<p>This study is
focused on the prediction of residual stresses and microstructure development of
steel and aluminum alloys during laser-based manufacturing processes by means
of multi-physics numerical modeling.</p>
<p>A finite
element model is developed to predict solid-state phase transformation,
material hardness, and residual stresses produced during laser-based
manufacturing processes such as laser hardening and laser additive
manufacturing processes based on the predicted temperature and geometry from a
free-surface tracking laser deposition model. The solid-state phase
transformational model considers heating, cooling, and multiple laser track heating
and cooling as well as multiple layer tempering effects. The residual stress
model is applied to the laser hardening of 4140 steel and to laser direct deposition
of H13 tool steel and includes the effects of thermal strain and solid-state
phase transformational strain based on the resultant phase distributions.
Predicted results, including material hardness and residual stresses, are
validated with measured values.</p>
<p>Two dendrite
growth predictive models are also developed to simulate microsegregation and
dendrite growth during laser-based manufacturing processes that involve melting
and solidification of multicomponent alloys such as laser welding and laser-based
additive manufacturing processes. The first model uses the Phase Field method
to predict dendrite growth and microsegregation in 2D and 3D. It is validated
against simple 2D and 3D cases of single dendrite growth as well as 2D and 3D
cases of multiple dendrite growth. It is then applied to laser welding of
aluminum alloy Al 6061 and used to predict microstructure within a small domain.
</p>
The second model uses a novel technique by
combining the Cellular Automata method and the Phase Field method to accurately
predict solidification on a larger scale with the intent of modeling dendrite
growth. The greater computational efficiency of the this model allows for the
simulation of entire weld pools in 2D. The model is validated against an
analytical model and results in the literature.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12465401 |
| Date | 16 June 2020 |
| Creators | Neil S. Bailey (5929484) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/NUMERICAL_MODELING_AND_EXPERIMENTAL_ANALYSIS_OF_RESIDUAL_STRESSES_AND_MICROSTRUCTURAL_DEVELOPMENT_DURING_LASER-BASED_MANUFACTURING_PROCESSES/12465401 |
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