Heat Treatment Optimization for Nickel-based Cast Superalloy
Typ
Examensarbete för masterexamen
Program
Publicerad
2021
Författare
Ancona Orozco, David
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Nickel-based superalloys are broadly used in the aerospace industry for applications
at elevated service temperatures. Haynes 282 is a recently developed, gamma-prime
(γ
′
) strengthened, nickel-based superalloy that can be manufactured in different
ways, such as wrought methods, powder methods, and castings. An important
difference between these methods is the lower mechanical performance found in the
cast version of the alloy. A way to improve the mechanical properties of cast Haynes
282 is through a tailored heat treatment that considers the different properties of
the material and the microstructural changes required.
The objective of this thesis work was to define alternative heat treatments to improve the ductility and strength of cast Haynes 282. These proposals were based
on different studies found in literature, simulations, and microstructural analysis
performed at GKN Aerospace. The heat treatments were tested and compared with
reference values from the standard heat treatment recommended by Haynes International, and with a standard heat treatment developed by GKN. The tensile tests
were carried out at room and elevated temperature, and their results, in combination
with the microstructural analysis of the secondary phases performed in the different
heat treated samples, showed an improvement in mechanical properties from a couple of heat treatment proposals. A proposed heat treatment, labeled HT10, showed
a potential improvement of tensile strength, ductility and containment properties
at an elevated temperature of 750 °C. Haynes standard heat treatment also showed
improved properties between the two temperatures, when compared to the standard
GKN heat treatment.
Beskrivning
Ämne/nyckelord
Nickel superalloy , Haynes 282 , heat treatment , mechanical properties , microstructure , ductility , containment , cast materia , precipitation , gamma prime , carbides