scholarly journals Effect of Process Parameters and Build Orientation on Microstructure and Impact Energy of Electron Beam Powder Bed Fused Ti-6Al-4V

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5376
Author(s):  
Spencer Jeffs ◽  
Robert Lancaster ◽  
Gareth Davies ◽  
William Hole ◽  
Brenna Roberts ◽  
...  
Keyword(s):  
Electron Beam ◽  
Process Parameters ◽  
Impact Energy ◽  
Impact Testing ◽  
Processing Parameter ◽  
Microstructural Characteristics ◽  
Vertical Orientation ◽  
Powder Bed ◽  
Build Orientation ◽  
The Impact

To fully exploit the benefits of additive manufacturing (AM), an understanding of its processing, microstructural, and mechanical aspects, and their interdependent characteristics, is necessary. In certain instances, AM materials may be desired for applications where impact toughness is a key property, such as in gas turbine fan blades, where foreign or direct object damage may occur. In this research, the impact energy of a series of Ti-6Al-4V specimens produced via electron beam powder bed fusion (EBPBF) was established via Charpy impact testing. Specimens were produced with five different processing parameter sets, in both the vertical and horizontal build orientation, with microstructural characteristics of prior β grain area, prior β grain width, and α lath width determined in the build direction. The results reveal that horizontally oriented specimens have a lower impact energy compared to those built in the vertical orientation, due to the influence of epitaxial grain growth in the build direction. Relationships between process parameters, microstructural characteristics, and impact energy results were evaluated, with beam velocity displaying the strongest trend in terms of impact energy results, and normalised energy density exhibiting the most significant influence across all microstructural measurements.

scholarly journals Comparison of Phase Characteristics and Residual Stresses in Ti-6Al-4V Alloy Manufactured by Laser Powder Bed Fusion (L-PBF) and Electron Beam Powder Bed Fusion (EB-PBF) Techniques

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 796
Author(s):  
Aya Takase ◽  
Takuya Ishimoto ◽  
Naotaka Morita ◽  
Naoko Ikeo ◽  
Takayoshi Nakano
Keyword(s):  
Electron Beam ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Process Parameters ◽  
Phase Evolution ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Solidification Temperature ◽  
Powder Bed ◽  
Β Phase

Ti-6Al-4V alloy fabricated by laser powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) techniques have been studied for applications ranging from medicine to aviation. The fabrication technique is often selected based on the part size and fabrication speed, while less attention is paid to the differences in the physicochemical properties. Especially, the relationship between the evolution of α, α’, and β phases in as-grown parts and the fabrication techniques is unclear. This work systematically and quantitatively investigates how L-PBF and EB-PBF and their process parameters affect the phase evolution of Ti-6Al-4V and residual stresses in the final parts. This is the first report demonstrating the correlations among measured parameters, indicating the lattice strain reduces, and c/a increases, shifting from an α’ to α+β or α structure as the crystallite size of the α or α’ phase increases. The experimental results combined with heat-transfer simulation indicate the cooling rate near the β transus temperature dictates the resulting phase characteristics, whereas the residual stress depends on the cooling rate immediately below the solidification temperature. This study provides new insights into the previously unknown differences in the α, α’, and β phase evolution between L-PBF and EB-PBF and their process parameters.

scholarly journals Evaluation of Microstructure and Impact Toughness of Shielded Metal Arc Dissimilar Weldments of High Strength Low Alloy Steel and Austenitic Stainless Steel

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Misbahu A Hayatu ◽  
Emmanuel T Dauda ◽  
Ola Aponbiede ◽  
Kamilu A Bello ◽  
Umma Abdullahi
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Toughness ◽  
Impact Energy ◽  
High Strength ◽  
Impact Testing ◽  
Welding Parameters ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
The Impact

There is a growing interest for novel materials of dissimilar metals due to higher requirements needed for some critical engineering applications. In this research, different dissimilar weld joints of high strength low alloy (HSLA) and 316 austenitic stainless steel grades were successfully produced using shielded metal arc welding (SMAW) process with 316L-16 and E7018 electrodes. Five variations of welding currents were employed within the specified range of each electrode. Other welding parameters such as heat inputs, welding speeds, weld sizes, arc voltages and time of welding were also varied. Specimens for different weld joint samples were subjected to microstructural studies using optical and scanning electron microscopes. The impact toughness test was also conducted on the samples using Izod impact testing machine. The analysis of the weld microstructures indicated the presence of type A and AF solidification patterns of austenitic stainless steels. The results further showed that the weld joints consolidated with E7018 electrode presented comparatively superior impact energy to the weldments fabricated by 316L-16 electrode. The optimum impact energy of E7018-weld joints (51J) was attained at higher welding heat inputs while that of 316L-16-weld joints (35J) was achieved at lower welding heat inputs, which are necessary requirements for the two electrodes used in the experiment. Hence, the dissimilar weld joints investigated could meet requirement for engineering application in offshore and other critical environments.Keywords—Dissimilar metal weld, heat input, impact toughness, microstructures

Impact of Process Parameters on the Tensile Properties of DLP Additively Manufactured ELAST-BLK 10 UV-Curable Elastomer

