A fundamental investigation on ultrasonic vibration-assisted laser engineered net shaping of stainless steel

2017 ◽  
Vol 121 ◽  
pp. 61-69 ◽  
Author(s):  
Weilong Cong ◽  
Fuda Ning
Keyword(s):  
Stainless Steel ◽  
Ultrasonic Vibration ◽  
Laser Engineered Net Shaping ◽  
Fundamental Investigation ◽  
Net Shaping

Microstructure and mechanical property of TiB reinforced Ti matrix composites fabricated by ultrasonic vibration-assisted laser engineered net shaping

2019 ◽  
Vol 25 (3) ◽  
pp. 581-591 ◽  
Author(s):  
Fuda Ning ◽  
Yingbin Hu ◽  
Weilong Cong
Keyword(s):  
Ultrasonic Vibration ◽  
Acoustic Streaming ◽  
Nonlinear Effects ◽  
Small Variation ◽  
Microstructural Characterization ◽  
Matrix Composites ◽  
Heterogeneous Distribution ◽  
Content Type ◽  
Laser Engineered Net Shaping ◽  
Net Shaping

Purpose The purpose of this paper is to identify if the implementation of ultrasonic vibration in laser engineered net shaping (LENS) process can help to reduce internal weaknesses such as porosity, coarse primary TiB whisker and heterogeneous distribution of TiB reinforcement in the LENS-fabricated TiB reinforced Ti matrix composites (TiB-TMC) parts. Design/methodology/approach An experimental investigation is performed to achieve the results for comparative studies under different fabrication conditions through quantitative data analysis. An approach of microstructural characterization and mechanical testing is conducted to obtain the output attributes. In addition, the theoretical analysis of the physics of ultrasonic vibration in the melting materials is presented to explain the influences of ultrasonic vibration on the microstructural evolution occurred in the part fabrication. Findings Because of the nonlinear effects of acoustic streaming and cavitation induced by ultrasonic vibration, porosity is significantly reduced and a relatively small variation of pore sizes is achieved. Ultrasonic vibration also causes the formation of smaller TiB whiskers that distribute along grain boundaries with a homogeneous dispersion. Additionally, a quasi-continuous network (QCN) microstructure is considerably finer than that produced by LENS process without ultrasonic vibration. The refinements of both reinforcing TiB whiskers and QCN microstructural grains further improve the microhardness of TiB-TMC parts. Originality/value The novel ultrasonic vibration-assisted (UV-A) LENS process of TiB-TMC is conducted in this work for the first time to improve the process performance and part quality.

Ultrasonic Vibration-Assisted Laser Engineered Net Shaping of Inconel 718 Parts: Microstructural and Mechanical Characterization

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Fuda Ning ◽  
Yingbin Hu ◽  
Zhichao Liu ◽  
Xinlin Wang ◽  
Yuzhou Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Vibration ◽  
Inconel 718 ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Laser Engineered Net Shaping ◽  
Average Grain Size ◽  
Fabrication Defects ◽  
Heterogeneous Microstructures ◽  
Net Shaping

Laser engineered net shaping (LENS) has become a promising technology in direct manufacturing or repairing of high-performance metal parts. Investigations on LENS manufacturing of Inconel 718 (IN718) parts have been conducted for potential applications in the aircraft turbine component manufacturing or repairing. Fabrication defects, such as pores and heterogeneous microstructures, are inevitably induced in the parts, affecting part qualities and mechanical properties. Therefore, it is necessary to investigate a high-efficiency LENS process for the high-quality IN718 part fabrication. Ultrasonic vibration has been implemented into various melting material solidification processes for part performance improvements. However, there is a lack of studies on the utilization of ultrasonic vibration in LENS process for IN718 part manufacturing. In this paper, ultrasonic vibration-assisted (UV-A) LENS process is, thus, proposed to fabricate IN718 parts for the potential reduction of fabrication defects. Experimental investigations are conducted to study the effects of ultrasonic vibration on microstructures and mechanical properties of LENS-fabricated parts under two levels of laser power. The results showed that ultrasonic vibration could reduce the mean porosity to 0.1%, refine the microstructure with an average grain size of 5 μm, and fragment the detrimental Laves precipitated phase into small particles in a uniform distribution, thus enhancing yield strength, ultimate tensile strength (UTS), microhardness, and wear resistance of the fabricated IN718 parts.

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.

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