Ceena Joseph, new doctor in Engineering Materials, found a way to get stable microstructures in Ni-based superalloy Haynes 282. The screens in the background shows samples of grain structures in the superalloy after heat treatment.

New doctor on heat treatment and mechanical properties of a nickel-based superalloy

In a project together with GKN Aerospace Sweden concering weldable structures, Ceena Joseph has studied the effect of heat treatment, microstructure and mechanical properties of Haynes 282, a nickel-based superalloy.
GKN produces large houses for jet engines, which are exposed to high temperatures over and over. These high temperatures require special materials that can handle the stress in such a warm environment, such as nickel-based superalloys. Among these superalloys, the Ni-base superalloy Haynes 282 has been attracting interest due to its high-temperature properties and weldability.
During the pre-study, Ceena Joseph and her colleagues at the division of Engineering Materials, Department of Industrial and Material Science, found a need for better understanding of the heat treatment process and how to optimize it.

The fabrication strategy for critical applications such as aero engines was about to be changed from large cast parts into welded structures of forged multi-material goods. Something that required adapting the right heat treatment in order to get the right mechanical performance.

The challenge is to tailor the heat treatment to suit the multi-material structures and still be able to meet the desired property requirements.

-    This requires a profound understanding of the process-structure-property relationships for these complex alloys, says Ceena Joseph.

Her research focusses on different heat treatments, how to optimize it and the sensitivity in the treatments. For instance, what happens in the microstructure during temperature changes? Are the mechanical properties stable?

-    We have been able to understand the sensitivity of this alloy for different heat treatment conditions, which primarily occurs due to changes in its microstructural constituents. These microstructural changes affect the mechanical properties of the alloy, which can hence be tailored by heat treatment.
The research results show that, within the process variation mechanical properties are stable after the heat treatment. The method works well and provides good strength.

-    Simply put, we can rely on the production process and fly safe, explains Christer Persson, professor and head of Division for Engineering Materials.

Ceena Joseph recently defended her doctoral thesis “Microstructure Evolution and Mechanical Properties of Haynes 282”. She has a background in Metallurgical and Materials Science engineering.

-    One of my driving forces is the understanding of the behavior and the choice of materials within different applications and conditions. It’s always been interesting and made me pursue a career in material science, says Ceena Joseph.

Since her dissertation in March, Ceena Joseph has already started her new carrier, as a researcher within R&D for an aerospace manufacturing company.

Quick facts on Ceena Joseph
Living in: Sweden
Family: Husband & 2 kids
Interests: Travel, baking, reading
 
 
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Text and photo: Carina Schultz

Published: Fri 13 Apr 2018. Modified: Tue 17 Apr 2018