Advanced microstructural characterisation of cast ATI 718Plus®—effect of homogenisation heat treatments on secondary phases and repair welding behaviour
Journal article, 2020
24 h dwell time pseudo-hip homogenisation heat treatments at 1120, 1160 and 1190 °C with the as-cast microstructure. Scanning
electron microscopy (SEM), X-ray diffraction (XRD) on electrolytically extracted powder and transmission electron microscopy
(TEM) were used to identify Nb-rich secondary phases in interdendritic areas as the C14 Laves phase and Nb(Ti) MC-type
carbides. All homogenisation heat treatments but the 1120 °C 4-h condition dissolve the Laves phase. A repair welding operation
was simulated by linear groove multi-pass manual gas tungsten arc welding (GTAW). The Laves phase containing microstructures
resulted in lower total crack length for heat affected zone cracking. Constitutional liquation of Nb(Ti) MC-type carbides is
observed as a liquation mechanism in Laves-free microstructure, while thick liquid film formation due to the Laves eutectic
melting could reduce the formation of weld cracks in microstructures containing the Laves phase.
weldability
cracking
repair
nickel alloys
GTAwelding
ATI 718Plus
Author
Fabian Hanning
Chalmers, Industrial and Materials Science, Materials and manufacture
Abdul Khaliq Khan
University of Manitoba
Joel Andersson
University West
Olanrewaju Ojo
University of Manitoba
Welding in the World, Le Soudage Dans Le Monde
0043-2288 (ISSN) 18786669 (eISSN)
Vol. 64 3 523-533Subject Categories
Manufacturing, Surface and Joining Technology
Other Materials Engineering
Metallurgy and Metallic Materials
Areas of Advance
Materials Science
DOI
10.1007/s40194-020-00851-0