| 电弧离子镀制备(Ti,Al)N薄膜的残余应力的研究 | |
| Alternative Title | Investigation on Residual Stresses in (Ti,Al)N Films Deposited by Arc Ion Plating |
| 赵升升 | |
| Subtype | 博士 |
| Thesis Advisor | 孙超 |
| 2009-07-28 | |
| Degree Grantor | 中国科学院金属研究所 |
| Place of Conferral | 金属研究所 |
| Degree Discipline | 材料加工工程 |
| Keyword | 电弧离子镀 残余应力 力学性能 (Ti Al)n 硬质薄膜 |
| Abstract | 硬质薄膜的应用广泛，其力学性能对膜/基系统的服役行为影响很大，是研究热点。本论文发展了一种硬质薄膜残余应力测试的新方法，并且重点研究了电弧离子镀(Ti,Al)N薄膜沉积工艺对其残余应力的影响，对(Ti,Al)N薄膜的残余应力沿层深分布的机理进行了讨论。 以基片弯曲法为基础，针对硬质薄膜的自身特点，进行改进创新，提出了利用剥层曲率半径法测量薄膜的残余应力及其在薄膜中的分布，并组建了一套精密的光学系统用于测定试片的曲率变化。研究了工艺参数对电弧离子镀(Ti,Al)N薄膜的力学性能、组织结构、及化学成分的影响。 通过对薄膜的逐层剥离，测量试片的曲率半径变化，测定了残余应力沿薄膜深度的分布规律；电弧离子镀制备的(Ti,Al)N薄膜的残余应力实测结果表明，残余应力沿层深分布形态为“钟罩形”，在膜/基界面附近应力较小，随着膜厚增大，应力逐渐增加，在近表面层应力出现最大值，在表面层区域，应力值下降。 脉冲偏压工艺对薄膜的力学性能有显著影响。当偏压较高时，离子在薄膜制备过程中对试片表面的轰击能量较强，薄膜的硬度较大，平均残余应力较大；当偏压较低时，薄膜的硬度较低，平均残余应力较小。偏压变化对残余应力的沿层深分布有明显作用。随着偏压的升高，残余应力分布的峰值随之增大。根据偏压对薄膜力学性能的影响，采用变化脉冲偏压的工艺制备了性能优异的(Ti,Al)N硬质薄膜，薄膜的硬度比高偏压下沉积的薄膜的硬度略有降低，残余应力显著下降，且应力沿层深分布均匀，膜/基结合力显著提高；利用循环变化脉冲偏压工艺制备了大厚度(Ti,Al)N薄膜。 氮气分压对薄膜的力学性能有显著影响。当氮气分压较低时，薄膜中含有较多TiAl合金相，金属键的大量存在使硬质薄膜的硬度较低，平均残余应力较低，但残余应力沿层深分布较均匀，膜/基结合力较高；当氮气分压增大时，薄膜中的共价键增多，薄膜硬度明显增大，平均残余应力增大，但应力沿层深分布出现峰值，膜/基结合力下降。根据氮气分压对薄膜力学性能的影响，采用变化氮气分压的工艺制备了性能优异的(Ti,Al)N硬质薄膜，其硬度比高氮气分压下沉积的薄膜的硬度略低，结合力显著提高，平均残余应力下降，且沿层深分布均匀。利用梯度改变氮气分压的工艺制备了厚度超过60μm的(Ti,Al)N梯度涂层，在保持高硬度的同时，有效的改善了残余应力沿层深分布形态，提高了薄膜的综合力学性能。 |
| Other Abstract | The extensive use of hard films has stimulated considerable interest in their properties. It is significant to research the relation between the preparation process and films’ mechanical properties. In this dissertation, at first, a new method was set up to determine the residual stresses of hard films; subsequently, the effects of the technology process were investigated on mechanical properties of (Ti,Al)N films by arc ion plating. We put forward to a new method to test the residual stresses in hard films layer by layer, which is based on the substrate curvature method and aiming at hard films. And, we designed an accurate optical system to test the change of the curvature of the samples. The detailed results of this work were shown as follows. Above all, the feasibility of the residual stress measurement was proven and the errors of it were estimated through the successful measurement of the depth distribution of the residual stresses in the (Ti,Al)N films. The compressive residual stresses at the GPa level existed in the (Ti,Al)N film deposited by Arc Ion Plating, and the depth distribution of the residual stresses has a trend of “bell” with the peak appearing in the middle of the film. The thicker the films, the higher the average residual stresses of total film thickness. The effects of the bias voltage on mechanical properties of the films are obvious. Increasing bias voltage causes a rise in compressive stresses and hardness in (Ti,Al)N films. Periodically alternating the bias voltage during deposition can smoothen out the distribution of stresses, enhance the adhesion of films and maintain the high hardness. Based on optimized parameters, a film of 7.57 μm in thickness was created directly on the substrate with the stresses significantly relieved. Following the same procedure, gradient films and multilayer films with large thickness can be prepared, due to the slow accumulation of stresses. Alternating bias voltage during deposition is an effective means to create gradient and uniform stress distributions, which in turn benefit the improvement of film properties. Nitrogen partial pressure is another important factor for the mechanical properties of hard films. It was found that the deposition rate decreases, film hardness increases and adhesion strength decreases when N2 partial pressure is increased from 0.2Pa to 0.8Pa. Based on the above results, the technology process of changed N2 partial pressure was adopted during deposition of the (Ti,Al)N films. The residual stresses of the films notably decreased and the distribution profiles of the stresses in the films got more even than the films at high N2 partial pressure. Finally, the thick gradient (Ti,Al)N coating (about 68μm) with a Ti interlayer was successfully deposited on a substrate by continuously increasing nitrogen flow rate during deposition. Such an achievement can be attributed to the gradient distribution of element, hardness and stresses across the coating thickness. |
| Pages | 125 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/17242 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 赵升升. 电弧离子镀制备(Ti,Al)N薄膜的残余应力的研究[D]. 金属研究所. 中国科学院金属研究所,2009. |
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