Influence of porosity on mechanical and corrosion properties of SLM 316L stainless steel

Yang, Dengcui; Kan, Xinfeng; Gao, Pengfei; Zhao, Yue; Yin, Yuchen; Zhao, Zhengzhi; Sun, Jiquan

doi:10.1007/s00339-021-05191-4

Cited by 23 publications

(6 citation statements)

References 28 publications

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“…Microstructures with finer boundaries tend to generate nobler materials [9]. In the case of the sintered paste samples, the material's nobility decreases with increasing porosity [10]. These findings were consistent with the results obtained from AEN analysis.…”

Section: B Electrochemical Analysis Of Sintered Samplessupporting

confidence: 88%

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Understanding Cu Sintering and Its Role on Corrosion Behaviour for High-Temperature Microelectronic Application

Kotadia,

Ahuir-Torres,

Bhogaraju

et al. 2024

IMAPSource Proceedings

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There has been a significant rise in interest from academic and industry communities on copper nano and micro-particles-based sinter pastes for harsh environment die attach. However, sintering these particles is a complex process which is affected by many parameters, such as (i) particles size, shape, and distribution, (ii) sintering temperature, pressure, environment, and (iii) organic compounds used for the paste formulation. In literature, various research groups demonstrated that sintered copper layer can achieve good electrical conductivity and high strength. In our previous research [1, 2], we explained that microscale etched flakes are also capable of shear strength >30Mpa while sintering with 10 MPa bonding pressure at 275°C for just 1 minute with negligible paste cost (in comparison to silver paste). However, very limited knowledge exists on literature about corrosion behaviour in sintered copper interconnects. This, from experience in the industry with silver sintering has proven to be critical to applications. For examples in high power LED headlamp applications, minor exposure to residual Sulphur emerging from vulcanized rubber seals has been observed to cause corrosion in silver sintered interconnects. Therefore, corrosion and its impact on performance and reliability must be considered, especially for safety critical applications. For this reason, we have studied the relationship between copper sintered samples and corresponding corrosion behaviours and compared again to pure copper (conventionally produced). The corrosion resistance of the samples in salt water was assessed via various electrochemical analysis techniques and correlated with sintered microstructure. Sample produced better corrosion resistance when fabricated with higher density (less porosity). However, in case of the microscale copper flakes-based interconnects, a pitting behaviour was observed. The sintered copper paste samples showed to be nobler than commercial copper. In addition, copper oxide and its role in accelerating/preventing oxidation is also studied.

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Section: B Electrochemical Analysis Of Sintered Samplessupporting

confidence: 88%

“…The defects and imperfections are zones with dissimilar surface energy to matrix. This can produce activation or inactivation zones, increasing or reducing the potential of the sample [9,10]. The sintered copper paste 2 had less porosity and may have a finer microstructure than the sintered copper paste 1.…”

Section: B Electrochemical Analysis Of Sintered Samplesmentioning

confidence: 99%

Understanding Cu Sintering and Its Role on Corrosion Behaviour for High-Temperature Microelectronic Application

Kotadia,

Ahuir-Torres,

Bhogaraju

et al. 2024

IMAPSource Proceedings

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“…Interestingly, the porosity decreased with a scan speed of 1000 mm/s and increasing laser power (150-270 W). Conversely, Yang et al 38 reported negligible impacts of porosity on the 316L SS tensile strength, although the strain varied with pore size and quantity. Their study highlighted a lower laser power (135 W) as advantageous for higher deformation and less porosity.…”

Section: Feedstock and Roughnessmentioning

confidence: 96%

Build Plate Roughness Study on Part Bonding for the Laser Powder Bed Fusion Process

Ruiz-Huerta,

Correa-Gómez,

Castro-Espinosa

et al. 2024

JOM

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Additive manufacturing (AM) processes have emerged as valuable partners in conventional manufacturing, facilitating the production of low-batch components with complex geometries across diverse industries. However, despite ongoing advancements in various AM technologies, consistently achieving reliable and defect-free components remains a challenge. In powder metal AM, the use of substrates or build plates to support the entire build plays a crucial role in ensuring build stability. Build plate preparation typically involves surface grinding followed by finishing sanding, leading to variations in surface roughness between different manufacturing runs. This study aimed to elucidate the bonding characteristics at the build plate-part interface by investigating the porosity and build plate-part strength at different substrate surface roughness. To this end, a multi-roughness build plate was designed and fabricated for tensile testing via laser powder bed fusion (LPBF) processing of upright specimens. The specimens were subjected to computed tomography (CT) scans for porosity assessment, followed by tensile tests to evaluate the mechanical performance at the build plate-part interface (bp-p). CT inspection revealed no porosity at the interface for any roughness level. Furthermore, analysis of the tensile behavior in relation to substrate roughness (Ra values of 0.8 μm, 1.4 μm, 3.5 μm, and 4.4 μm) did not reveal statistically significant differences.

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“…[51] Another scenario is described in the case of the presence of these structures on the boundary of grains as the consequence of rapid cooling, causing the formation of segregates on the mentioned boundary in the form of cellular structure [52]. It was found that the conversion between cellular and reoriented (columnar) structures occurs naturally in the form of morphology variation, as on the melt pool interfaces in the case of grain boundaries [53]. Specimens made by additive manufacturing included commonly occurring discontinuities related to the SLM technology.…”

Section: Microstructure Evaluationmentioning

confidence: 99%

Stress Relieving Heat Treatment of 316L Stainless Steel Made by Additive Manufacturing Process

Gel’atko,

Hatala,

Botko

et al. 2023

Materials

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Residual stress occurs in the materials after different methods of processing due to the application of pressure and/or thermal gradient. The occurrence of residual stresses can be observed in both subtractive and additive-manufactured (AM) materials and objects. However, pressure residual stresses are considered, in some cases, to have a positive effect; there are applications where the neutral stress state is required. As there is a lack of standards describing the heat treatment of AM materials, there is a need for experimental research in this field. The objective of this article is to determine the heat treatment thermal regime to achieve close to zero stress state in the subsurface layer of additively manufactured AM316L stainless steel. The presented objective leads to the long-term goal of neutral etalons for eddy current residual stress testing preparation. A semi-product intended for the experiment was prepared using the Selective Laser Melting (SLM) process and subsequently cut, using Abrasive Water Jet (AWJ) technology, into experimental specimens, which were consequently heat-treated in combination with four temperatures and three holding times. Residual stresses were measured using X-ray diffraction (XRD), and microstructure variations were observed and examined. A combination of higher temperature and longer duration of heat treatment caused more significant stress relaxation, and the original stress state of the material influenced a degree of this relaxation. The microstructure formed of cellular grains changed slightly in the form of grain growth with randomly occurring unmolten powder particles, porosity, and inclusion precipitation.

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Influence of porosity on mechanical and corrosion properties of SLM 316L stainless steel

Cited by 23 publications

References 28 publications

Understanding Cu Sintering and Its Role on Corrosion Behaviour for High-Temperature Microelectronic Application

Understanding Cu Sintering and Its Role on Corrosion Behaviour for High-Temperature Microelectronic Application

Build Plate Roughness Study on Part Bonding for the Laser Powder Bed Fusion Process

Stress Relieving Heat Treatment of 316L Stainless Steel Made by Additive Manufacturing Process

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