Investigation of the anisotropic cyclic damage behavior of selective laser melted AISI 316L stainless steel

Abstract

The additive manufacturing technique selective laser melting (SLM) is the most common process for metallic powders. The layer‐by‐layer process allows construction of components with high complex designs compared with conventional process routes. However, the orientation of parts related to the build platform and later to different loading conditions should be taken into account as the process‐induced microstructure and defects creating anisotropic mechanical behavior. To evaluate this influence of the building orientation as well as the process‐induced defects, different fatigue tests were performed on the SLM‐processed austenitic steel AISI 316 L (X2CrNiMo17‐12‐2). The distribution of the process‐induced porosity and, thus, the fatigue behavior is strongly related to the building direction, leading to a reduction of fatigue life for the tested 90° specimens of more than 90%.

Fatigue‐life prediction of additively manufactured material: Effects of heat treatment and build orientation

“…In addition to AM process parameters, design parameters—such as build orientation and scanning pattern—can also affect the thermal history . Consequently, AM parts can have more anisotropic behaviour than their wrought counterparts since the final mechanical performance of fabricated parts is directly related to the thermal history‐dependent microstructure …”

“…[10][11][12][13][14][15] Consequently, AM parts can have more anisotropic behaviour than their wrought counterparts since the final mechanical performance of fabricated parts is directly related to the thermal history-dependent microstructure. 2,[16][17][18] Historically, requirements of the parts' durability under cyclic loading (ie, fatigue) proved to be one of the most challenging ones to meet, particularly for new materials and manufacturing technologies such as AM. 5 The amount and distribution of anomalies and residual stresses as well as other microstructural features (eg, grain size and crystallographic texture)-as a consequence of non-uniform thermal history of each point during AM process-play a crucial role in fatigue behaviour.…”

On the fatigue crack growth behaviour of selective laser melting fabricated Inconel 625: Effects of build orientation and stress ratio

“…Selective laser melting (SLM) is one of the most promising additive manufacturing (AM) technologies with the convenience and feasibility of producing high temperature superalloy components, and this has received much attention in various fields, such as aerospace, automobile and biomedical industries. 1 Previous studies have been mainly carried out on the processing parameters, [2][3][4][5] microstructure characteristics of formed parts, [4][5][6][7] welding cracking 6 and effect of post-process, 7-9 such as heat treatment (HT) and hot isostatic pressing (HIP). In order to apply the SLM superalloy into the manufacturing of turbine blades and combustors with high reliability, 10,11 the fatigue behaviour of this kind of materials should be investigated.…”

Effects of scanning speed on creep behaviour of 316L stainless steel produced using selective laser melting

“…The influence of porosity and roughness on fatigue behaviour of SLM 316L stainless steel was experimentally examined at room temperature 18 . The effects of heat treatment and building orientation on fatigue properties of SLM 316L stainless steel were investigated at room temperature 19,20 . However, the mechanical properties and behaviours at high temperature cannot always be predicted from those at room temperature.…”