Effect of bonding parameters on microstructural characteristics during TLP bonding of directionally solidified Ni-based superalloy. (December 2017)

• Record Type: Journal Article
• Authors: Kim, Jeong Kil; Park, Hae Ji; Shim, Deog Nam; Kim, Dong Jin
• Is Part Of: Journal of manufacturing processes. Volume 30(2017)
• Page Start: 208
• Page End: 216
• Publication Date: 2017-12
• Subjects: Transient liquid phase bonding -- Diffusion -- Isothermal solidification; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2017.09.024
• Languages: English
• ISSNs: 1526-6125

Abstract

Abstract: Transient liquid phase bonding (TLP) is well-known to be essential technology to repair damaged components for gas turbines. In this article, directionally solidified γ′-precipitation strengthened GTD-111 superalloy was TLP bonded using Ni-Cr-Si-B filler metal and the effect of bonding parameters on microstructure of the joints was investigated. Isothermal solidification was not completed for the joint bonded at 1150 °C for 60 min, and this joint consisted of three distinct zones: the athermal solidication zone, the isothermal solidification zone and the diffusion affected zone. A phase-free TLP joint, solidified isothermally, was attained at 1150 °C for 90 min and the crystallographic orientation of the ISZ coincided exactly with that of the base metal. Various phases of Ti were observed in the joints formed at 1170 °C and 1190 °C, indicating that temperatures higher than 1170 °C induce a reduction of the isothermal solidication rate. It was found that increase in Ti concentration and decrease in B diffusivity in the joints bonded at temperatures above 1170 °C was the main reason for this reduction.