Simulations provide valuable knowledge about the metal microstructures

– Additive manufacturing obviously revolutionizes the industry, states Chamara. Engineers find opportunities that traditional production methods cannot provide.

But additive manufacturing also calls for ways to extend materials knowledge, not least in the case of Alloy 718, which is one of the most widely used alloys in the gas turbine industry.

– During additive manufacturing, the alloy is exposed to high temperatures, and they apply to both the additive process and the post heat treatment. Temperature and time are two crucial parameters for the final microstructure. And the microstructure, in turn, is crucial for the material’s mechanical properties.

– Being able to control the entire process of arriving at a final microstructure that provides the desired material properties, is a challenging task, Chamara states. However, there is no technology available today that can help us observe what actually happens to the Alloy 718 microstructure when temperature changes.

The only way to pursue such studies is real-life experiments. Test rods are exposed to varying temperature conditions during varying time sequences. What happens to the microstructures is studied afterwards. But this is a time and costly method, especially considering that temperatures and time sequences can vary a thousandfold.

Simulations with good precision

Chamara's research offers an alternative. Instead of real-life testing, he makes simulations using state-of-the-art computer-based models. There you can see how the microstructure changes depending on temperature and time.

– My computerized simulations come with high qualitative value and good precision, Chamara says. They can predict which paths to take, and which paths to avoid, in subsequent real-life experiments.

– In short, my research contributes to better designed and more goal-oriented experiments.

The research also provides better understanding and knowledge of the microstructures in the Alloy 718; why and how they are affected by various parameters during the additive manufacturing process and post heat treatment.

Saves time and money

Modelling of microstructures is a well-established technology. It has been used for more than 30 years in studies of cast components. In additive manufacturing, on the other hand, the method is new. In this field, Chamara Kumara's research is pioneering work.

Saving time and money for the industry is at the core of the research. Real-life experiments can arrive faster at the manufacturing parameters required for Alloy 718 to obtain the desired properties. This also paves the way for increased and more qualified use of additive manufacturing.

Chamara’s research has been part of University West's project ‘Sustainable manufacturing through next generation additive processes’ (Suman-Next).

“There are no hierarchies here”

For Chamara, modelling has been a passion ever since his Bachelor’s studies in Sri Lanka. During the time as a doctoral student, his dedication has grown even greater. He came to Sweden in 2012 on an internship and worked with thermal spraying. Later he took his Master's degree in manufacturing engineering at University West.

– I appreciate the Swedish working life culture. There are no hierarchies here. You will be respected, and it is no problem to talk to a professor.

– When I finish my doctorate, I plan to stay in the academia and further use my expertise and skills to carry out cutting edge research that adds value to the industry and academia. I also want to use my knowledge and skills to teach the next generation of engineers and researchers.

Link to Chamara Kumara's dissertation: ”Microstructure Modelling of Additive Manufacturing of Alloy 718”

Contact information: Email: chamara.kumara@hv.se. Phone: 0520-22 33 59.