Tensile behavior of stainless steel 304L to Ni-20Cr functionally graded material: experimental characterization and computational simulations

TL;DR

This paper investigates the mechanical behavior of a functionally graded material transitioning from stainless steel 304L to Ni-20Cr, combining experimental tensile testing with computational simulations to understand phase effects and ductility variations.

Contribution

It provides new insights into the phase composition and mechanical response of SS304L/NiCr FGMs through combined experimental and finite element analysis methods.

Findings

Brittle response linked to eutectic phase formation in NiCr-rich regions.

Ductile behavior of SS304L is preserved in the FGM.

Eutectic phase reduces ductility in high NiCr regions.

Abstract

This study presents experimental and computational analyses of the phase composition and mechanical behavior of a functionally graded material (FGM) grading from 100 vol% 304L stainless steel (SS304L) to 100 vol% Ni-20Cr (NiCr) in 10 vol% increments. The mechanical behavior of the FGM was evaluated by extracting tensile specimens from SS304L-rich and NiCr-rich regions of the FGM, with the former behaving in a ductile manner and the latter being relatively brittle. The brittle response of the NiCr-rich sample was explained by the presence of the eutectic FCC+BCC phase in this sample, as identified by Scheil-Gulliver simulations along with experimental phase and composition analyses. The spatially varying yield and flow behavior of the FGM was determined through comparison of finite element analysis simulations with experimentally measured stress-strain curves and surface strain contours. The results highlight that the overall ductile behavior of SS304L and brittle behavior of NiCr are preserved in the SS304L/NiCr FGM but the formation of the brittle eutectic phase further reduced the ductility within the regions where it formed (90 vol% NiCr/10 vol% SS304L).