Thermal cracking: clarifying the effects of phases, voids and grains through characterisation and crystal plasticity modelling
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Thermally-induced cracking typically occurs during the cooling stage of various manufacturing processes, and is commonly seen in multiphase or the joints of dissimilar materials due to mismatch in their thermo-mechanical properties, such as thermal expansion, elastic-plastic deformation and, in some cases, phase transformation. However, the underlying cracking mechanism associated with local microstructure is still elusive. To improve the mechanistic understanding of thermal cracking, this work uses the diffusion-bonded 9Cr-1Mo steel as an example to study the key microstructural variables, such as interfacial phases, voids, grain boundary migration and crystallographic orientations. Meanwhile, a temperature-dependent crystal plasticity model coupled with a cohesive zone model is developed to provide more insights into the thermal-induced stress distribution at the grain scale. It is found that the stress at the void-free boundary of martensite and ferrite is dominated by shear, and its magnitude is insufficient to nucleate cracks. Whereas voids at phase boundaries can induce significant tensile stress, resulting in cracking at the phase boundaries as well as diffusion-bonded interfaces. Also, the occurrence of interfacial grain boundary migration plays an important role in local stress distribution. These microstructure features and their evolution are experimentally observed and used to verify the developed crystal plasticity models. These findings enhance the understanding of the influence of microstructure features on thermal cracking and provide a guide to designing and fabricating the microstructure with improved thermal crack resistance in various manufacturing processes.
Date Issued
2024-05-01
Date Acceptance
2024-03-05
Citation
Journal of the Mechanics and Physics of Solids, 2024, 186
ISSN
0022-5096
Publisher
Elsevier
Journal / Book Title
Journal of the Mechanics and Physics of Solids
Volume
186
Copyright Statement
© 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.1016/j.jmps.2024.105600
Subjects
COHESIVE ZONE MODEL
Crystal plasticity
Diffusion bonding
FATIGUE
FINITE-ELEMENT SIMULATION
Grain boundary
Martensite
Materials Science
Materials Science, Multidisciplinary
Mechanics
NEUTRON-DIFFRACTION
NUMERICAL-SIMULATION
Physical Sciences
Physics
Physics, Condensed Matter
QUENCHING PROCESS
RESIDUAL-STRESSES
Science & Technology
STEEL PIPE
SUB-SIZE SPECIMENS
Technology
Thermal crack
TRANSFORMATION
Void
Publication Status
Published
Article Number
105600
Date Publish Online
2024-03-11