Strain Rate-Dependent Compressive Properties of Bulk Cylindrical 3D-Printed Samples from 316L Stainless Steel.

Michaela Neuhäuserová,Tomáš Fíla,Ondřej Jiroušek,Jan Šleichrt,Anja Mauko,Jan Falta,Václav Rada,Petr Koudelka,Petr Zlámal

doi:10.3390/ma15030941

Abstract

The main aim of the study was to analyse the strain rate sensitivity of the compressive deformation response in bulk 3D-printed samples from 316L stainless steel according to the printing orientation. The laser powder bed fusion (LPBF) method of metal additive manufacturing was utilised for the production of the samples with three different printing orientations: 0, 45, and 90. The specimens were experimentally investigated during uni-axial quasi-static and dynamic loading. A split Hopkinson pressure bar (SHPB) apparatus was used for the dynamic experiments. The experiments were observed using a high-resolution (quasi-static loading) or a high-speed visible-light camera and a high-speed thermographic camera (dynamic loading) to allow for the quantitative and qualitative analysis of the deformation processes. Digital image correlation (DIC) software was used for the evaluation of displacement fields. To assess the deformation behaviour of the 3D-printed bulk samples and strain rate related properties, an analysis of the true stress–true strain diagrams from quasi-static and dynamic experiments as well as the thermograms captured during the dynamic loading was performed. The results revealed a strong strain rate effect on the mechanical response of the investigated material. Furthermore, a dependency of the strain-rate sensitivity on the printing orientation was identified.

Highlights

Three-dimensional printing/additive manufacturing (AM) has become a competitive production method for various kinds of materials and applications, first and foremost due to the principle of successively adding material based on a CAD model of the produced part [1]
The experimental investigations presented in this study revealed a significant strain rate sensitivity of the mechanical behaviour of 3D-printed 316L austenitic stainless steel
Based on comparison of the stress values evaluated from the quasi-static and low-rate dynamic experiments, the most prominent strain rate sensitivity was identified for specimens produced with the printing direction of 90◦

Summary

Introduction

Three-dimensional printing/additive manufacturing (AM) has become a competitive production method for various kinds of materials and applications, first and foremost due to the principle of successively adding material based on a CAD model of the produced part [1]. AM refers to several different techniques that, according to the International Organisation for Standardization (ISO), may be classified into seven categories: (a) binder jetting (BJ), (b) directed energy deposition (DED), (c) material extrusion (ME), (d) material jetting (MJ), (e) powder bed fusion (PBF), (f) sheet lamination (SL), and (g) vat photopolymerisation (VP) [1]. In the case of metals or composite materials containing metal particles, the PBF technique is the most commonly used method in metal AM processes, even though any of the listed technologies may be used. The basic principle of the PBF method is the layer-by-layer melting or sintering of a powdered metal using a high-power heat source such as laser or electron beam [3,4,5]

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