“The Slug Test”: Inline Assessment of Yield Stress for Extrusion-Based Additive Manufacturing

2020 ◽  
pp. 216-224
Author(s):  
Nicolas Ducoulombier ◽  
Paul Carneau ◽  
Romain Mesnil ◽  
Léo Demont ◽  
Jean-François Caron ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Yield Stress ◽  
Slug Test

Reinforcing Inconel 718 Superalloy by Nano-TiC Particles in Selective Laser Melting

2015 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Yun Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Ultimate Tensile Strength ◽  
Yield Stress ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Reinforcement Particle ◽  
Manufacturing Processes ◽  
Laser Melting

Metal components produced by additive manufacturing processes usually have inferior properties and performances as compared with the counterparts by the traditional forming and machining processes. To close the gap, the metal matrix can be strengthened by adding reinforcement particles in additive manufacturing processes. This research presents the fabrication of nano-TiC reinforced Inconel 718 composites using selective laser melting (SLM). Tensile and wear performance tests are conducted to evaluate the mechanical properties of the formed composites. It is discovered that the composites exhibit improved mechanical properties in terms of ultimate tensile strength and yield stress. Compared with the pure Inconel 718 specimens by SLM, the ultimate tensile strength and yield stress of the reinforced Inconel 718 increase by 207 MPa and 204 MPa, respectively, with 0.5 wt.% addition of nano-TiC particle. Smaller increases are observed with 0.25 wt.% and 1.0 wt.% nano-TiC additions. On the other hand, the addition of nano-TiC particles decreases the ductility of Inconel 718. To investigate the strengthening mechanism of nano reinforcement particles in SLM, the microstructures with different levels of nano-TiC particles are observed. The results indicate that the microstructure of Inconel 718 is remarkably refined by the TiC particles, and the reinforcement particle significantly impede the growth of columnar grain in the solidification process.

scholarly journals Strain Rate Sensitivity of the Additive Manufacturing Material Scalmalloy®

2021 ◽  
Author(s):  
P. Jakkula ◽  
G. Ganzenmüller ◽  
F. Gutmann ◽  
A. Pfaff ◽  
J. Mermagen ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Strain Rate ◽  
Yield Stress ◽  
Strain Rate Sensitivity ◽  
Mass Density ◽  
Rate Sensitivity ◽  
Heat Treating ◽  
Tensile Tests ◽  
Strain Rates ◽  
Interesting Candidate

AbstractThis work investigates the influence of strain rate on the stress/strain behaviour of Scalmalloy. This material is an aluminium–scandium–magnesium alloy, specifically developed for additive manufacturing. The bulk yield stress of the material processed by Selective Laser Melting is approximately 340 MPa which can be increased by heat-treating to approximately 530 MPa. These numbers, combined with the low mass density of 2.7 g/cm3, make Scalmalloy an interesting candidate for lightweight crash-absorbing structures. As this application is inherently dynamic, it is of interest to study the loading rate sensitivity, which is difficult to predict: Al–Sc alloys exhibit classic strain rate sensitivity with an increased yield stress at elevated strain rates. However, Al–Mg alloys are known to show the contrary effect, they exhibit less strength as strain rate is increased. To answer the question how these effects combine, we study the dynamic behaviour at four different strain rates ranging from 10−3 to 1000 /s using servo-hydraulic and split-Hopkinson testing methods. The resulting data is analysed in terms of strain rate sensitivity of tensile strength and failure strain. A constitutive model based on a simplified Johnson–Cook approach is employed to simulate the tensile tests and provides good agreement with the experimental observations.

scholarly journals Print Velocity Effects on Strain-Rate Sensitivity of Acrylonitrile-Butadiene-Styrene Using Material Extrusion Additive Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 149
Author(s):  
Wilco M. H. Verbeeten ◽  
Rob J. Arnold-Bik ◽  
Miriam Lorenzo-Bañuelos
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Strain Rate ◽  
Yield Stress ◽  
Strain Rate Sensitivity ◽  
Molecular Orientation ◽  
Activation Volume ◽  
Rate Sensitivity ◽  
Acrylonitrile Butadiene Styrene ◽  
Butadiene Styrene

