21 mai 2021

Web-séminaire #7-2 (29/01/2021) Zhimao Wang (ICD / LAMSI)

Le GdR Concord (COuplage méCanique Oxydation Diffusion) lance une série de web-séminaire au rythme mensuel. Le séminaire porte sur la thématique de l’interdiffusion et croissance d’oxyde sous chargement thermomécanique.

Animateurs: Benoit PANICAUD (ICD) et Vincent MAUREL (CdM)

Zhimao Wang (ICD / LAMSI), Optimization of thermomechanical parameters for a growing oxide on metal system (résumé et CV ci-dessous)

Exposé #2 : Zhimao Wang (ICD / LAMSI)
Optimization of thermomechanical parameters for a growing oxide on metal system

Chromium-based alloys have been developed to form chromia layers in oxidizing environments for high temperature applications, providing a good protection against further oxidation. The mechanical behavior and oxide layer growth of yttria-coated or zirconium-doped Ni28Cr alloy are presently studied under high temperature oxidation conditions. These kind of reactive elements can decrease oxidation kinetics and significantly increase the adhesion of chromia layer on the metallic substrate. However, during oxidation, a compressive stress generally occurs in thermally grown oxide (TGO) due to the oxide layer and its mechanical interaction with the metallic substrate. These growth stresses, combined with the thermal stresses that develop during temperature changes, may initiate and cause layer cracking or spallation, which limits the lifetime of alloys in such a challenging environment. For prediction of this lifetime, it is important to know with accuracy the thermomechanical behavior of such a system. Therefore, a thermomechanical modelling is proposed and applied to optimize numerically the unknown parameters, especially viscoplastic ones. For the raw material and modified materials by reactive elements, the creep parameter decreases with a lower temperature, which means that the viscoplastic strain decreases with a decreasing temperature. For the yttria-coated or zirconium-doped material, the main result is an increase of the activation energy of this creep parameter with the quantity of reactive element.


2017-Present : PhD candidate at University of Technology of Troyes in co-direction with University of La Rochelle
During my thesis, we mainly studied the oxidation phenomena of nickel-based alloy with and without reactive elements. In the experimental aspect, we used synchrotron XRD in reflection mode and transmission mode to determinate the stress in metal layer and in oxide layer. In the analysis and simulation aspects, we tried to optimize the thermomechanical parameters of this complex system and simulate the system by using the finite element method, for comparison to experimental results.

2014 – 2017 : Master at University of Technology of Troyes
Mechanical Numerical Simulation

2012 – 2016 : Northwestern Polytechnic University
Flight Vehicle Power Engineering