PhD Position Summary: Remanufacturing damaged molds is of major interest for reducing
production and maintenance costs, and its development can make our industries more
competitive. Today, most studies on repair using additive manufacturing focus on restoring
geometry. However, it is crucial to control the mechanical properties after repair, since
molds/tools may be subjected to severe, repeated cyclic loading. The proposed project aims to
develop a methodology to better understand the effect of DED-WLAM metal additive
manufacturing parameters on the resulting properties and wear resistance, in order to achieve
controlled and reliable repairs. In addition, multiphysics, multi-scale models developed in
LAMIH will be used to analyze the complex interactions between thermal, mechanical, and
metallurgical phenomena, with the goal of establishing a Process (manufacturing parameters)–
Properties (mechanical, metallurgical)–Structure (wear) relationship.
Description of PhD: Remanufacturing damaged molds and tooling by metal additive
manufacturing (AM) offers major advantages: (i) it is a more environmentally friendly solution
that preserves natural resources and supports sustainable development, and (ii) it can
significantly reduce maintenance costs for industry [CHE14]. Metal AM processes involve
complex couplings between multiple physical phenomena (thermal, metallurgical, mechanical,
fluid flow, etc.), which makes interpretation and control challenging.
Today, the main criterion used to assess repair quality is often limited to restoring geometry.
This is insufficient to meet the mechanical requirements for repaired molds, which
will be subjected to severe cyclic loading. Although studies have validated the feasibility of
restoring molds by AM, controlling mechanical properties after repair remains very difficult
and directly affects the service life of repaired molds. Many scientific barriers therefore
remain to be overcome in order to master mechanical properties and improve wear resistance
and durability. A major current challenge is to establish relationships between manufacturing
parameters, AM melt-pool characteristics, and the resulting mechanical properties (wear), in
connection with overall repair quality.
Many studies have investigated melt-pool characteristics (shape, temperature, stability) and
reported strong inhomogeneity, which can lead to heterogeneous mechanical properties and the
presence of defects such as porosity.
This PhD aims to control the mechanical and tribological performance of repaired zones
produced by DED-WLAM by combining experimental, characterization, and modeling
approaches:
- Experimental optimization of repair parameters, supported by in-situ monitoring
(e.g., high-speed and thermal imaging) to quantify melt-pool shape, temperature and
stability.
- Multi-scale mechanical characterization (nano, micro, and component scales)
coupled with
metallurgical analyses to connect process conditions to microstructure,
defects and local properties.
- Functional validation through wear testing of the repaired area on the TRIBOLAB
platform (LAMIH) to assess repair quality under representative tribological conditions
and relate local properties to lifetime.
- Application the numerical models developed in LAMIH to simulate the
Remanufacturing process to improve understanding, predict the effect of parameters on
performance, and guide optimization.
