Assessing the Feasibility of Micro-Plasma Technology for Additive Manufacturing

Author(s):  
Jason Nagy ◽  
Xiao Huang

In this research, a micro-plasma system was investigated for its capability in additive manufacturing (AM). Micro-plasma AM system has the advantage of lower cost and higher deposition rate over laser based AM systems, and generates leaner and cleaner weld deposit than other arc based AM systems. However, the micro-plasma system is complex and involves a large number of process variables. In this study, the feasibility of using a micro-plasma system for additive manufacturing was assessed based on surface features, mechanical properties and microstructure. In addition, two arc and wire feed modes were examined to understand the effects of these two variables. Each was used to produce IN 718 superalloy samples for macro- and microstructure evaluation, hardness, wear, and tensile tests along both long and transverse directions. Preliminary results showed that crack free samples, measured up to 100 mm × 40 mm, can be generated without measurable distortion. Some surface discoloration was observed, ranging from light straw to a purple tint. After heat treatment, the hardness of the samples varies from 403 to 440 HV, with the transverse surface showing slightly lower hardness values. Pin-on-disk wear test yielded consistent wear volume for three sets of the samples produced using different process parameters; however, samples produced with no modifications to the current and wire feed mode showed marginally higher wear rate. Microstructural analysis with SEM and EDS revealed presence of small pinholes, measured from submicron up to 22 μm in diameter, and no indication of any cracks or boundary layers between passes. SEM analysis revealed the presence of high contrast Nb/Mo rich carbides along with γ″-Ni3Nb in the γ matrix. Finally, tensile test was carried out to understand the anisotropic behavior; the results showed that transverse direction had lower tensile strength and ductility. Samples produced with pulsed current and wire feed mode had lower yield/tensile strength but higher ductility than that without current and wire feed mode modification.

Author(s):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.


Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1246
Author(s):  
Shih-Chen Shi ◽  
Tao-Hsing Chen ◽  
Pramod Kumar Mandal

Hydroxypropyl methylcellulose (HPMC) is a common hydrophilic and biodegradable polymer that can form films. This study incorporated aluminum nanoadditives as an enhancement reagent into a HPMC matrix. Mechanical properties of nanocompoistes, including the tensile strength and the elastic modulus, were analyzed with a nano-tensile tester. The incorporation of additives in HPMC films significantly enhances their mechanical and film barrier properties. Evidence of bonding between the additive and matrix was observed by Fourier-transform infrared spectrometer analysis. The additives occupy the spaces in the pores of the matrix, which increases the tendency of the pore to collapse and improves the chemical bonding between the base material and the additives. The incorporation of excess additives decreases the tensile strength due to ineffective collisions between the additives and the matrix. The wear test proves that the addition of nano-additives can improve the tribology performance of the HPMC composite while reducing the wear volume and the friction. Bonding between the nanoadditives and the matrix does not help release the nanoadditives into the wear interface as a third-body layer. The main reason to enhance the tribology performance is that the nanoadditives improve the load-capacity of the composite coating. This hybrid composite can be useful in many sustainability applications.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Hamaid M. Khan ◽  
Tolga B. Sirin ◽  
Gurkan Tarakci ◽  
Mustafa E. Bulduk ◽  
Mert Coskun ◽  
...  

Abstract This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials. Graphic abstract


2020 ◽  
Vol 26 (3) ◽  
pp. 127-130
Author(s):  
Nassim Markiz ◽  
Eszter Horváth ◽  
Péter Ficzere

AbstractIn the recent years, additive manufacturing became an interesting topic in many fields due to the ease of manufacturing complex objects. However, it is impossible to determine the mechanical properties of any additive manufacturing parts without testing them. In this work, the mechanical properties with focus on ultimate tensile strength and modulus of elasticity of 3D printed acrylonitrile butadi-ene styrene (ABS) specimens were investigated. The tensile tests were carried using Zwick Z005 loading machine with a capacity of 5KN according to the American Society for Testing and Materials (ASTM) D638 standard test methods for tensile properties of plastics. The aim of this study is to investigate the influence of printing direction on the mechanical properties of the printed specimens. Thus, for each printing direction ( and ), five specimens were printed. Tensile testing of the 3D printed ABS specimens showed that the printing direction made the strongest specimen at an ultimate tensile strength of 22 MPa while at printing direction it showed 12 MPa. No influence on the modulus of elasticity was noticed. The experimental results are presented in the manuscript.


