TiAlN复合刀具涂层的制备及切削性能研究(论文14000字)
摘 要
本文利用多弧离子镀技术在钨钢表面沉积了TiAlN涂层，并选择最佳工艺参数制备具有TiAlN涂层的钨钢刀具。采用X射线衍射仪、扫描电镜及能谱仪、显微硬度计、划痕仪、摩擦磨损实验及切削实验研究了TiAlN涂层的组织结构、力学性能、摩擦磨损性能及其刀具的切削性能，揭示了N2流量对TiAlN涂层的结构、硬度、涂层/基体结合强度和摩擦磨损性能的影响规律，分析了具有TiAlN涂层的钨钢刀具的切削失效机理。
通过对比不同N2流量下TiAlN涂层的XRD图谱可知，在较高气压下，薄膜组织变得致密，结晶好，柱状晶明显，因此衍射峰更明显。随N2流量的逐渐增大，薄膜颗粒先增大后减小。这是因为在高的N2流量下粒子碰撞与散射现象加剧，导致小颗粒偏离轨道，到达基体表面的颗粒能量减小，颗粒的迁移速率降低，成核数量减少，颗粒粗大。随N2流量的增加，薄膜和基体的结合力呈先增后减的趋势，当氮气流量为150sccm时，TiAlN 薄膜的膜基结合力最高，达到38N，TiAlN涂层在压头的作用下形成鱼骨状的褶皱，表现出较强的脆性，并且在划痕末端出现涂层出现大块的涂层脱落，涂层的剥落形式为粘结剥落。当N2流量为150sccm时，试样表面的磨痕较窄较浅，具有更好的摩擦学性能，这是由于此时膜基结合力最强，其主要磨损机制为磨粒磨损与粘着磨损。TiAlN涂层在干摩擦条件下其摩擦系数约为0.35~0.45之间，且随N2流量的增大，试样表面涂层的摩擦磨损系数逐渐减小，表面涂层在干摩擦条件下的主要粘附大量的磨屑、氧化物与涂层剥落损伤。
以钨钢（YG6X）为基体，TiAlN涂层硬质合金刀具在切削速度为560r/min条件下进行车削不锈钢试验，研究表明，PVD涂层硬质合金的失效过程为：首先从切削刃口处的涂层开始脱落，然后涂层与基体共同磨损，在切屑的粘结作用下，涂层进一步发生剥落，基体会发生氧化磨损，最后基体在粘结磨损和氧化磨损的共同作用下快速磨损。
关键词：多弧离子镀；TiAlN涂层；显微硬度；摩擦磨损性能；切削性能
Abstract
TiAlN coating was deposited on tungsten steel surface by multi-arc ion plating technology, and the optimum process parameters were selected to prepare tungsten steel tool with TiAlN coating. Using X-ray diffraction, scanning electron microscope and energy spectrometer, micro hardness tester, scratch tester, friction and wear experiment and cutting experiment of TiAlN coatings was studied organizational structure, mechanical properties, friction and wear performance and cutting performance of a tool, reveals the N2 flow structure and hardness of TiAlN coatings, the coating/substrate bonding strength and the influence law of friction and wear performance, analyzes the cutting tungsten steel cutter with TiAlN coatings failure mechanism.
By comparing the XRD map of TiAlN coating under different N2 flows, it can be seen that, under the high pressure, the film tissues become dense, crystallized, and the columnar crystals are obvious, so the diffraction peak is more obvious. With the increase of N2 flow, the film particles increased and then decreased. This is because the particle collision under high flow of N2 and scattering phenomenon, lead to small particles off track, reach the surface of the substrate particle energy decreases, and the particle migration rate decreased, the decrease in the number of nucleation and grain bulky. With the increase of N2 flow rate, the adhesion strength of the film and substrate showed a trend of increase after decreases first and when the nitrogen flow rate is 150 SCCM, highest TiAlN film of film adhesion, thirty-eight n, TiAlN coatings under the action of pressure head form herringbone fold, showed a greater brittleness, and in the end of the scratch coating appears large peeling coating, coating spalling flake form for bonding. When N2 flow rate for 150 SCCM, grinding crack on the surface of the specimen is narrow shallow, has better tribological performance, this is because the strongest film adhesion, the main wear mechanism is abrasive wear and adhesive wear. TiAlN coating under dry friction condition between the friction coefficient of about 0.35 ~ 0.35, and with the increase of N2 flow, coating the surface of the sample coefficient of friction and wear gradually decreases, and the main adhesive coating under dry friction condition a lot of wear debris, oxide with coating spalling damage.
Tungsten steel (YG6X) as matrix, TiAlN coated carbide cutting tools in cutting speed of 560 r/min turning of stainless steel under the condition of experiment, research has shown that the failure process of the PVD coated carbide as follows: first of all, from the cutting edge of the coating began to fall off, then coating and matrix wear together, under the action of the chip bonding, coating spalling occurs, further matrix can produce oxidation wear, finally base on adhesion wear and oxidation wear under the joint action of rapid wear.
Keywords: multi-arc ion plating,TiAlN coating, microhardness, friction and abrasion performance, cutting performance.
目录
摘 要 1
Abstract 2
1 绪论 6
1.1 引言 6
1.2 多弧离子镀技术 6
1.2.1多弧离子镀的原理与特点 6
1.2.2 多弧离子镀的工艺参数 7
1.3 TiAlN涂层的研究现状 7
1.4 本课题研究的内容及意义 8
2 实验材料与实验方法 9
2.1 实验材料 9
2.2 实验方法 9
2.3 实验所用设备及仪器 11
2.4 组织分析及性能测试 13
2.4.1 XRD物相分析 13
2.4.2 金相组织观察 13
2.4.3 显微硬度测试方法 14
2.4.4 磨损性能测试方法 14
2.4.5 结合强度测试方法 14
2.4.6 削性能测试方法 15
2.5 本章小结 15
3 N2流量对TiAlN涂层组织结构的影响 16
3.1 不同N2流量下TiAlN涂层的物相分析 16
3.2 不同N2流量下TiAlN涂层的显微组织分析 16
3.3 不同N2流量下TiAlN涂层的显微硬度分析 17
3.4 本章小结 18
4 TiAlN涂层的膜基结合强度及摩擦磨损特性研究 19
4.1 TiAlN涂层的膜基结合强度及损伤机制研究 19
4.1.1 TiAlN涂层的膜基结合强度 19
4.1.2 TiAlN涂层的损伤机制研究 20
4.2 TiAlN涂层的摩擦磨损特性及磨损机理研究 20
4.2.1 TiAlN涂层的摩擦磨损特性分析 20
4.2.2 TiAlN涂层的磨损机理研究 24
4.3 本章小结 25
5 TiAlN涂层刀具的切削和摩擦学特性 26
5.1 引言 26
5.2 试验条件与方法 26
5.3 试验结果与讨论 27
5.3.1 刀具的三向力分析 27
5.3.2 刀具前刀面摩擦系数 28
5.3.3 被加工件表面粗糙度 28
5.3.4 磨损量Vb 29
5.4 磨损形貌及磨损机理研究 29
5.4.1 TiAlN涂层的刀具的磨损形态 29
5.4.2 刀具磨损机理分析 30
5.5 本章小结 31
6 结论 32
参考文献 33
致谢 35 |
