Cracking during thermal post-processing of laser powder bed fabricated CM247LC Ni-superalloy

John H. Boswell; Daniel Clark; Wei Li; Moataz M. Attallah

doi:10.1016/j.matdes.2019.107793

Cracking during thermal post-processing of laser powder bed fabricated CM247LC Ni-superalloy

John H. Boswell, Daniel Clark, Wei Li, Moataz M. Attallah^*

^*Corresponding author for this work

Metallurgy and Materials

Research output: Contribution to journal › Article › peer-review

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Abstract

The causes of cracking during thermal post-processing of laser powder bed fabricated (LPBF) CM247LC Ni-superalloy have been examined. Micro-hardness measurements and microstructural analyses were undertaken following short aging heat treatments around the phase transformation temperatures identified by Differential Scanning Calorimetry (DSC) analysis of the as-built condition. Results showed a steep increase in cracking density in the samples between 450 °C and 600 °C, which corresponded to changes in the microstructure, hardness, and elastic modulus. A combination of ductility dip cracking and strain age cracking mechanisms were identified as the primary causes of cracking in LPBF CM247LC following post-build thermal treatments. The results of this work shed light on the relationship between the heat treatment temperatures and the onset of post-build cracking, and could help develop post-LPBF heat treatments for high γ′ Ni-superalloys.

Original language	English
Article number	107793
Journal	Materials and Design
Volume	174
Early online date	10 Apr 2019
DOIs	https://doi.org/10.1016/j.matdes.2019.107793
Publication status	Published - 15 Jul 2019

Keywords

Laser powder bed fusion
Mechanical properties
Microstructure
Nickel superalloys

ASJC Scopus subject areas

Materials Science(all)
Mechanics of Materials
Mechanical Engineering

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Cite this

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title = "Cracking during thermal post-processing of laser powder bed fabricated CM247LC Ni-superalloy",

abstract = "The causes of cracking during thermal post-processing of laser powder bed fabricated (LPBF) CM247LC Ni-superalloy have been examined. Micro-hardness measurements and microstructural analyses were undertaken following short aging heat treatments around the phase transformation temperatures identified by Differential Scanning Calorimetry (DSC) analysis of the as-built condition. Results showed a steep increase in cracking density in the samples between 450 °C and 600 °C, which corresponded to changes in the microstructure, hardness, and elastic modulus. A combination of ductility dip cracking and strain age cracking mechanisms were identified as the primary causes of cracking in LPBF CM247LC following post-build thermal treatments. The results of this work shed light on the relationship between the heat treatment temperatures and the onset of post-build cracking, and could help develop post-LPBF heat treatments for high γ′ Ni-superalloys.",

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journal = "Materials and Design",

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T1 - Cracking during thermal post-processing of laser powder bed fabricated CM247LC Ni-superalloy

AU - Boswell, John H.

AU - Clark, Daniel

AU - Li, Wei

AU - Attallah, Moataz M.

PY - 2019/7/15

Y1 - 2019/7/15

N2 - The causes of cracking during thermal post-processing of laser powder bed fabricated (LPBF) CM247LC Ni-superalloy have been examined. Micro-hardness measurements and microstructural analyses were undertaken following short aging heat treatments around the phase transformation temperatures identified by Differential Scanning Calorimetry (DSC) analysis of the as-built condition. Results showed a steep increase in cracking density in the samples between 450 °C and 600 °C, which corresponded to changes in the microstructure, hardness, and elastic modulus. A combination of ductility dip cracking and strain age cracking mechanisms were identified as the primary causes of cracking in LPBF CM247LC following post-build thermal treatments. The results of this work shed light on the relationship between the heat treatment temperatures and the onset of post-build cracking, and could help develop post-LPBF heat treatments for high γ′ Ni-superalloys.

AB - The causes of cracking during thermal post-processing of laser powder bed fabricated (LPBF) CM247LC Ni-superalloy have been examined. Micro-hardness measurements and microstructural analyses were undertaken following short aging heat treatments around the phase transformation temperatures identified by Differential Scanning Calorimetry (DSC) analysis of the as-built condition. Results showed a steep increase in cracking density in the samples between 450 °C and 600 °C, which corresponded to changes in the microstructure, hardness, and elastic modulus. A combination of ductility dip cracking and strain age cracking mechanisms were identified as the primary causes of cracking in LPBF CM247LC following post-build thermal treatments. The results of this work shed light on the relationship between the heat treatment temperatures and the onset of post-build cracking, and could help develop post-LPBF heat treatments for high γ′ Ni-superalloys.

KW - Laser powder bed fusion

KW - Mechanical properties

KW - Microstructure

KW - Nickel superalloys

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Cracking during thermal post-processing of laser powder bed fabricated CM247LC Ni-superalloy

Abstract

Keywords

ASJC Scopus subject areas

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