Pre- and post-TLP bond solution treatments: Effects on the microstructure and mechanical properties of GTD-111 superalloy

Abstract

Abstract This paper addresses the effects of bonding time and standard solution treatment on the microstructure and mechanical properties of GTD-111 superalloy bonded by transient liquid phase (TLP) using a Ni-7.58Cr-3.42Fe-3.6Si-2.95B amorphous interlayer. In this regard, three different heat treatment cycles namely HT A, HTB and HTC were applied to separate TLP joints. In the HT-A cycle, full-solution annealing (1200 °C/4 h) of the base metal was first carried out followed by TLP bonding at 1120 °C/105 min, partial solution annealing (1120 °C/2 h) and finally aging treatment (845 °C/24 h). In the HTB cycle, the first step was TLP bonding for 105 min at 1120 °C followed by full-solution, partial solution and aging heat treatments. Finally, the HT C cycle was similar to the HT B cycle except for the TLP bonding process which was performed at 1120 °C/15 min. The results indicated that HT B treatment leads to a more uniform microstructure in the bond area and base metal compared to the microstructure obtained from HT A and HTC samples. Mechanical testing results indicated that a completely uniform hardness profile, similar to the base metal, was perceived in the bond region in the HT B sample. The highest joint shear strength among all of the samples was obtained for the HT B sample.