2021 ◽  
Author(s):  
Kyle Koren ◽  
Toluwalase Olajoyegbe ◽  
Beshoy Morkos ◽  
Hector Gutierrez

Abstract The adoption of additive manufacturing methods is becoming prevalent in industry. Socio-economic trends seek more customization and sustainability in production. An increase in unique service components will warrant the need for more flexible repair methods. This is particularly important for components that are difficult to access or disassemble — thus requiring an on-site repair. This paper introduces the use of 3D printing pens as a means to perform repair to additively manufacturing components. A study was conducted to assess the feasibility of using a 3D printing pen in maintenance, repair and overhaul (MRO) applications on polymer-based service products. A series of tensile tests were conducted on printed specimens, pre- and post-repair, to examine the tensile retention of the mended region. Results indicate significant retention in tensile strength in the mended specimens, supporting the notion of the pens relevance in repair and overhaul applications. Specimens that fractured within the repair region were seen to have retained (81 ± 10) % of their original tensile strength while specimens that fractured outside the region retained (86 ± 4) %. Considering the limited control of the study, results acquired encourage further analysis of the underlying mechanisms in the process, with the intent to more efficiently exploit this approach for practical structure-based repair applications.


2021 ◽  
Author(s):  
Xiaojing Yuan ◽  
Ning Guan ◽  
Xuping Wang ◽  
Hao Li ◽  
Jin Li ◽  
...  

Abstract An innovative pulsed micro-plasma additive manufacturing (AM) system is proposed for the fabrication of thin-walled 316 stainless steel parts. During the deposition process, the heat accumulation from the micro-plasma can be controlled effectively by adjusting the following parameters: the AM current, pulse length of the plasma arc, and scanning speed. The width of the pool can reach 3.0 mm. The microstructural analysis, micro-hardness tests, and tensile strength tests were performed. The results of the structural characterisation showed that columnar dendrites predominated in the microstructure of thin-walled elements and exhibited epitaxial growth from the bottom to the top and from the middle to both sides, while the top grains had more variations in growth orientation. The grains had a core-shell structure with a growth orientation along the < 100 > direction of the austenite structure, and the boundary was composed of migrated C and Cr. The micro-hardness of the thin-walled structure (240–320 Hv0.3) decreased with increasing the deposition thickness. The tensile strength and yield strength of the thin-walled parts were 669 and 475 MPa, respectively. The fracture mechanism was that cracks formed along the pores along the pores of the grain boundary and then propagated along them, ultimately leading to the fracture.


Vestnik MEI ◽  
2017 ◽  
pp. 8-14 ◽  
Author(s):  
Aleksandr V. Gudenko ◽  
◽  
Viktor К. Dragunov ◽  
Andrey Р. Sliva ◽  
◽  
...  

2011 ◽  
Vol 66-68 ◽  
pp. 1207-1212 ◽  
Author(s):  
Mohd Sayuti ◽  
Shamsuddin Sulaiman ◽  
B.T. Hang Tuah Baharudin ◽  
M.K.A.M. Arifin ◽  
T.R. Vijayaram ◽  
...  

Vibrational moulding process has a remarkable effect on the properties of castings during solidification processing of metals, alloys, and composites. This research paper discusses on the investigation of mechanical vibration mould effects on the tensile properties of titanium carbide particulate reinforced LM6 aluminium alloy composites processed with the frequencies of 10.2 Hz, 12 Hz and 14 Hz. In this experimental work, titanium carbide particulate reinforced LM6 composites were fabricated by carbon dioxide sand moulding process. The quantities of titanium carbide particulate added as reinforcement in the LM6 alloy matrix were varied from 0.2% to 2% by weight fraction. Samples taken from the castings and tensile tests were conducted to determine the tensile strength and modulus of elasticity. The results showed that tensile strength of the composites increased with an increase in the frequency of vibration and increasing titanium carbide particulate reinforcement in the LM6 alloy matrix.


2021 ◽  
Vol 58 (1) ◽  
pp. 4-31
Author(s):  
C. Fleißner-Rieger ◽  
T. Pogrielz ◽  
D. Obersteiner ◽  
T. Pfeifer ◽  
H. Clemens ◽  
...  

Abstract Additive manufacturing processes allow the production of geometrically complex lightweight structures with specific material properties. However, by contrast with ingot metallurgy methods, the manufacture of components using this process also brings about some challenges. In the field of microstructural characterization, where mostly very fine structures are analyzed, it is thus indispensable to optimize the classic sample preparation process and to furthermore implement additional preparation steps. This work focuses on the metallography of additively manufactured Ti‑6Al‑4V components produced in a selective laser melting process. It offers a guideline for the metallographic preparation along the process chain of additive manufacturing from the metal powder characterization to the macro- and microstructural analysis of the laser melted sample. Apart from developing preparation parameters, selected etching methods were examined with regard to their practicality.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.


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