Paper Title:
Crack-Free Welding of IN 738 by Linear Friction Welding
  Abstract

Inconel 738 (IN 738), like other precipitation-hardened nickel-base superalloys that contain a substantial amount of Al and Ti, is very difficult to weld due to its high susceptibility to heat-affected zone (HAZ) cracking during conventional fusion welding processes. The cause of this cracking, which is usually intergranular in nature, has been attributed to the liquation of various phases in the alloy, subsequent wetting of the grain boundaries by the liquid and decohesion across one of the solid-liquid interfaces due to on-cooling tensile stresses. In the present work, crack-free welding of the alloy was obtained by linear friction welding (LFW), notwithstanding the high susceptibility of the material to HAZ cracking. Gleeble thermomechanical simulation of the LFW process was carefully performed to study the microstructural response of IN 738 to the welding thermal cycle. Correlation between the simulated microstructure and that of the weldments was obtained, in that, a significant grain boundary liquation was observed in both the simulated specimens and actual weldments due to non-equilibrium reaction of second phase particles, including the strengthening gamma prime phase. These results show that in contrast to the general assumption of LFW being an exclusively solid-state joining process, intergranular liquation is possible during LFW. However, despite a significant occurrence of liquation in the alloy, no HAZ cracking was observed, which can be partly related to the nature of the imposed stress during LFW

  Info
Periodical
Edited by
M. Heilmaier
Pages
446-453
DOI
10.4028/www.scientific.net/AMR.278.446
Citation
O. T. Ola, O. A. Ojo, P. Wanjara, M. C. Chaturvedi, "Crack-Free Welding of IN 738 by Linear Friction Welding", Advanced Materials Research, Vol. 278, pp. 446-453, 2011
Online since
July 2011
Export
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Hai Peng Jin, Jia Rong Li, Shi Zhong Liu
Abstract:The effects of high temperature exposure simulating service conditions on stress rupture properties were studied for the second generation...
1249
Authors: Gang Wang, Wen Ru Zhao, Yan Dong Liu, Chun Yan Wang, Yan Dong Wang, Liang Zuo
Abstract:In recent years, there has been an increasing interest in magnetic shape memory alloys (MSMAs) due to their unique ability to produce very...
2188
Authors: Kumkum Banerjee, Michel Perez, Matthias Militzer
Abstract:Non-isothermal austenite grain growth kinetics under the influence of several combinations of Nb, Ti and Mo containing complex precipitates...
809
Authors: Sheng Yin Song, De Li Gao, Chun Feng, Zhi Yi Liu
Chapter 5: Inorganic and Materials
Abstract:Mechanical properties and microstructural evolution of an Al-Cu-Mg-Ag alloy during thermal exposure at elevated temperature were...
671