Digital Image Correlation Analysis for Functionally Graded Material SS316L/Inconel 625

Du, Weihang

Digital Image Correlation Analysis for Functionally Graded Material SS316L/Inconel 625

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Author:: Du, Weihang
Graduate Program:: Industrial Engineering
Degree:: Master of Science
Document Type:: Master Thesis
Date of Defense:: March 21, 2022
Committee Members:: Jingjing Li, Thesis Advisor/Co-Advisor
Hongtao Sun, Committee Member
Steven Landry, Program Head/Chair
Keywords:: DIC
FGM
SS316L/Inconel625
Abstract:: This research studies the mechanical properties of the metallic functionally graded material (FGM) with the hot isostatic pressing (HIP) treatment. This material was generated based on SS 316L alloy and Inconel 625 alloy powders by applying the laser metal deposition (LMD) process with the 5 intermediate gradient structures from 100%/0% SS 316L/Inconel 625 to the 0%/100% SS 316L/Inconel 625 components. The longitudinal and transverse deformation directions were employed to provide accurate details of the deformation governing mechanisms. Both experiments in two directions show 75%/25% SS 316L/Inconel 625 layer have the lowest mechanical properties is the location where the fracture happened. Therefore, two parts of the material characterization methods are used to analyze the mechanical properties of the fracture layer. Part a is the hardness test, and part b is the tensile test with the digital images correlation (DIC) technique were applied on different gradient structure layers of the FGM. Hardness test indicated that near Inconel 625 layers, 25%/75% SS 316L/Inconel 625 to 0%/100% SS 316L/Inconel 625 layers have larger hardness due to the finer grain size and Ni solid solution strengthening effects. DIC results in the tensile test technique provide the strain deformation in different gradient structure layers, which also presented 75%/25% SS 316L/Inconel 625 layer always causes plastic deformation with low strength in all gradient layers. The demonstration of this work is expected to inspire future studies about the metallic FGM’s mechanical properties on manufacturing processes.

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