Influence of processing parameters of selective laser melting on high‐cycle and very‐high‐cycle fatigue behaviour of Ti‐6Al‐4V

Abstract

Orthogonal experiment design together with the analysis of variance was used to examine the processing parameters (laser power, scan speed, layer thickness and hatch spacing) of selective laser melting (SLM) for superior properties of SLM parts, in which nine groups of specimens of Ti-6Al-4V were fabricated. The results clarify that the influence sequence of individual parameter on the porosity is laser power > hatch spacing > layer thickness > scan speed. Ultrasonic fatigue tests (20 kHz) were conducted for the SLMed specimens in highcycle fatigue (HCF) and very-high-cycle fatigue (VHCF) regimes. The S-N data show that the fatigue strength is greatly affected by the porosity: the group with the smallest porosity percentage having the highest fatigue strength in HCF and VHCF regimes. Then, the tests on the validation group were performed to verify the optimal combination of SLM processing parameters. Moreover, the observations by scanning electron microscopy revealed that fatigue cracks initiate at lack-of-fusion defects in the cases of surface and internal crack initiation.

Fatigue failures from defects in additive manufactured components: A statistical methodology for the analysis of the experimental results

“…For these reasons, the fatigue response of AM parts is typically worse than that of traditionally built parts, which are generally free of large defects with sizes comparable to those of AM parts. [9][10][11][12][13][14] The aim of the research is therefore to optimize the process parameters or the post-treatments in order to limit the formation of defects 15,16 or to define damage tolerance design approaches capable to ensure the structural integrity of AM parts, since the design procedure commonly adopted cannot be conservative and effective. 13 In order to properly compare the results of tests on AM parts and assess the influence of process parameters and post-treatments, the experimental data should be properly analyzed.…”

Prediction and evaluation of fatigue life via modified energy method considering surface processing

“…Since fatigue was proposed, scholars had studied it extensively (Dantas et al, 2019;Du et al, 2021;. Based on damage mechanics, the damage-coupled elastic-plastic constitutive model was established by He et al (2020), and the effect of loading sequence on the fatigue crack initiation of wind turbine gear was analyzed.…”

Development of an empirical process model for adjusted porosity in laser-based powder bed fusion of Ti-6Al-4V

“…Here, weight reduction without stiffness reduction would be of great interest. However, it is known, that pores are detrimental for the fatigue strength [57,58]. Regarding the limitations of this study it should be mentioned that all presented models are only valid within the examined parameter range, for the used machine set up and for the investigated geometries.…”