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TIALMET - Surface modification of gamma-TiAl alloys and its influence on mechanical properties and phenomena under high temperature conditions

TIALMET - γ-TiAl合金的表面改性及其对高温条件下机械性能和现象的影响

基本信息

批准号：
380687629
负责人：
Dr.-Ing. Stefan Guth, since 1/2021
金额：
--
依托单位：
Institut für Angewandte Materialien - Werkstoffkunde (IAM-WK)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/380687629?language=en
关键词：
TIALMET Surface modification gamma TiAl

项目摘要

The aim of the project is to obtain new and detailed knowledge about the influence of surface modifications on microstructure, oxidation resistance and mechanical properties of gamma-titanium aluminides. Within the project several surface modifications will be developed in close coop-eration by the partners, (i) deposition of protective AlSi and TiAlCrY coatings by two different methods, chemical vapor deposition (CVD) and physical vapor deposition (PVD), (ii) an additional surface modification by pre-oxidation under varying partial pressures of oxygen to foster the formation of a stable and TiO2-free protective scale (alpha-alumina), and (iii) shot peen-ing to introduce compressive stresses into the surfaces to improve the mechanical (fatigue) properties of the TiAl alloy. One novelty of the project is the deposition of AlSi coatings by CVD and PVD and its applica-tion as bond coats for TBCs. The ability of AlSi as well as TiAlCrY coatings to form a slow-growing and stable alpha-alumina scale on gamma-TiAl alloys creates a potential for their application in TBC systems where bonding and compatibility between the 7YSZ topcoat and bond coat is of great importance. However, data on interfacial phenomena and their evolution in such TBC systems, and the influence of these protective coatings on mechanical properties of the base alloy are missing. Fundamental analyses of surface modifications such as pre-oxidation relying on the growth of a protective alumina scale under various environmental conditions as well as mechanical treatments by shot peening will lead to modified surfaces with improved properties, evaluated by new techniques such as determination of the brittle to ductile transition with drastically reduced sample numbers.The project aims to give for the first time systematic results on the influence of surface modi-fications on the oxidation and fatigue properties of TiAl at different temperatures. Moreover, introduction of compressive stresses targets to improve the fatigue life, which was never tried before for coatings on gamma-TiAl alloys. All goals can only be achieved by close collaboration between the Polish and German partners, since the sub-tasks, surface modification methods used, and tests rely on the work from each other and could not be performed without this international collaboration.

该项目的目的是获得有关表面改性对γ-钛铝化物的微观结构、抗氧化性和机械性能的影响的新的详细知识。在该项目中，合作伙伴将密切合作开发几种表面改性，（i）通过两种不同的方法，化学气相沉积（CVD）和物理气相沉积（PVD）沉积保护性AlSi和TiAlCrY涂层，（ii）通过在不同的氧分压下预氧化进行额外的表面改性，以促进形成稳定且不含TiO 2的保护层（α-氧化铝），和（iii）喷丸以将压缩应力引入表面以改善TiAl合金的机械（疲劳）性能。本课题的新奇之处在于用CVD和PVD方法沉积AlSi涂层及其作为热障涂层的粘结层。AlSi以及TiAlCrY涂层在γ-TiAl合金上形成缓慢生长且稳定的α-氧化铝氧化皮的能力为其在TBC系统中的应用创造了潜力，其中7 YSZ顶涂层和粘结涂层之间的粘结和相容性非常重要。然而，在这样的TBC系统的界面现象和它们的演变，以及这些保护涂层对基体合金的机械性能的影响的数据是失踪。对表面改性的基本分析，如在各种环境条件下依赖于保护性氧化铝氧化皮生长的预氧化以及通过喷丸的机械处理，将导致具有改进性能的改性表面，通过新技术进行评估，例如用大量减少的样品数量确定脆韧性转变。该项目旨在首次给出关于影响的系统结果。研究了表面改性对TiAl在不同温度下的氧化和疲劳性能的影响。此外，引入压应力的目标是提高疲劳寿命，这是以前从未尝试过的γ-TiAl合金上的涂层。只有通过波兰和德国合作伙伴之间的密切合作才能实现所有目标，因为子任务，所使用的表面改性方法和测试都依赖于彼此的工作，如果没有这种国际合作，就无法完成。