TiAlN涂层强流脉冲电子束表面改性研究

发布时间：2018-04-25 09:43

本文选题：TiAlN + 强流脉冲电子束　；参考：《沈阳理工大学》2017年硕士论文

【摘要】：TiAlN涂层强流脉冲电子束(High Current Pulsed electron Beam,HCPEB)表面处理技术的应用引起人们的重视,但对轰击处理后涂层的成分、晶体结构和应力状态的研究较少。本课题通过实验分析TiAlN涂层HCPEB前后的组织结构和力学性能的变化,并结合基于密度泛函理论的第一性原理计算研究涂层成分、晶体结构和应力状态对材料力学性能的影响。对TiAlN涂层进行不同工艺参数的HCPEB处理,采用SEM对处理前后涂层的表面和断面形貌进行观察,并利用EDS对其进行成分分析。采用XRD对轰击前后TiAlN涂层进行物相检测,通过X射线外标法测量轰击前后TiAlN的晶格常数,采用2θ—sin2ψ法对HCPEB轰击前后的TiAlN涂层残余应力测量,运用纳米压痕技术,对HCPEB轰击前后的TiAlN涂层进行力学性能测量。结果发现经HCPEB处理后涂层中的柱状晶晶界变得模糊甚至消失,轰击前后涂层中Ti、Al原子比基本不变;经HCPEB处理后没有新物相产生,对比未处理TiAlN涂层的晶格常数(4.1780?)经HCPEB轰击后晶格常数都不同程度的减小,处理后晶格常数变化从4.1627~4.1749?不等;未处理涂层的残余压应力为243.77 MPa,经HCPEB轰击后TiAlN涂层的压应力在90.98~532.65 MPa之间变化,而且随着HCPEB沉积总能量的增加呈现升高-降低-升高-降低-再升高的趋势;未处理TiAlN涂层的纳米硬度为28.174 GPa,经HCPEB轰击后,随着电子束沉积能量的增加呈增加趋势,工艺参数为11.6KV-80A-20 times时涂层的力学性能最好。第一性原理计算结果表明当晶格常数在4.1627~4.1749?变化时时,NaCl型的Ti_4Al_4N_8可以稳定存在。力学性能的计算结果表明,不同晶格常数下Ti_4Al_4N_8的杨氏模量变化规律与实验结果一致,HCPEB轰击导致TiAlN涂层晶格常数改变是材料的力学性能发生变化的主要原因。对Ti_3AlN_4模型的计算结果可知,稳定态Ti_3AlN_4的弹性模量为421.77 GPa,当Ti、Al原子出现空位时,弹性模量变化非常小,但N原子位置空位的出现使Ti_3AlN_4的弹性模量下降到82.92 GPa。
[Abstract]:The application of TiAlN coating strong current pulse electron beam (High Current Pulsed electron Beam, HCPEB) surface treatment technology has aroused people's attention. But there are few studies on the composition, crystal structure and stress state of the coating after bombardment. The change of microstructure and mechanical properties of TiAlN coating HCPEB before and after HCPEB is analyzed by experiment, and the conclusion is made. Based on the first principle of density functional theory, the influence of coating composition, crystal structure and stress state on the mechanical properties of the material is studied. The HCPEB treatment of TiAlN coating with different process parameters is carried out by using SEM to observe the surface and section morphology of the coating before and after treatment, and the composition of the coating is analyzed with EDS. The XRD pair is used. The TiAlN coating was detected before and after bombardment, and the lattice constant of TiAlN was measured before and after bombardment by X ray external standard. The residual stress of TiAlN coating before and after the bombardment of HCPEB was measured by 2 theta sin2 method, and the nano indentation technology was used to measure the mechanical properties of the TiAlN coating before and after the bombardment of HCPEB. The results were found in the coating after HCPEB treatment. The columnar crystal boundaries become blurred and even disappearing. The Ti and Al atoms in the coating are almost invariable before and after bombardment; no new phase is produced after HCPEB treatment. The lattice constant of the untreated TiAlN coating (4.1780?) decreases to varying degrees after the bombardment of HCPEB, and the lattice constant changes from 4.1627~4.1749? The residual compressive stress of the layer is 243.77 MPa, the compressive stress of the TiAlN coating changes between the 90.98~532.65 MPa after the HCPEB bombardment, and the tendency to increase with the increase of the total energy of HCPEB deposition - decrease - increase - decrease and then increase; the nano hardness of the untreated TiAlN coating is 28.174 GPa, after the HCPEB bombardment, the energy of the electron beam is deposited with the electron beam. The increase shows an increasing trend and the mechanical properties of the coating are the best when the process parameters are 11.6KV-80A-20 times. The first principle calculation results show that when the lattice constant changes in 4.1627~4.1749? NaCl type Ti_4Al_4N_8 can be stable. The calculation results of mechanical properties show that the young's modulus change of Ti_4Al_4N_8 under the different lattice constants. It is consistent with the experimental results that the change of the lattice constant of the TiAlN coating is the main reason for the change of the mechanical properties of the material by HCPEB bombardment. The calculation results of the Ti_3AlN_4 model show that the modulus of elasticity of the stable state Ti_3AlN_4 is 421.77 GPa. When Ti, the Al atom appears vacant, the modulus of elasticity changes very little, but the appearance of the position of the N atom position is caused by the presence of the N atom position. The modulus of elasticity of Ti_3AlN_4 drops to 82.92 GPa.

【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG661

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