Investigations on temperature-activated coatings for friction reduction during turning of titanium alloys

钛合金车削过程中减少摩擦的温度激活涂层的研究

• 批准号: 422345568
• 负责人: Professorin Dr.-Ing. Kirsten Bobzin
• 金额: --
• 依托单位: Institut für Oberflächentechnik (IOT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/422345568?language=en
• 关键词: Investigations; temperature; activated; coatings; friction

In the research project the oxidation and diffusion behaviour as well as the application behaviour of vanadium-containing physical vapour deposition (PVD) hard coatings on cemented carbide substrates during turning of the difficult-to-machine titanium alloy Ti6Al4V were investigated. The results showed that CrAlVN with vanadium as triboactive element enables the formation of easily shearable oxide phases at operating temperatures of ϑ = 800 °C in tribological model tests. Supplementary, the formation of friction-reducing oxide phases in the area of the cutting edge on the tool coating was proven despite the use of cooling lubricant after the machining of Ti6Al4V. However, the investigations indicate that the number of oxides formed in the cutting process is too small to cause significant tool life increases. The temperature determination of the cutting temperatures on the chip and main flank surface could not be achieved in the current project due to strong adhesive wear. Therefore, a temperature determination during turning TiAl6V4 is necessary. Initial investigations with CrAlMoN coated tools showed a friction-reducing effect already at ϑ ≤ 600 °C. In addition, an improvement in tool life was achieved, which for the first time surpassed the tool life of the uncoated substrate used as state of the art. The reduced activation temperature might be the reason for this. Therefore, the knowledge of the cutting temperature is important to correlate the diffusion and oxidation due to the machining with the observations from the model tests and thus to derive influences on the damage mechanisms during machining. This results in a considerable need for research on CrAlMoN coatings.Main aim of the proposed follow-up project is to gain knowledge on the cause-effect relationships that can lead to a reduction of tool load in the machining processes of the difficult-to-machine titanium alloy Ti6Al4V with self-lubricating CrAlMoN coatings. For this purpose, CrAlMoN coatings with varying element content are deposited, followed by a characterization of coating and composite properties. Furthermore, the oxidation and diffusion behavior as well as the friction behavior will be investigated in model tests. Moreover, the cutting temperature during the turning of titanium is measured by means of a novel temperature measurement setup. Furthermore, coated cutting tools are used in turning tests and subsequently subjected to a detailed damage analysis.

研究了硬质合金基体上含钒物理气相沉积（PVD）硬质涂层在车削难加工钛合金Ti6Al4V过程中的氧化、扩散行为以及应用行为。结果表明，以钒为摩擦活性元素的CrAlVN在摩擦学模型试验中，在800 °C的工作温度下能够形成易剪切的氧化物相。此外，尽管在加工Ti6Al4V后使用了冷却润滑剂，但已证明在刀具涂层上的切削刃区域中形成了减少摩擦的氧化物相。然而，调查表明，在切削过程中形成的氧化物的数量太少，导致显着的刀具寿命增加。由于强粘着磨损，在当前项目中无法实现切屑和主后刀面上的切削温度的温度确定。因此，在车削TiAl6V4期间的温度确定是必要的。对CrAlMoN涂层刀具的初步研究表明，在≤ 600 °C的温度下，已经具有降低摩擦的效果。此外，实现了工具寿命的改善，这是第一次超过作为最新技术水平使用的未涂覆基材的工具寿命。降低的活化温度可能是原因。因此，切削温度的知识是很重要的相关的扩散和氧化，由于从模型试验的观察，从而得出加工过程中的损伤机制的影响。因此，对CrAlMoN涂层的研究具有重要的意义。本研究的主要目的是获得CrAlMoN涂层在难加工钛合金Ti6Al4V的切削加工过程中降低刀具载荷的因果关系。为此目的，沉积具有不同元素含量的CrAlMoN涂层，然后表征涂层和复合材料性能。此外，氧化和扩散行为以及摩擦行为将在模型试验中进行研究。此外，在钛车削过程中的切削温度测量通过一种新的温度测量装置。此外，涂层刀具用于车削测试，随后进行详细的损坏分析。