Cracking mechanism in a laser powder bed fused cold-work tool steel: The role of residual stresses, microstructure and local elemental concentrations

Platl, Jan; Bodner, Sabine C.; Hofer, Christina; Landefeld, Andreas; Leitner, Harald; Turk, Christoph; Nielsen, Marc‐André; Demir, Ali Gökhan; Previtali, Barbara; Kečkéš, Jozef; Schnitzer, Ronald

doi:10.1016/j.actamat.2021.117570

Cited by 39 publications

(14 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another positive impact is that austenite has higher carbon solubility and reduces the precipitation of grain boundary carbides, which is beneficial to inhibit the stress‐induced cracking of eutectic carbide network. [ 17 ] We believe that this fully austenitic microstructure is conducive to the reduction of crack density in SLMed high‐speed steel. Quenched sample consists of martensite and retained austenite.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[ 15 ] In addition, Saewe et al [ 16 ] found that the temperature gradients in the SLM process create grain growth in the build direction, resulting in columnar dendritic crystal, which can cause brittleness and promote crack formation. Recent results produced by Platl et al [ 17 ] suggest the cracks propagate predominantly along the network of M 2 C eutectic carbide deposited at the grain boundaries of carbon martensite and retained austenite matrix. They indicated that the stress‐induced cracking of eutectic carbides, which emerge from the tensile stress accumulations during solidification and cooling stages, is the predominant cracking mechanism of the LPBF‐processed tool steel.…”

Section: Introductionmentioning

confidence: 99%

“…It is hypothesized that the nitrogen atmosphere could participate in laser melting process and lead to a predominantly or fully austenitic microstructure, reducing residual stresses, brittle martensite structure, and martensitic transformation stress, but without some drawbacks related to the increased carbon content mentioned earlier. [17,27] How to judge the existence and impact of nitrogen in steel is crucial. According to relevant studies by Abbasi et al, [33] V(C,N) and V-carbide widely exist in ferritic steel rich in carbon and nitrogen in the form of precipitation.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N₂ Atmosphere

Zhang

Sun

Gao

et al. 2023

steel research int.

View full text Add to dashboard Cite

The selective laser melting (SLM), also termed as laser powder bed fusion (LPBF), is attractive for its ability to fabricate complex metallic components with great geometrical design freedom and manufacturing capacity. [1,2] The high heating/cooling rate and thermal input of laser processing result in refined grain and tailored microstructure, [3] leading to a notable Hall-Petch effect and improved mechanical performance of manufactured parts. Furthermore, SLM provides an effective way for the design and fabrication of high performance metal matrix composites (MMCs), wherein varieties of reinforced particles, [4,5] carbon nanotube, [6] and whiskers [7] can be added to metals, alloys, and even intermetallics through both ex situ and in situ approaches. [8] High speed steels (HSS) [9] are widely used in the production of cutting tools, drilling tools, extrusion molds, precision dies, and high temperature bearings due to their combination of high hardness (>60 HRC), strength (bending strength >2000 MPa), and wear resistance (high amount of carbides). In recent years, SLM of high speed steel, cold work die steel, hot work die steel, and similar tool and die steels has gained significant attention due to its ability to produce complicated parts and implementation of individually forming internal cooling channels. [10,11] This can significantly increase the cooling efficiency, application reliability, and service life of SLM-manufactured tools and molds. However, the available data in the literature [12,13] have shown that high speed steels are prone to cracking during the SLM cyclic remelting process with fast cooling rates due to their high carbon content (ranging from 0.8 to >3 wt%), [14] large amount of strong carbide forming elements, and thermal residual stress. The microstructure of SLM-processed high speed steel usually consists of martensite, retained austenite, carbides, and possibly eutectic structures. [15] In addition, Saewe et al. [16] found that the temperature gradients in the SLM process create grain growth in the build direction, resulting in columnar dendritic crystal, which can cause brittleness and promote crack formation. Recent results produced by Platl et al. [17] suggest the cracks propagate predominantly along the network of M 2 C eutectic carbide deposited at the grain boundaries of carbon martensite and retained austenite matrix. They indicated that the stress-induced cracking of eutectic carbides, which emerge from the tensile stress accumulations during solidification and cooling stages, is the predominant cracking mechanism of the LPBF-processed tool steel. Therefore, several studies focus on the additional preheating [18,19] during the SLM process to reduce the cumulative tensile stress and residual stresses. Among these studies,

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N₂ Atmosphere

Zhang

Sun

Gao

et al. 2023

steel research int.

