Advanced high-temperature resistant (RT-1000 °C) aluminum phosphate-based adhesive for titanium superalloys in extreme environments. Issue 23 (1st December 2021)

• Record Type: Journal Article
• Authors: Wang, Mingchao; Li, Kun; Lu, Ruoyun; Feng, Zhaojie; Wei, Tong; Zhou, Qingjun; Zhai, Wenzheng
• Is Part Of: Ceramics international. Volume 47:Issue 23(2021)
• Page Start: 32988
• Page End: 33001
• Publication Date: 2021-12-01
• Subjects: Advanced joining -- High-temperature resistant adhesives -- Bonding mechanism -- Bonding performance -- Interfacial reaction; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.08.199
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: To facilitate the repairing and connecting processes for titanium superalloys, an advanced high-temperature resistant adhesive that can be converted to a composite of intermetallics and ceramics was prepared by modifying aluminum phosphate-based adhesive with various additives. The composition evolution of the adhesive, the structure changes in the bonding layer, the reaction process at interfaces and the fracture mode of joints are comprehensively studied to explore the bonding mechanism. The results showed that the chemical bonding based on the formation of TiSi and Ti5 Si4 started to work at 600 °C, and became the crucial bonding mechanism at higher temperatures. A diffusion reaction layer with size up to 6 μm effectively alleviated the difference of composition and performance between alloy substrate and adhesive. From RT to 900 °C, the coefficient of thermal expansion (CTE) of adhesive matched well with that of alloy substrates, and the difference of their CTE was always lower than 2 × 10 −6 k −1 . The bonding strength reached ~16 MPa after pre-treatment at 900 °C without pressure, and remained over 13 MPa within the common operating temperature range (400–600 °C) of TC4 alloys. Without any pre-treatment, the adhesive could still provide above 5 MPa in range of RT-600 °C.