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Mechanical integrity evaluation of an additively manufactured Ni-base superalloy
A modified CM247LC superalloy has recently been developed at Empa for additive manufacturing. The objective of this student project is to investigate the high-temperature mechanical integrity (tensile, fatigue, creep) of the developed alloy over a temperature range of 25-1000°C.
The additive manufacturing (AM) of the γ` precipitation strengthened Ni-base superalloys still remains a challenge due to their susceptibility to micro-cracking. A recent study at Empa identified the micro-crack mechanisms and demonstrate how process and alloy modifications can reduce the micro-cracking. Based on experimental evidence, reduction in the solidification interval of CM247LC was identified as a candidate for micro-crack mitigation and a new alloy was accordingly developed. Hf is found to have a significant influence on the freezing range of the alloy and a new CM247LC without Hf was produced. Samples fabricated with the Hf-free CM247LC, CM247LC NHf, in combination with optimized processing conditions exhibit a reduction in crack density of 98 %. As a next step, the high-temperature mechanical integrity evaluation of the alloy is planned.
Tensile, fatigue and creep test at various temperatures (25-1000°C) for the modified alloy will be performed within the proposed student project. Microstructural examinations (optical and electron microscopy) will be also conducted in parallel for interpretation of the outcomes of the mechanical experiments.
Task description
To start, the student shall familiarize him/herself with concepts related to microstructural features of the AM CM247 alloy and their correlation with the alloy's mechanical behaviour. The other components of the project include mechanical testing, data analysis, pre- and post-test microstructure characterization.
Division of work:
15% Theoretical Background, 50% Experiments / Validation, 25% Data Analysis, 10% Documentation
This project is suitable for **ETH** students.
The additive manufacturing (AM) of the γ` precipitation strengthened Ni-base superalloys still remains a challenge due to their susceptibility to micro-cracking. A recent study at Empa identified the micro-crack mechanisms and demonstrate how process and alloy modifications can reduce the micro-cracking. Based on experimental evidence, reduction in the solidification interval of CM247LC was identified as a candidate for micro-crack mitigation and a new alloy was accordingly developed. Hf is found to have a significant influence on the freezing range of the alloy and a new CM247LC without Hf was produced. Samples fabricated with the Hf-free CM247LC, CM247LC NHf, in combination with optimized processing conditions exhibit a reduction in crack density of 98 %. As a next step, the high-temperature mechanical integrity evaluation of the alloy is planned.
Tensile, fatigue and creep test at various temperatures (25-1000°C) for the modified alloy will be performed within the proposed student project. Microstructural examinations (optical and electron microscopy) will be also conducted in parallel for interpretation of the outcomes of the mechanical experiments.
Task description To start, the student shall familiarize him/herself with concepts related to microstructural features of the AM CM247 alloy and their correlation with the alloy's mechanical behaviour. The other components of the project include mechanical testing, data analysis, pre- and post-test microstructure characterization.
Division of work: 15% Theoretical Background, 50% Experiments / Validation, 25% Data Analysis, 10% Documentation
This project is suitable for **ETH** students.
The objective of this student project is to investigate the high-temperature mechanical integrity (tensile, fatigue, creep) response of the developed CM247 NHf alloy in comparison with its previous versions.
The objective of this student project is to investigate the high-temperature mechanical integrity (tensile, fatigue, creep) response of the developed CM247 NHf alloy in comparison with its previous versions.
Leinenbach.pdf
