Impact of laser powder bed fusion processing on the cyclic and fatigue properties of Ni20Cr alloy - Archive ouverte HAL Access content directly
Journal Articles Materials Science and Engineering: A Year : 2024

Impact of laser powder bed fusion processing on the cyclic and fatigue properties of Ni20Cr alloy

Abstract

Additive manufacturing is a new-age technology specialising in intricate fabrication in the manufacturing industry. However, extremely high cooling rate and far-from-equilibrium kinetics produce heterogeneous microstructure and induce high initial dislocation density, porosity, and residual stress. These unique microstructural features are known to severely impact cyclic and fatigue properties of alloys. In such a context, we investigated the cyclic and fatigue properties of a Ni-20 wt%. Cr alloy manufactured via laser powder bed fusion process (LPBF) and compared with its cast counterpart. The fatigue testing was carried out with three different strain amplitudes depicting Low, Medium and High Cycle Fatigue (LCF, MCF, HCF). LPBF samples exhibited higher fatigue resistance than that of cast samples, however experienced early failure in all the conditions. Despite strong planar glide, LPBF samples exhibited softening behaviour; the degree of softening is similar for LCF and MCF and less pronounced for HCF. The cast samples did not undergo any softening whatsoever indicating huge differences in cyclic strain mechanisms. Masing analysis was proposed to graphically analyse this softening behaviour. Further, the flow stress was categorized into backstress and effective stress for LPBF and cast samples. Majority of softening in LPBF samples for LCF and MCF occurred via backstress, whereas effective stress is associated to HCF. To investigate the origin of this softening for LPBF samples, microstructure characterisations were performed during the softening and at fracture. Post-fatigue microstructure indicates a clear modification of the dislocation structures from those inherited from LPBF to those linked to fatigue. This gradual change in microstructure is expected to induce the cyclic softening.
Embargoed file
Embargoed file
0 3 6
Year Month Jours
Avant la publication
Tuesday, May 28, 2024
Embargoed file
Tuesday, May 28, 2024
Please log in to request access to the document

Dates and versions

hal-04311149 , version 1 (28-11-2023)

Identifiers

Cite

Shubham Sanjay Joshi, Williams Lefebvre, Yan Duval, Cendrine Folton, Eric Hug, et al.. Impact of laser powder bed fusion processing on the cyclic and fatigue properties of Ni20Cr alloy. Materials Science and Engineering: A, 2024, 890, pp.145915. ⟨10.1016/j.msea.2023.145915⟩. ⟨hal-04311149⟩
27 View
0 Download

Altmetric

Share

Gmail Facebook X LinkedIn More