scholarly journals Comparative Quality Control of Titanium Alloy Ti–6Al–4V, 17–4 PH Stainless Steel, and Aluminum Alloy 4047 Either Manufactured or Repaired by Laser Engineered Net Shaping (LENS)

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4171 ◽  
Author(s):  
Noam Eliaz ◽  
Nitzan Foucks ◽  
Dolev Geva ◽  
Shai Oren ◽  
Noy Shriki ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
High Standard ◽  
Micro Computed Tomography ◽  
Laser Engineered Net Shaping ◽  
Ct Analysis ◽  
Powder Particles ◽  
Structural Parts ◽  
Net Shaping ◽  
Roughness Measurements

Additive manufacturing attracts much interest for manufacturing and repair of structural parts for the aerospace industry. This paper presents comparative characterization of aircraft items made of Al 4047 alloy, Ti-6Al-4V alloy, and 17-4 precipitation hardened (PH) (AISI 630) stainless steel, either manufactured or repaired by laser engineered net shaping (LENS). Chemical analysis, density, and surface roughness measurements, X-ray micro-computed tomography (μ-CT) analysis, metallography, and micro-hardness testing were conducted. In all three materials, microstructures typical of rapid solidification were observed, along with high density, chemical composition, and hardness comparable to those of the counterpart wrought alloys (even in hard condition). High standard deviation in hardness values, anisotropic geometrical distortion, and overbuild at top edges were observed. The detected defects included partially melted and unmelted powder particles, porosity, and interlayer lack of fusion, in particular at the interface between the substrate plate and the build. There was a fairly good match between the density values measured by μ-CT and those measured by the Archimedes method; there was also good correlation between the type of defects detected by both techniques. Surface roughness, density of partially melted powder particles, and the content of bulk defects were significantly higher in Al 4047 than in 17-4 PH stainless steel and Ti-6Al-4V alloy. Optical gaging can be used reliably for surface roughness measurements. The implications of these findings are discussed.

Surface Grinding of ZTA Parts Fabricated by Laser Engineered Net Shaping Process: Effects of ZrO2 Content and Ultrasonic Vibration

2018 ◽  
Author(s):  
Yingbin Hu ◽  
Hui Wang ◽  
Yuanchen Li ◽  
Fuda Ning ◽  
Weilong Cong
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Surface Quality ◽  
Ultrasonic Vibration ◽  
Machining Process ◽  
Ultrasonic Machining ◽  
Zro2 Content ◽  
Laser Engineered Net Shaping ◽  
Process Effects ◽  
Net Shaping

The zirconia toughened alumina (ZTA) parts fabricated by laser engineered net shaping (LENS) process demonstrate problems resulted from poor surface quality. To improve surface quality and to reduce related problems, rotary ultrasonic machining (RUM) process, which combines both grinding process and ultrasonic machining process, has been introduced. In this investigation, the effects of ZrO2 content and ultrasonic vibration on flatness, surface roughness, microhardness, and cutting force in feeding direction of LENS-fabricated ZTA parts have been studied. Results showed that with the ZrO2 content increasing, the flatness value increased, the surface roughness value decreased, and the microhardness value firstly increased then decreased. Compared with LENS-fabricated parts, the parts processed by RUM machine exhibited better surface quality with significantly reduced flatness value and surface roughness value. In RUM process, the introduction of ultrasonic vibration was beneficial for reducing cutting force.

A Study on Laser Engineered Net Shaping Prototyping Technology

2007 ◽  
Author(s):  
Z. Xu ◽  
R. S. Amano ◽  
J. M. Lucci ◽  
Steven Gerard Marek ◽  
Pradeep Rohatgi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Stainless Steel ◽  
Numerical Method ◽  
Cooling Rate ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Point Of View ◽  
Simplified Models ◽  
Laser Engineered Net Shaping ◽  
Net Shaping

The objectives of this work are to study Laser Engineered Net Shaping (LENS™) produced materials and identify the microstructures. Numerical method was used to examine the influence of materials’ type and LENS™ process parameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of 316L stainless steel were examined, microstructures of samples were used to estimate the corresponding cooling rate, and the cooling rate was compared with the results of three different level of simplified models.

Fabrication of SS316L/Ni25 Functionally Gradient Materials Using Laser Engineered Net Shaping

2011 ◽  
Vol 675-677 ◽  
pp. 803-806 ◽  
Author(s):  
Dong Jiang Wu ◽  
Xiao Kang Liang ◽  
Qian Li ◽  
Li Jia Jiang
Keyword(s):  
Stainless Steel ◽  
Columnar Dendrite ◽  
Composition Analysis ◽  
Functionally Gradient Materials ◽  
Stainless Steel 316L ◽  
Equiaxed Dendrite ◽  
Gradient Materials ◽  
Laser Engineered Net Shaping ◽  
Functionally Gradient ◽  
Net Shaping

Functionally gradient materials(FGMs) were successfully fabricated with compositions gradually changed from 100% stainless steel 316L to 100% Ni25 alloy using laser engineered net shaping(LENS) technology. The microstructure characterization, composition analysis and microhardness along the gradient direction are investigated. Meanwhile, the defects in the sample such as cracks and pores are analyzed. The results indicated that the microstructure evolves from columnar dendrite to cellular-crystal or equiaxed dendrite.

scholarly journals Corrosion Characteristics of Laser-Engineered Net Shaping Additively-Manufactured 316L Stainless Steel

JOM ◽  
2018 ◽  
Vol 70 (11) ◽  
pp. 2677-2683 ◽  
Author(s):  
Jamie A. Stull ◽  
Mary Ann Hill ◽  
Thomas J. Lienert ◽  
Justin Tokash ◽  
Kevin R. Bohn ◽  
...  
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Laser Engineered Net Shaping ◽  
Net Shaping

Numerical Modeling of Grain Growth in Laser Engineered Net Shaping (LENS) of AISI 316 Stainless Steel

2017 ◽  
Author(s):  
Wenda Tan ◽  
Xuxiao Li
Keyword(s):  
Stainless Steel ◽  
Grain Growth ◽  
Molten Pool ◽  
Grain Structure ◽  
Scale Model ◽  
Modeling Framework ◽  
Laser Engineered Net Shaping ◽  
Macro Scale ◽  
Aisi 316 ◽  
Net Shaping

A multi-scale modeling framework is developed in this work to simulate the transport phenomena and grain growth in Laser Engineered Net Shaping (LENS) process of austenitic stainless steel AISI 316. A three-dimensional (3D) model is included to simulate the transient molten pool geometry and heat/mass transfer on a macro-scale; and a 3D meso-scale model based on the Cellular Automata method is included to predict the grain growth during molten pool solidification. The predicted grain structure is found to be consistent with the experimental results and reveals that the grain structure is highly dependent on the molten pool geometry.

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