properties of the multilayer film, the bearing capacity of the multilayer film was studied.The main conclusions are as follows: a.The structure of DLC thin film is not changed by the transition layer. The internal stress of DLC thin film in different transition layer is related to the linear expansion coefficient between different materials. The Si / DLC film has the lowest internal stress and the highest critical load is 0.44 GPA / DLC thin film, and the substrate bias voltage has the highest critical load on the structure of DLC film.The influence of mechanical and tribological properties was the greatest. With the increase of substrate bias, the graphitization degree of the film increased, hardness, Young's modulus and internal stress gradually decreased.The film has the highest bonding strength (25.32 NV) and the lower friction coefficient (0.05) and the longer wear life (.b.) at the bias voltage of -800V.The distribution of stress / strain in different film sequences is similar. The maximum radial compressive stress appears on the surface of the film at the bottom of the head, the maximum shear stress occurs in the thin film far from the symmetry axis, and the plastic strain appears only on the substrate.The soft -1000V / hard-800V and soft-1000V / hard-600V thin film systems have lower radial stress, shear stress, equivalent stress and elastic-plastic strain, and the increase of modulation period not only changes the stress / strain distribution of the system, but also greatly reduces the stress maximum.With the increase of modulation ratio (that is, the thickness of hard film), the maximum value of radial stress decreases gradually, the maximum value of shear stress increases first and then decreases, and the maximum value of equivalent stress increases gradually.The results of finite element simulation show that the thin film systems have high load-carrying capacity (soft -1000V / hard-600V, soft-1000V / hard-800V and soft--1000V / hard-400V) and modulation ratios of 1: 1: 1: 2 and 1: 3).The introduction of multilayer structure improves the bearing capacity of DLC thin films. Compared with monolayer DLC thin films, multilayer DLC thin films have higher critical load and bearing capacity.The experimental results of multilayer DLC thin films with different structures are in good agreement with the results of finite element simulation.杞，

本文編號：1703480