Dynamic recrystallization's role in strength-ductility trade-off in polycrystalline Fe-Cr-Ni stainless steels produced by laser powder bed fusion

In this paper, the capability of laser powder bed fusion (L-PBF) systems to process stainless steel alloys is reviewed. Several classes of stainless steels are analyzed (i.e., austenitic, martensitic, precipitation hardening and duplex), showing the possibility of satisfactorily processing this class of materials and suggesting an enlargement of the list of alloys that can be manufactured, targeting different applications. In particular, it is reported that stainless steel alloys can be satisfactorily processed, and their mechanical performances allow them to be put into service. Porosities inside manufactured components are extremely low, and are comparable to conventionally processed materials. Mechanical performances are even higher than standard requirements. Micro surface roughness typical of the as-built material can act as a crack initiator, reducing the strength in both quasi-static and dynamic conditions.

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Laser Powder Bed Fusion of Precipitation-Hardened Martensitic Stainless Steels: A Review

Metals ◽

10.3390/met10020255 ◽

2020 ◽

Vol 10 (2) ◽

pp. 255 ◽

Cited By ~ 7

Author(s):

Le Zai ◽

Chaoqun Zhang ◽

Yiqiang Wang ◽

Wei Guo ◽

Daniel Wellmann ◽

...

Keyword(s):

Process Parameters ◽

Stainless Steels ◽

Austenitic Stainless Steels ◽

High Strength ◽

Machining Process ◽

Future Research ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Martensitic Stainless Steels

Martensitic stainless steels are widely used in industries due to their high strength and good corrosion resistance performance. Precipitation-hardened (PH) martensitic stainless steels feature very high strength compared with other stainless steels, around 3-4 times the strength of austenitic stainless steels such as 304 and 316. However, the poor workability due to the high strength and hardness induced by precipitation hardening limits the extensive utilization of PH stainless steels as structural components of complex shapes. Laser powder bed fusion (L-PBF) is an attractive additive manufacturing technology, which not only exhibits the advantages of producing complex and precise parts with a short lead time, but also avoids or reduces the subsequent machining process. In this review, the microstructures of martensitic stainless steels in the as-built state, as well as the effects of process parameters, building atmosphere, and heat treatments on the microstructures, are reviewed. Then, the characteristics of defects in the as-built state and the causes are specifically analyzed. Afterward, the effect of process parameters and heat treatment conditions on mechanical properties are summarized and reviewed. Finally, the remaining issues and suggestions on future research on L-PBF of martensitic precipitation-hardened stainless steels are put forward.

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AUSTENITIC STAINLESS STEELS MANUFACTURING BY LASER POWDER BED FUSION TECHNIQUE

Acta Metallurgica Slovaca ◽

10.36547/ams.26.1.329 ◽

2020 ◽

Vol 26 (1) ◽

pp. 24-26

Author(s):

Andrea Di Schino ◽

Paolo Fogarait ◽

Domenico Corapi ◽

Orlando Di Pietro ◽

Chiara Zitelli

Keyword(s):

Surface Roughness ◽

Mechanical Behaviour ◽

Stainless Steels ◽

Austenitic Stainless Steels ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Fusion Technique ◽

Powder Bed ◽

Dynamic Conditions ◽

Mechanical Performances

In this paper we report about the possibility to process stainless steels by laser powder bed fusion (L-PBF) systems. Austenitic stainless steels are analysed showing the possibility to successfully process them, targeting different applications. In particular, it is shown that stainless steels can be successfully processed and their mechanical behaviour allow them to be put in service. Porosities inside manufactured components are extremely low and comparable to conventionally processed materials. Mechanical performances are even higher than standard requirements. Micro surface roughness typical of the as-built material can act as crack initiator, reducing the strength in both quasi-static and dynamic conditions.

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Deformation-induced martensitic transformation in 316L stainless steels fabricated by laser powder bed fusion

Materials Letters ◽

10.1016/j.matlet.2021.130377 ◽

2021 ◽

pp. 130377

Author(s):

Xiaoqing Ni ◽

Decheng Kong ◽

Wenheng Wu ◽

Liang Zhang ◽

Chaofang Dong

Keyword(s):

Martensitic Transformation ◽

Stainless Steels ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed

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Near-Threshold Fatigue Crack Growth Rates of Laser Powder Bed Fusion Produced Ti-6Al-4V

SSRN Electronic Journal ◽

10.2139/ssrn.3622627 ◽

2020 ◽

Author(s):

Thorsten Hermann Becker ◽

Nur Mohamed Dhansay ◽

Gerrit Matthys Ter Haar ◽

Kim Vanmeensel

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Growth Rates ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Crack Growth Rates ◽

Near Threshold

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Machine-Learning Assisted Laser Powder Bed Fusion Process Optimization for AlSi10mg: New Microstructure Description Indices and Fracture Mechanisms

SSRN Electronic Journal ◽

10.2139/ssrn.3681162 ◽

2020 ◽

Author(s):

Qian Liu ◽

Hongkun Wu ◽

Moses J. Paul ◽

Peidong He ◽

Zhongxiao Peng ◽

...

Keyword(s):

Machine Learning ◽

Process Optimization ◽

Fusion Process ◽

Fracture Mechanisms ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed

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On the Relevance of Volumetric Energy Density in the Investigation of Inconel 718 Laser Powder Bed Fusion

Materials ◽

10.3390/ma13030538 ◽

2020 ◽

Vol 13 (3) ◽

pp. 538 ◽

Cited By ~ 6

Author(s):

Fabrizia Caiazzo ◽

Vittorio Alfieri ◽

Giuseppe Casalino

Keyword(s):

Surface Roughness ◽

Energy Density ◽

Process Parameters ◽

Vickers Hardness ◽

Powder Bed Fusion ◽

Processing Conditions ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Fractional Density ◽

Experimental Variation

Laser powder bed fusion (LPBF) can fabricate products with tailored mechanical and surface properties. In fact, surface texture, roughness, pore size, the resulting fractional density, and microhardness highly depend on the processing conditions, which are very difficult to deal with. Therefore, this paper aims at investigating the relevance of the volumetric energy density (VED) that is a concise index of some governing factors with a potential operational use. This paper proves the fact that the observed experimental variation in the surface roughness, number and size of pores, the fractional density, and Vickers hardness can be explained in terms of VED that can help the investigator in dealing with several process parameters at once.

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