View full text Add to dashboard Cite

show abstract

“…During melting material tries to expand but is restricted by the underlying material thereby inducing compressive stress. Whereas in the cooling process the material tries to contract which leads to the creation of tensile stress 26,27 . If the stresses in the component overcome the elastic limit, plastic deformation occurs which leads to distortions of the component.…”

Section: Titaniummentioning

confidence: 99%

Unique materials for additive manufacturing enabling new series application

Risch¹,

Schauer²,

Shah³

et al. 2023

Laser 3D Manufacturing X

View full text Add to dashboard Cite

In laser powder bed-based metal 3D printing, the high cooling rates in the process have advantages or disadvantages depending on the used material. For unique materials like amorphous metals the high cooling rate is a big advantage. However, the high cooling rates can also lead to very high stresses in other materials like titanium. Preheating the system to 500°C enables the processing of special titanium alloys such as Ti6242.Applying additive manufacturing to conventionally produced parts allow the combination of multiple materials. The feasibility of material combinations using this technique depends on individual material properties. With adapted process strategies, different materials can be combined.

show abstract

Thermodynamics‐Guided High‐Throughput Discovery of Eutectic High‐Entropy Alloys for Rapid Solidification

Han,

Sun,

Xia

et al. 2024

Advanced Science

View full text Add to dashboard Cite

Excellent castability, significantly refined microstructure, and good mechanical properties make eutectic high‐entropy alloys (EHEAs) a natural fit for rapid solidification processes, e.g., additive manufacturing. Previous investigations have focused on developing EHEAs through trial and error and mixing known binary eutectic materials. However, eutectic compositions obtained from near‐equilibrium conditions do not guarantee a fully eutectic microstructure under rapid solidifications. In this work, a thermodynamically guided high‐throughput framework is proposed to design EHEAs for rapid solidification. Empirical formulas derived from past experimental observations and thermodynamic computations are applied and considered phase growth kinetics under rapid solidification (skewed phase diagram). The designed alloy candidate, Co25.6Fe17.9Ni22.4Cr19.1Ta8.9Al6.1 (wt.%), contains nanostructured eutectic lamellar and shows a high Vickers hardness of 675 Hv. In addition to this specific composition, the alloy design toolbox enables the development of new EHEAs for rapid solidification without the limitation of previous knowledge.

show abstract

Cracking mechanism in a laser powder bed fused cold-work tool steel: The role of residual stresses, microstructure and local elemental concentrations

Cited by 39 publications

References 49 publications

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N₂ Atmosphere

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N₂ Atmosphere

Unique materials for additive manufacturing enabling new series application

Thermodynamics‐Guided High‐Throughput Discovery of Eutectic High‐Entropy Alloys for Rapid Solidification

Contact Info

Product

Resources

About

Cracking mechanism in a laser powder bed fused cold-work tool steel: The role of residual stresses, microstructure and local elemental concentrations

Cited by 39 publications

References 49 publications

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N2 Atmosphere

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N2 Atmosphere

Unique materials for additive manufacturing enabling new series application

Thermodynamics‐Guided High‐Throughput Discovery of Eutectic High‐Entropy Alloys for Rapid Solidification

Contact Info

Product

Resources

About

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N₂ Atmosphere

Processing Fundamentals and Performance Investigation of Selective Laser Melting of High‐Speed Steel in Reactive N₂ Atmosphere