An Efficient Test Method for the Quantification of Technology-Dependent Factors Affecting the Fatigue Behavior of Metallic Additive Manufacturing Components

Abstract

Powder bed fusion (PBF) is the most widely used additive manufacturing (AM) technology for producing high-performance metal parts. The fatigue characterization of PBF metals is a fundamental step toward technology acceptance for structural applications. Most published fatigue characterizations have adopted standard specimens with machined gage sections, although, to be competitive with conventional technologies, machining of PBF parts should be minimized. Therefore, the impact of the as-built surface quality on the fatigue performance of PBF parts is a major concern for part design and qualification. We describe a novel testing approach that adopts miniature specimens and plane cyclic bending for the fatigue characterization of as-built PBF metals and assess this approach for the case of a Ti6Al4V alloy against data obtained with standard specimen geometries and test methods. The role of factors such as stress versus build directionality, geometrical notches, and PBF technology on the high-cycle fatigue of Ti6Al4V is then quantified. The proposed method is cost-effective and has flexible applicability. Therefore, it is useful for basic fatigue research of PBF metals and for supporting the qualification of fatigue-critical PBF parts.

As‐built surface quality and fatigue resistance of Inconel 718 obtained by additive manufacturing

“…The study adopted a testing methodology based on the use of miniature (22‐mm‐long) specimens characterized by a prismatic shape and dimensions shown in Figure 1A 9 . Specimens were tested under plane cyclic bending loading with a load ratio of R = 0 so that crack initiation occurred at the center of the flat top surface in an unnotched configuration.…”

Fatigue Behavior of Metallic Components Obtained by Topology Optimization for Additive Manufacturing

“…SLM process allows a wide range of materials processing, such as titanium alloys (e.g.Ti-6Al-4V), stainless steel, nickel-based alloys (Inconel) and aluminium alloys [8] [9]. The fatigue characterization of AM materials has been received intensive research focus in the recent years [10][11][12][13]. Nevertheless, the research about the fatigue behaviour of real components has deserved little attention, most likely due to yet limited knowledge about AM material fatigue behaviour and the complex interaction between the manufacturing…”