The effects of chemistry variations on hot cracking susceptibility of Haynes® 282® for aerospace applications

Hot cracking susceptibility of Haynes (R) 282 (R) with varying amount of C (0.05-0.09 wt%), Mn (0.03-0.12 wt %), Si (0.03-0.16), B (0.005-0.006 wt%) and Zr (0-0.01) are investigated. Synergistic role of C and B is found on solidification and heat affected zone (HAZ) liquation cracking susceptibility. High amount of C and B promote formation of eutectic constituents during final stages of solidification and promote crack healing by backfilling effect. When C and B are added in low amount the crack healing does not occur due to the absence of eutectic consituents therefore cracking extent increases. Thermodynamics simulations indicate C and B tie up to MC carbides and M3B2 borides during solidification. Scanning Electron Microscopy and Nanoscale secondary ion mass spectrometry analysis reveal C and B to be present both in solid solution and in form of precipitates to Ti-Mo rich carbides and Mo rich borides, respectively. In HAZ, these phases promote liquation cracking where cracking extent correlates to the amount carbides and borides. Lower C and B is found to reduce the liquation cracking in the HAZ. Furthermore, a high temperature homogenization heat treatment at 1190 degrees C excarbates the cracking by dissolving the borides and releasing B to the grain boundaries. (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

The hot cracking susceptibility of Haynes 282 alloy with varying amounts of C, Mn, Si, B, and Zr was investigated. The study found that the synergistic role of C and B affects the susceptibility to solidification and heat-affected zone liquation cracking. High amounts of C and B promote the formation of eutectic constituents during solidification and facilitate crack healing. Thermodynamic simulations showed that C and B combine with MC carbides and M3B2 borides during solidification. Analysis revealed that C and B are present in both solid solution and precipitates. In the heat-affected zone, these phases promote liquation cracking, and the extent of cracking correlates with the amount of carbides and borides. Lower amounts of C and B were found to reduce liquation cracking. A high-temperature homogenization heat treatment exacerbated cracking by dissolving borides and releasing B to the grain boundaries.