The strain-rate sensitivity of the yield stress for Acrylonitrile-Butadiene-Styrene (ABS) tensile samples processed via material extrusion additive manufacturing (ME-AM) was investigated. Such specimens show molecular orientation and interstitial voids that affect the mechanical properties. Apparent densities were measured to compensate for the interstitial voids. Three different printing speeds were used to generate ME-AM tensile test samples with different molecular orientation. Printing velocities influenced molecular orientation and stretch, as determined from thermal shrinkage measurements. Likewise, infill velocity affected the strain-rate dependence of the yield stress. The ABS material manifests thermorheollogically simple behavior that can correctly be described by an Eyring flow rule. The changing activation volume, as a result of a varying print velocity, scales linearly with the molecular orientation, as captured in an estimated processing-induced pre-strain. Therefore, it is suggested that ME-AM processed ABS shows a deformation-dependent activation volume. This paper can be seen as initial work that can help to improve quantitative predictive numerical tools for ME-AM, taking into account the effects that the processing step has on the mechanical properties.

scholarly journals Strain Rate Sensitivity of the Additive Manufacturing Material Scalmalloy®

2021 ◽  
Author(s):  
Puneeth Jakkula ◽  
Georg Ganzenmüller ◽  
Florian Gutmann ◽  
Aron Pfaff ◽  
Jörg Mermagen ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Strain Rate ◽  
Yield Stress ◽  
Strain Rate Sensitivity ◽  
Mass Density ◽  
Rate Sensitivity ◽  
Heat Treating ◽  
Tensile Tests ◽  
Strain Rates ◽  
Interesting Candidate

This work investigates the influence of strain rate on the stress/strain behaviour of Scalmalloy. This material is an aluminium-scandium-magnesium alloy, specifically developed for additive manufacturing. The bulk yield stress of the material processed by Selective Laser Melting is approximately 340 MPa which can be increased by heat-treating to approximately 530 MPa. These numbers, combined with the low mass density of 2.7 g/cm3, make Scalmalloy an interesting candidate for lightweight crash-absorbing structures. As this application is inherently dynamic, it is of interest to study the loading rate sensitivity, which is difficult to predict: Al-Sc alloys exhibit classic strain rate sensitivity with an increased yield stress at elevated strain rates. However, Al-Mg alloys are known to show the contrary effect, they exhibit less strength as strain rate is increased. To answer the question how these effects combine, we study the dynamic behaviour at four different strain rates ranging from 10−3 /s to 1000 /s using servo-hydraulic and Split-Hopkinson testing methods. The resulting data is analysed in terms of strain rate sensitivity of tensile strength and failure strain. A constitutive model based on a simplified Johnson-Cook approach is employed to simulate the tensile tests and provides good agreement with the experimental observations.

Regeneration von Knochendefekten mit computergesteuerter Herstellung von Gerüstträgern

2013 ◽  
Vol 22 (03) ◽  
pp. 180-187 ◽  
Author(s):  
J. Henke ◽  
J. T. Schantz ◽  
D. W. Hutmacher
Keyword(s):  
Tissue Engineering ◽  
Additive Manufacturing ◽  
Custom Made

ZusammenfassungDie Behandlung ausgedehnter Knochen-defekte nach Traumata oder durch Tumoren stellt nach wie vor eine signifikante Heraus-forderung im klinischen Alltag dar. Aufgrund der bestehenden Limitationen aktueller Therapiestandards haben Knochen-Tissue-Engineering (TE)-Verfahren zunehmend an Bedeutung gewonnen. Die Entwicklung von Additive-Manufacturing (AM)-Verfahren hat dabei eine grundlegende Innovation ausgelöst: Durch AM lassen sich dreidimensionale Gerüstträger in einem computergestützten Schichtfür-Schicht-Verfahren aus digitalen 3D-Vorlagen erstellen. Wurden mittels AM zunächst nur Modelle zur haptischen Darstellung knöcherner Pathologika und zur Planung von Operationen hergestellt, so ist es mit der Entwicklung nun möglich, detaillierte Scaffoldstrukturen zur Tissue-Engineering-Anwendung im Knochen zu fabrizieren. Die umfassende Kontrolle der internen Scaffoldstruktur und der äußeren Scaffoldmaße erlaubt eine Custom-made-Anwendung mit auf den individuellen Knochendefekt und die entsprechenden (mechanischen etc.) Anforderungen abgestimmten Konstrukten. Ein zukünftiges Feld ist das automatisierte ultrastrukturelle Design von TE-Konstrukten aus Scaffold-Biomaterialien in Kombination mit lebenden Zellen und biologisch aktiven Wachstumsfaktoren zur Nachbildung natürlicher (knöcherner) Organstrukturen.

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