TY - JOUR

T1 - Fatigue crack initiation and propagation in plain and notched PBF-LB/M, WAAM, and wrought 316L stainless steel specimens

AU - Braun, Moritz

AU - Chen, Ting

AU - Shen, Junjun

AU - Fassmer, Henrik

AU - Klusemann, Benjamin

AU - Sheikhi, Shahram

AU - Ehlers, Sören

AU - Müller, Eckehard

AU - Sarmast, Ardeshir

AU - Schubnell, Jan

N1 - Publisher Copyright: © 2024 The Author(s)

PY - 2024/8

Y1 - 2024/8

N2 - Additively manufactured (AM) components—either made by laser-powder bed fusion or wire and arc additive manufacturing—typically contain process-related defects on and near surfaces that can be removed by machining. Various studies have shown that post-treatment, such as machining significantly improves the fatigue strength of AM parts. To this day, however, hardly any studies have investigated the fatigue strength of post-treated additively manufactured components with notches. In this study, fatigue tests were performed on plain and notched specimens to determine and compare the crack initiation and crack propagation behavior due to different manufacturing-related effects. Tests were performed on specimens produced by the two aforementioned AM processes and compared to specimens taken from wrought sheets. The fatigue strength of AM materials is influenced by microstructure, defects, residual stress, and notches. PBF-LB/M specimens exhibit the highest fatigue strength in plain, notch-free conditions, attributed to differences in microstructure and static strength affecting fatigue crack initiation. Notched specimens show larger differences among materials, with PBF-LB/M having shorter fatigue crack propagation life related to line-type defect clusters, while the plain PBF-LB/M specimens are less affected as their fatigue strength is primarily determined by fatigue crack initiation.

AB - Additively manufactured (AM) components—either made by laser-powder bed fusion or wire and arc additive manufacturing—typically contain process-related defects on and near surfaces that can be removed by machining. Various studies have shown that post-treatment, such as machining significantly improves the fatigue strength of AM parts. To this day, however, hardly any studies have investigated the fatigue strength of post-treated additively manufactured components with notches. In this study, fatigue tests were performed on plain and notched specimens to determine and compare the crack initiation and crack propagation behavior due to different manufacturing-related effects. Tests were performed on specimens produced by the two aforementioned AM processes and compared to specimens taken from wrought sheets. The fatigue strength of AM materials is influenced by microstructure, defects, residual stress, and notches. PBF-LB/M specimens exhibit the highest fatigue strength in plain, notch-free conditions, attributed to differences in microstructure and static strength affecting fatigue crack initiation. Notched specimens show larger differences among materials, with PBF-LB/M having shorter fatigue crack propagation life related to line-type defect clusters, while the plain PBF-LB/M specimens are less affected as their fatigue strength is primarily determined by fatigue crack initiation.

KW - Fatigue strength assessment

KW - Hybrid additive manufacturing

KW - Microstructural defects

KW - Post-production treatment

KW - Selective laser melting

KW - Wire arc additive manufacturing

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85197744098&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2024.113122

DO - 10.1016/j.matdes.2024.113122

M3 - Journal articles

AN - SCOPUS:85197744098

VL - 244

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

M1 - 113122

ER -