Microstructure and mechanical properties in TLP joint of FeCoNiTiAl alloy and IC10 superalloy using Mn-Ni-Cr filler

A filler metal of Mn-Ni-Cr was used to transient liquid phase (TLP) bonding high-entropy alloy (HEA) of FeCoNiTiAl and Ni3Al base IC10 superalloy for 10 min - 120 min at 1150 degrees C and a pressure of 2 MPa. There was no diffusion affected zone (DAZ) existed in the bonded zone as the filler material Mn-Ni-Cr contained no conventional melting-point depressants (MDPs) of Si/B. Hence, the TLP joint was composed of two isothermally solidified zones (ISZs) and an athermally solidified zone (ASZ). The ISZ beside IC10 consisted of strip Ni(Al, Mn) phases, resulted from the diffusion of Al atoms, and only gamma-(Ni, Mn) phases formed in another ISZ adjacent to HEA base metal (BM). Moreover, sluggish diffusion of HEA can prevent the BM from dissolving and formed a straight bond line consisting of (Hf, Ta)C + Al0.89Mn1.1 compound in the interface between HEA and bonded zone. Furthermore, increase of bonding time can lead to enrichment of Al in the bonded zone and induce composition segregation during solidification. A compound of Ni(Al, Mn) + Ni3Ta formed in ASZ of joint bonded for 30 min - 120 min. Hardness results revealed that formations of Ni(Al, Mn) phases and the compounds in ASZ can cause the alternant hardness distribution of valley and peak across the joint and lead to the generation of stress concentration. Therefore, the maximum shear strength, 269.9 MPa, was achieved in the joint dwelled for a period of 10 min.

Automated summary

A filler metal of Mn-Ni-Cr was used for transient liquid phase (TLP) bonding of FeCoNiTiAl high-entropy alloy and Ni3Al base IC10 superalloy, resulting in the formation of two isothermally solidified zones (ISZs) and an athermally solidified zone (ASZ). The absence of conventional melting-point depressants (MDPs) in the filler material prevented the formation of a diffusion affected zone (DAZ) in the bonded zone.