2021 ◽  
Author(s):  
Asma Ul Hosna Meem ◽  
Kyle Rudolph ◽  
Allyson Cox ◽  
Austin Andwan ◽  
Timothy Osborn ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Ultimate Tensile Strength ◽  
Tensile Properties ◽  
Process Parameters ◽  
Uv Light ◽  
Uv Curable ◽  
Build Orientation ◽  
Static Tensile ◽  
The Impact

Abstract Digital light processing (DLP) is an emerging vatphotopolymerization-based 3D-printing technology where full layers of photosensitive resin are irradiated and cured with projected ultraviolet (UV) light to create a three-dimensional part layer-by-layer. Recent breakthroughs in polymer chemistry have led to a growing number of UV-curable elastomeric photoresins developed exclusively for vat photopolymerization additive manufacturing (AM). Coupled with the practical manufacturing advantages of DLP AM (e.g., industry-leading print speeds and sub-micron-level print resolution), these novel elastomeric photoresins are compelling candidates for emerging applications requiring extreme flexibility, stretchability, conformability, and mechanically-tunable stiffness (e.g., soft robotic actuators and stretchable electronics). To advance the role of DLP AM in these novel and promising technological spaces, a fundamental understanding of the impact of DLP manufacturing process parameters on mechanical properties is requisite. This paper highlights our recent efforts to explore the process-property relationship for ELAST-BLK 10, a new commercially-available UV-curable elastomer for DLP AM. A full factorial design of experiments is used to investigate the effect of build orientation and layer thickness on the quasi-static tensile properties (i.e., small-strain elastic modulus, ultimate tensile strength, and elongation at fracture) of ELAST-BLK 10. Statistical results, based on a general linear model via ANOVA methods, indicate that specimens with a flat build orientation exhibit the highest elastic modulus, ultimate tensile strength, and elongation at fracture, likely due to a larger surface area that enhances crosslink density during the curing process. Several popular hyperelastic constitutive models (e.g., Mooney-Rivlin, Yeoh, and Gent) are calibrated to our quasi-static tensile data to facilitate component-level predictive analyses (e.g., finite-element modeling) of soft robotic actuators and other emerging soft-matter applications.

scholarly journals On the Impact of Build Envelope Sizes on E-PBF Processed Pure Iron

2021 ◽  
Author(s):  
C. J. J. Torrent ◽  
P. Krooß ◽  
T. Niendorf
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Thermal History ◽  
Powder Bed Fusion ◽  
Parameter Setting ◽  
Powder Bed ◽  
History Of ◽  
Specific Temperature ◽  
The Impact

AbstractIn additive manufacturing, the thermal history of a part determines its final microstructural and mechanical properties. The factors leading to a specific temperature profile are diverse. For the integrity of a parameter setting established, periphery variations must also be considered. In the present study, iron was processed by electron beam powder bed fusion. Parts realized by two process runs featuring different build plate sizes were analyzed. It is shown that the process temperature differs significantly, eventually affecting the properties of the processed parts.

scholarly journals A Melt Pool Temperature Model in Laser Powder Bed Fabricated CM247LC Ni Superalloy to Rationalize Crack Formation and Microstructural Inhomogeneities

2021 ◽  
Author(s):  
Di Wang ◽  
Sheng Li ◽  
Guowei Deng ◽  
Yang Liu ◽  
Moataz M. Attallah
Keyword(s):  
Energy Density ◽  
Process Parameters ◽  
Crack Formation ◽  
Crack Density ◽  
Chemical Compositions ◽  
Temperature Model ◽  
Powder Bed ◽  
Melt Pool ◽  
Melt Pool Temperature ◽  
The Impact

AbstractThis study of the laser powder bed fusion (LPBF) of γ′-strengthened Ni superalloy CM247LC focuses on the development of a melt pool temperature model to predict crack density within the alloy. This study also analyzes spatter and elemental evaporation, which might cause defects and inhomogeneities, at different melt pool temperatures. The melt pool temperature model provides more accurate predictions than the widely used energy density model. Spatter particles were collected and characterized to study their sizes and chemical compositions, compared with the virgin powder, recycled powder, and as-built samples, to probe the impact of their entrapment into the melt pool. This study also investigated Al evaporation, revealing that its extent does not correlate with the laser energy density and is believed to be rather limited by comparing the chemistry of the virgin powder and the build. Last, the impact of LPBF process parameters on the formation of these inhomogeneities, and accordingly crack formation, was studied using finite element analysis by estimating the maximum melt pool temperature and correlating it with the formation of the microstructural inhomogeneities. The morphology of the various cracking modes was associated with the process parameters.

scholarly journals The Influence of Process Parameters and Build Orientation on the Creep Behaviour of a Laser Powder Bed Fused Ni-based Superalloy for Aerospace Applications

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1390 ◽  
Author(s):  
Hani Hilal ◽  
Robert Lancaster ◽  
Spencer Jeffs ◽  
John Boswell ◽  
David Stapleton ◽  
...  
Keyword(s):  
Process Parameters ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Creep Behaviour ◽  
Test Method ◽  
Influence Of Process Parameters ◽  
Powder Bed ◽  
Build Orientation ◽  
Aerospace Applications ◽  
Layer Manufacturing

