Invited Speaker

Assoc. Prof. Yawei Peng

Nanjing Tech University

E-mail: pengyw@njtech.edu.cn

Title: Anisotropic response of residual stress in low-temperature gaseous carburized LPBF-316L steel: experimental and numerical analysis

Profile:

Engaged in long-term research on advanced manufacturing of process equipment, service behavior of metallic materials, and surface engineering, with research outcomes supporting the high reliability and extended service life of critical components in the chemical and energy industries. Currently serves as a committee member of the Surface Modification Group of the Surface Engineering Branch of the Chinese Mechanical Engineering Society, a youth editorial board member of Frontiers in Structural Integrity (China Structural Integrity Alliance), and a guest editor for the international journal Coatings. Has led multiple research projects including those funded by the National Natural Science Foundation of China, sub-projects of the National Key R&D Program, and major projects under the heavy-duty gas turbine initiative. Published over 30 papers in international journals such as Scripta Materialia, Materials Science and Engineering A, and International Journal of Fatigue. Maintains long-term academic collaboration with Prof. Marcel A.J. Somers at the Technical University of Denmark (DTU), and has supervised several students who received funding from the China Scholarship Council (CSC) for joint training abroad. His students have received awards such as Jiangsu Province Excellent Doctoral Dissertation and multiple first and second prizes at international conferences.

Abstract:

Low-temperature gaseous carburization (LTGC) is a surface modification technique that produces expanded austenite with enhanced hardness and compressive residual stress under a controlled atmosphere. It is particularly effective for improving the surface performance of complex geometries produced by additive manufacturing. However, 316L stainless steel fabricated via laser powder bed fusion (L-PBF) exhibits crystallographic texture and microstructural anisotropy due to rapid solidification, which may influence the LTGC response.  This study investigates the effect of inherent microstructural anisotropy on residual stress development in L-PBF 316L stainless steel subjected to LTGC. Experimental results revealed that anisotropic compressive residual stresses across different planes—top (perpendicular) and side (parallel) to the build direction—within the expanded austenite case. This anisotropy was further examined via nanoindentation and in-situ EBSD. Building upon these experimental findings, a finite element analysis (FEA) was performed. Through the synergy of experimental observations and numerical simulations, the mechanisms responsible for the anisotropic response of residual stress in expanded austenite are revealed.