Current-Assisted Diffusion Bonding of Extruded Ti-22Al-25Nb Alloy by Spark Plasma Sintering: Interfacial Microstructure and Mechanical Properties

• Published in: Journal of materials engineering and performance Vol. 27; no. 6; pp. 3035 - 3043
• Main Authors: Yang, Jianlei, Wang, Guofeng, Jiao, Xueyan, Gu, Yibin, Liu, Qing, Li, You
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2018
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Materials Science; Quality Control; Reliability; Safety and Risk; Tribology; AlNb-based alloys; diffusion bonding; mechanical property; microstructure; Ti; spark plasma sintering
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-018-3398-3

Spark plasma sintering (SPS) technology was used to current-assisted bond extruded Ti-22Al-25Nb alloy. The effects of bonding temperature (920-980 °C) and bonding time (10-30 min) on the microstructure evolution and shear strength of this alloy were investigated systematically. The temperature distribution in the specimen during the current-assisted bonding process was also analyzed by numerical simulation. It is noted that the highest temperature was obtained at the bonding interface. As the bonding temperature and bonding time increased, the voids in the interface shrank increasingly until they vanished. A complete metallurgical bonding interface could be produced at 960 °C/20 min/10 MPa, exhibiting the highest shear strength of 269.3 MPa. In addition, the shear strength of the bonded specimen depended on its interfacial microstructure. With increased bonding temperature, the fracture mode transformed from the intergranular fracture at the bonding interface to the cleavage fracture in the substrate.