Additive Layer Manufacturing (ALM) is an innovative net shape manufacturing technology that offers the ability to produce highly intricate components not possible through traditional wrought and cast procedures. Consequently, the aerospace industry is becoming ever more attentive in exploiting such technology for the fabrication of nickel-based superalloys in an attempt to drive further advancements within the holistic gas turbine. Given this, the requirement for the mechanical characterisation of such material is rising in parallel, with limitations in the availability of material processed restricting conventional mechanical testing; particularly with the abundance of process parameters to evaluate. As such, the Small Punch Creep (SPC) test method has been deemed an effective tool to rank the elevated temperature performance of alloys processed through ALM, credited to the small volumes of material utilised in each test and the ability to sample material from discrete locations. In this research, the SPC test will be used to assess the influence of a number of key process variables on the mechanical performance of Laser Powder Bed Fused (LPBF) Ni-based superalloy CM247LC. This will also include an investigation into the influence of build orientation and post-build treatment on creep performance, whilst considering the structural integrity of the different experimental builds.

3D printed geometrically tessellated sheets with origami-inspired patterns

2021 ◽  
pp. 0021955X2110618
Author(s):  
Anastasia L. Wickeler ◽  
Hani E. Naguib
Keyword(s):  
Impact Energy ◽  
Single Layer ◽  
Impact Testing ◽  
Impact Loads ◽  
Geometrical Complexity ◽  
Impact Forces ◽  
3D Printed ◽  
The Impact ◽  
Multiple Configurations ◽  
Absorb Impact Energy

This study demonstrates that the impact energy absorption capabilities of flexible sheets can be significantly enhanced by implementing tessellated designs into their structure. Configurations of three tessellated geometries were tested; they included a triangular-based, a rectangular-based, and a novel square-based pattern. Due to their geometrical complexity, multiple configurations of these tessellations were printed from a rubber-like material using an inkjet printer with two different thicknesses (2 and 4 mm), and their ability to absorb impact energy was compared to an unpatterned inkjet-printed sheet. In addition, the effect of multi-sheets stacking was also tested. Due to the tailored structure, the impact testing showed that the single-layer sheets were more effective at absorbing impact loads, and experience less deformation, than their two-layer counterparts. The 4 mm thick tessellated patterns were most effective at absorbing impact loads; all three thick patterns measured about 40% lower impact forces transferred to the base of the samples compared to the unpatterned counterparts.

Impact Performance of ZnAl27Cu2.5MgMn Alloy from Room Temperature to 250°C

2014 ◽  
Vol 915-916 ◽  
pp. 597-601
Author(s):  
Ming Long Kang ◽  
Wu Hu ◽  
Jian Min Zeng
Keyword(s):  
Impact Toughness ◽  
Impact Energy ◽  
Room Temperature ◽  
Impact Testing ◽  
Impact Behavior ◽  
Impact Performance ◽  
Temperature Impact ◽  
Spectrum Curve ◽  
The Impact ◽  
Pendulum Impact

The impact performance of ZnAl27Cu2.5MgMn alloy from room Temperature to 2500 °C has been investigated by pendulum impact testing. The surface morphology of impact fracture is observed by scan electron microscope (SEM). The results indicate that impact energy of the alloy decreases as the temperature increases when the temperatures are lower than 100°C. Between 100°C and 200°C, impact energy increases as the temperature increases. And when the temperature exceeds 250°C, impact energy decreases dramatically. Impact energy gets to the maximum at room temperature. Impact behavior of the alloy can be evaluated by the width of impact spectrum curve. The wider the peak of impact spectrum curve, the higher the impact toughness. Whereas impact toughness is worse if peak is narrow.

Experimental and numerical behaviors of GFRP laminates under low velocity impact

2020 ◽  
Vol 54 (21) ◽  
pp. 2999-3007
Author(s):  
Hüseyin E Yalkın ◽  
Ramazan Karakuzu ◽  
Tuba Alpyıldız
Keyword(s):  
Contact Force ◽  
Impact Energy ◽  
Damage Mechanics ◽  
Matrix Material ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Wide Range ◽  
The Impact

The aim of the study is to investigate the behavior of laminated composites under low velocity impact both experimentally and numerically. With this aim, the effects of wide range impact energy values between 10 J and 60 J were evaluated experimentally and numerically for the laminate of [±45/(0/90)2]S oriented unidirectional E-glass as reinforcing material and epoxy resin for matrix material. Different impactor velocities were used to maintain the impact energy values and experimental impact tests were generated with drop weight impact testing machine at room temperature. Numerical simulations were performed using LS-DYNA finite element analysis software with a continuum damage mechanics-based material model MAT058. Contact force between impactor and laminate, and transverse deflection at the center of laminate results were obtained as a function of time and used to plot contact force–time curves, contact force–deflection curves and absorbed energy-impact energy curves. Also, delamination area was examined. Finally, numerical results were compared with experimental results and a good correlation between them was observed.

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