Microstructure and Mechanical Properties of Inconel718-NiCrAlY Composites Prepared by Laser Engineered Net Shaping

2018 ◽  
Vol 20 (4) ◽  
pp. 1701043 ◽  
Author(s):  
Guohui Zhang ◽  
Shuai Yan ◽  
Fangyong Niu ◽  
Guangyi Ma ◽  
Dongjiang Wu ◽  
...  
Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 603
Author(s):  
Natalia Rońda ◽  
Krzysztof Grzelak ◽  
Marek Polański ◽  
Julita Dworecka-Wójcik

This work investigates the effect of layer thickness on the microstructure and mechanical properties of M300 maraging steel produced by Laser Engineered Net Shaping (LENS®) technique. The microstructure was characterized using light microscopy (LM) and scanning electron microscopy (SEM). The mechanical properties were characterized by tensile tests and microhardness measurements. The porosity and mechanical properties were found to be highly dependent on the layer thickness. Increasing the layer thickness increased the porosity of the manufactured parts while degrading their mechanical properties. Moreover, etched samples revealed a fine cellular dendritic microstructure; decreasing the layer thickness caused the microstructure to become fine-grained. Tests showed that for samples manufactured with the chosen laser power, a layer thickness of more than 0.75 mm is too high to maintain the structural integrity of the deposited material.


Author(s):  
Fuda Ning ◽  
Yingbin Hu ◽  
Zhichao Liu ◽  
Xinlin Wang ◽  
Yuzhou Li ◽  
...  

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.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7302
Author(s):  
Izabela Barwinska ◽  
Mateusz Kopec ◽  
Magdalena Łazińska ◽  
Adam Brodecki ◽  
Tomasz Durejko ◽  
...  

In this paper, the Inconel 625 laser clads characterized by microstructural homogeneity due to the application of the Laser Engineered Net Shaping (LENS, Optomec, Albuquerque, NM, USA) technology were studied in detail. The optimized LENS process parameters (laser power of 550 W, powder flow rate of 19.9 g/min, and heating of the substrate to 300 °C) enabled to deposit defect-free laser cladding. Additionally, the laser clad was applied in at least three layers on the repairing place. The deposited laser clads were characterized by slightly higher mechanical properties in comparison to the Inconel 625 substrate material. Microscopic observations and X-ray Tomography (XRT, Nikon Corporation, Tokyo, Japan) confirmed, that the substrate and cladding interface zone exhibited a defect-free structure. Mechanical properties and flexural strength of the laser cladding were examined using microhardness and three-point bending tests. It was concluded, that the LENS technology could be successfully applied for the repair since a similar strain distribution was found after Digital Image Correlation measurements during three-point bending tests.


Author(s):  
Allen Bagheri ◽  
Nima Shamsaei ◽  
Scott M. Thompson

Laser Engineered Net Shaping (LENS®) is a Direct Laser Deposition (DLD) additive manufacturing technology that can be used for directly building complex 3D components from metal powders in a combined deposition/laser-melting process. In this study, the effect of LENS process parameters, such as laser power, powder feed rate and traverse speed, on the resultant microstructure, hardness and tensile strength of Ti-6Al-4V components is experimentally investigated. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) are used to characterize the microstructure in terms of grain size and morphology. Relationships between process parameters and the microstructural/mechanical properties are provided. Results indicate that the scale of columnar grains increases with slower laser traverse speeds while other process parameters are maintained constant. The size of the α and β laths increases with higher laser powers and slower traverse speeds. The ultimate tensile and yield strengths of the LENS specimens were found to be higher than those of cast and wrought materials, and this can be generally attributed to the different cooling rates inherent to LENS — which impacts grain size. The percent elongation to failure, however, was consistently lower than that of the wrought material.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2827 ◽  
Author(s):  
Damian Kalita ◽  
Łukasz Rogal ◽  
Piotr Bobrowski ◽  
Tomasz Durejko ◽  
Tomasz Czujko ◽  
...  

The effect of Nb content on microstructure, mechanical properties and superelasticity was investigated for a series of Ti-xNb alloys, fabricated by the laser engineered net shaping method, using elemental Ti and Nb powders. The microstructure of as-deposited materials consisted of columnar β-phase grains, elongated in the built direction. However, due to the presence of undissolved Nb particles during the deposition process, an additional heat treatment was necessary. The observed changes in mechanical properties were explained in relation to the phase constituents and deformation mechanisms. Due to the elevated oxygen content in the investigated materials (2 at.%), the specific deformation mechanisms were observed at lower Nb content in comparison to the conventionally fabricated materials. This made it possible to conclude that oxygen increases the stability of the β phase in β–Ti alloys. For the first time, superelasticity was observed in Ti–Nb-based alloys fabricated by the additive manufacturing method. The highest recoverable strain of 3% was observed in Ti–19Nb alloy as a result of high elasticity and reverse martensitic transformation stress-induced during the loading.


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