Durejko Tomasz, Łazińska Magdalena, Dworecka-Wójcik Julita, Lipiński Stanisław, Varin Robert A, Czujko Tomasz
Department of Advanced Materials and Technologies, Military University of Technology, 2 Gen. Sylwestra Kaliskiego Street, 00-908 Warsaw, Poland.
Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Materials (Basel). 2019 Apr 26;12(9):1366. doi: 10.3390/ma12091366.
A Tribaloy family of alloys (CoMoCrSi) are characterized by a substantial resistance to wear and corrosion within a wide range of temperatures. These properties are a direct result of their microstructure including the presence of Laves phase in varying proportions. Tribaloy T-800 exhibits the highest content of Laves phase of all other commercial Tribaloy alloys, which provides high hardness and wear resistance. On the other hand, a large content of the Laves phase brings about a high sensitivity to brittle fracture of this alloy. The main objective of this work was a development of the Tribaloy T-800 coatings on the Ni-based superalloy substrate (RENE 77), which employs a Laser Engineered Net Shaping (LENS) technique. Technological limitations in this process are susceptibility of T-800 to brittle fracture as well as significant thermal stresses due to rapid cooling, which is an inherent attribute of laser techniques. Therefore, in this work, a number of steps that optimized the LENS process and improved the metallurgical soundness of coatings are presented. Employing volume and local substrate pre-heating resulted in the formation of high quality coatings devoid of cracks and flaws.
一种Tribaloy合金族（CoMoCrSi）的特点是在很宽的温度范围内具有很强的耐磨和耐腐蚀性能。这些性能是其微观结构的直接结果，包括不同比例的Laves相的存在。Tribaloy T-800在所有其他商用Tribaloy合金中Laves相含量最高，这使其具有高硬度和耐磨性。另一方面，大量的Laves相导致该合金对脆性断裂高度敏感。这项工作的主要目标是在镍基高温合金基体（RENE 77）上制备Tribaloy T-800涂层，采用激光工程净成形（LENS）技术。该工艺的技术限制在于T-800易发生脆性断裂以及由于快速冷却产生的显著热应力，这是激光技术的固有特性。因此，在这项工作中，提出了一些优化LENS工艺并提高涂层冶金质量的步骤。采用整体和局部基体预热导致形成无裂纹和缺陷的高质量涂层。
