On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

Abstract

Additive manufacturing (AM) processes such as electron beam melting (EBM) are characterized by unprecedented design freedom. Topology optimization and design of the microstructure of metallic materials are enabled by rapid progress in this field. The latter is of highest importance as many applications demand appropriate mechanical as well as functional material properties. For instance, biodegradable implants have to meet mechanical properties of human bone and at the same time guarantee adequate cytocompatibility and degradation rate. In this field, pure iron has come into focus in recent studies due to its low toxicity. Hierarchical microstructures resulting from the EBM solidification processes and intrinsic heat treatment, respectively, allow for an adjustment of the degradation behavior and may promote enhanced fatigue strength. Herein, commercially pure iron (cp‐Fe) is processed by EBM. Microstructural analysis as well as an evaluation of the cyclic mechanical material properties are conducted. The results are compared to a hot‐rolled (HR) reference material. A contradiction observed as the EBM‐processed cp‐Fe (EBM Fe) shows lower ultimate tensile strength under monotonic loading but improved fatigue properties compared to the HR Fe. It is revealed that such a unique behavior originates from prevailing microstructural features in the EBM as‐built condition.

Influence of hydrogel coatings on corrosion and fatigue of iron in simulated body fluid

“…The results for the fatigue tests without corrosive influence on pure Fe are taken from comparable investigations by Bruder. [ 32 ] In addition, reference tests were carried out as part of this study; the results for mechanical fatigue testing of the pure Fe have already been shown partly in Torrent et al [ 33 ]…”

“…The same test set‐up was used in Torrent et al for the mechanical fatigue testing of pure iron manufactured by electron beam melting. [ 33 ]…”

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

“…Electrolyte iron has impurities lower than 600 ppm and requires controlled environment melting and multistage purification processes [ 9 ]. Torrent et al performed electron beam melting to manufacture electrolytic pure iron having 99.99% purity [ 10 ]. Chikoshi et al used anion exchange and plasma arc melting to remove metallic impurities.…”

On the Impact of Build Envelope Sizes on E-PBF Processed Pure Iron

“…As a potential biodegradable implant material, commercially pure iron (cp-Fe) was processed via electron beam powder bed fusion (E-PBF) in a recent publication. [14] It was shown that an overall process temperature level below the phase transformation temperature (c M a) leads to a microstructure dominated by low-angle grain boundaries (LAGB). In the present work, identical process parameters were applied to manufacture the same type of specimens on the same E-PBF system; however, a different build envelope size was used.…”

“…Fig.4-Stress-strain curves for plate 100 and plate 50 processed E-PBF cp-Fe specimens (partly recompiled from Ref [14]. under the terms of CC BY-NC-ND license).…”