scholarly journals Fatigue Behavior of Hybrid Components Containing Maraging Steel Parts Produced by Laser Powder Bed Fusion

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 835
Author(s):  
Luís Santos ◽  
Joel de de Jesus ◽  
Luís Borrego ◽  
José A. M. Ferreira ◽  
Rui F. Fernandes ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Fatigue Failure ◽  
Fatigue Behavior ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Hybrid Parts ◽  
Aisi H13 ◽  
Steel Aisi ◽  
Loading Tests

This investigation concerns about of fatigue behavior under controlled loading and under strain control for hybrid specimens with parts produced with conventional processes in steel AISI H13 and the stainless steel AISI 420 and the rest part produced by laser powder bed fusion in AISI 18Ni300 steel. The controlled loading tests were performed in constant and variable amplitude. Fatigue failure of hybrid samples occurs mostly in laser-melted parts, initiated around the surface, in many cases with multi-nucleation and propagated predominantly between the deposited layers. Fatigue strength of hybrid parts, tested under displacement control is similar, but for specimens tested under load control the fatigue strength the fatigue strength of hybrid specimens is progressively lesser than laser powder bed fusion samples. Despite a tendency to obtain conservative predictions, Miner’s law predicts reasonably the fatigue lives under block loadings. The interface between materials presented an excellent joining and fatigue strength because the fatigue failure of hybrid samples occurred mostly in laser melted parts out of the interface.

scholarly journals Effect of Surface and Subsurface Defects on Fatigue Behavior of AlSi10Mg Alloy Processed by Laser Powder Bed Fusion (L-PBF)

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1063 ◽  
Author(s):  
Milad Hamidi Nasab ◽  
Alessandro Giussani ◽  
Dario Gastaldi ◽  
Valeria Tirelli ◽  
Maurizio Vedani
Keyword(s):  
Crack Nucleation ◽  
Fatigue Behavior ◽  
Fatigue Behaviour ◽  
Surface Finishing ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Finishing Processes ◽  
Effect Of Surface ◽  
Subsurface Defects

The fatigue behaviour of an AlSi10Mg alloy processed by laser powder bed fusion (L-PBF) and subjected to different surface finishing processes was investigated paying special attention to the residual defects on the surface and the dominant fatigue failure mechanisms. Roughness measurements and qualitative surface morphology analysis showed smooth surfaces in the case of vibro-finishing and machining followed by polishing. The fatigue performance did not reveal to be directly related to surface roughness, but residual intrusions left on the finished surfaces. Post-mortem analysis showed single- or multiple-crack nucleation from pores opened on the surface, un-melted powders, or spatters considered as typical L-PBF defects. A fatigue limit of 195 MPa for machined and polished samples was obtained by substantial removal of surface and subsurface defects.

Tensile and Fatigue Properties of Ti-6Al-4V Alloy Fabricated by Laser Powder-Bed Fusion Process

2020 ◽  
Author(s):  
M. Shafiqur Rahman ◽  
Uttam K. Chakravarty
Keyword(s):  
Fatigue Life ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Functional Materials ◽  
Fatigue Properties ◽  
Small Scale ◽  
Powder Bed Fusion ◽  
Cycle Fatigue ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

Abstract The tensile and fatigue properties of laser-powder-bed-fusion (L-PBF) processed Ti-6Al-4V specimens are investigated at different loading conditions. Two types of as-built and post-machined L-PBF processed dogbone specimens are considered for the study, one is an ASTME8M round specimen and the other one is a customized small-scale flat structure. The tensile and fatigue behavior of the specimens are investigated numerically using the finite element (FE) method. The FE modeling considers both low cycle fatigue (LCF) and high cycle fatigue (HCF) test conditions by applying cyclic loads in fully-reversed and stress ratio R = 0.1 conditions. The FE results for the von Mises stress, strain, total deformation, fatigue life, factor of safety, and fatigue limit of the Ti-6Al-4V specimens are obtained at room temperature (295 K). Results obtained from the model show that the fatigue life decreases as the load increases. It is also found that fatigue life does not vary with the change of the test frequency under a specific fatigue load. The comparison of mechanical properties of the L-PBF processed specimens with conventionally manufactured Ti-6Al-4V parts is also shown to understand the differences in the tensile and fatigue behavior. The validation of the FE model is performed by comparing the numerical results for the yield stress and fatigue limit with the experimental results found from the literature. The overall study contains a detailed analysis of the tensile and fatigue behavior of additively manufactured Ti-6Al-4V parts and provides a guide to investigating the similar properties for other functional materials used in the L-PBF process.

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