scholarly journals Effect of Initial Temperature on the Microstructure and Properties of Stellite-6/Inconel 718 Functional Gradient Materials Formed by Laser Metal Deposition

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3609
Author(s):  
Jun Yao ◽  
Bo Xin ◽  
Yadong Gong ◽  
Guang Cheng

Stelite-6/Inconel 718 functionally gradient materials (FGM) is a heat-resisting functional gradient material with excellent strength performance under ultra-high temperatures (650–1100 °C) and, thus, has potential application in aeronautic and aerospace engineering such as engine turbine blade. To investigate the effect of initial temperature on the microstructure and properties of laser metal deposition (LMD) functional gradient material (FGM), this paper uses the LMD technique to form Stelite-6/Inconel 718 FGM at two different initial temperatures: room temperature and preheating (300 °C). Analysis of the internal residual stress distribution, elemental distribution, microstructure, tensile properties, and microhardness of 100% Stelite-6 to 100% Inconel 718 FGM formed at different initial temperatures in a 10% gradient. The experimental results prove that the high initial temperature effectively improves the uneven distribution of internal residual stresses. Preheating slows down the solidification time of the melt pool and facilitates the escape of gases and the homogeneous diffusion of elements in the melt pool. In addition, preheating reduces the bonding area between the gradient layers, enhancing the metallurgical bonding properties between the layers and improving the tensile properties. Compared with Stellite-6/Inconel 718 FGM formed at room temperature, the mean yield strength, mean tensile strength, and mean elongation of Stellite-6/Inconel 718 FGM formed at 300 °C are increased by 65.1 Mpa, 97 MPa, and 5.2%. However, the high initial temperature will affect the hardness of the material. The average hardness of Stellite-6/Inconel 718 FGM formed at 300 °C is 26.9 HV (Vickers hardness) lower than that of Stellite-6/Inconel 718 FGM formed at 20 °C.

2018 ◽  
Vol 226 ◽  
pp. 01014
Author(s):  
Vadim V. Eremeev ◽  
Denis V. Ivashchenko

Within the 3D nonlinear elasticity we discuss the linear instability of a composite bar made of a functially graded material and having initial stresses. The bar consists of two layers which are inflated for a annular wedge of a circular cylinder. We present the linearized boundary0value problem and obtain its non-trivial solutions. The influence of the material inhomogeneity and the initial stresses are discussed.


2013 ◽  
Vol 834-836 ◽  
pp. 1571-1574
Author(s):  
Qun Qin ◽  
Guang Xia Chen

The primary goal of this research is the development of software system about functional gradient material process by laser. The system can be divided into several modules such as STL file loading and viewing, model slicing, filling path planning and process controlling. Path planning of FGM area is one key technology of system development because of one path must contain material information of functional gradient material. The material information planning methods of one-dimension and two-dimension functional gradient material were described respectively in this article. The material information of one-dimension FGM changes by layer along Z-axis, and the material information of two-dimension FGM changes by path in X-Y plane, especially, there is different change direction of FGM between inner loop and outer loop.


2017 ◽  
Vol 868 ◽  
pp. 151-157
Author(s):  
Xiao Peng Li ◽  
Yuan Gang Wang ◽  
Fu Ling Zhao ◽  
Meng Hua Wu

The concept and the primary preparation method of functional gradient materials are described in this paper. Functional gradient material is prepared as a tool electrode by electrochemical method and its performance is further tested in the micro electrical discharge machining (micro-EDM) experiments. Compared with the homogeneous material electrode, the functional gradient material electrode can effectively inhibit the wearing of the tool electrode and improve the distribution trend of current density during the micro-EDM process. The results disclose the prospects for functional gradient material to be used as tool electrode in the micro-EDM process.


Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 62 ◽  
Author(s):  
Yu Zhang ◽  
Zhanqi Cheng ◽  
Hu Feng

Functional gradient materials (FGMs) have tremendous potential due to their characteristic advantage of asymptotic continuous variation of their properties. When an FGM is used as a coating material, damage and failure of the interface with the substrate component can be effectively inhibited. In order to study the dynamic crack propagation in FGM coatings, a new method, peridynamics (PD), was used in the present study to simulate dynamic fractures of FGM coatings bonded to a homogeneous substrate under dynamic loading. The bond-based PD theory was employed to study crack propagation and branching in the FGM coating. The influences of the coating gradient pattern, loading, and the geometry and size of the structure on crack curving and propagation under impact loading were investigated. The numerical results show that different forms of the elastic modulus of graded material, the geometry of the structure, and the loading conditions have considerate effects on crack propagation in FGM coatings, but a specific form of elastic modulus had a limited effect on the dynamic fracture of FGM coating.


2003 ◽  
Vol 249 ◽  
pp. 105-108 ◽  
Author(s):  
Zheng Yi Fu ◽  
J.P. Liu ◽  
Jin Yong Zhang ◽  
Qing Jie Zhang

Author(s):  
Eteri Hart ◽  
Terokhin Bohdan

Computer simulation of the stress-strain state of a thin rectangular homogeneous isotropic plate with a circular hole, reinforced by an annular inclusion made of a functional-gradient material (FGM) has been carried out. The influence of the geometric (width) and mechanical (elastic modulus) parameters of the inclusion is investigated when various laws of change in the elastic modulus of the FGM are set on the stress concentration around the hole. Recommendations for the use of inclusions are given. If there is a "hard" annular inclusion in a homogeneous plate with a hole, it is expedient to use an FGM with a nonlinear law of change in the modulus of elasticity in comparison with an inclusion made of a homogeneous material. Despite the fact that the inclusion leads to a slight increase in the stress concentration factor in comparison with a homogeneous material, it makes it possible to increase the rigidity of the system as a whole. The width of FGM inclusions affects the nature of the stress distribution: the wider the inclusion, the more smoothly the stress redistribution in the main matrix occurs.


2015 ◽  
Vol 34 (5) ◽  
Author(s):  
Siwen Tang ◽  
Deshun Liu ◽  
Pengnan Li ◽  
Yuqiang Chen ◽  
Xiong Xiao

AbstractThe interaction between nitrogen and titanium carbonitride (Ti(C,N))-based cermets by microwave heating was applied to develop functional gradient cermets. Ti(C,N)-based cermets was densification and nitrided simultaneously above the eutectic temperature, which greatly shortens the sintering time. Experimental results show that a face centered cubic (fcc) rich surface layer was formed at the surface of the cermets. Meanwhile, a new three layers core/rim structure was found in the cermets and its formation mechanism was proposed in this study. The functional gradient material exhibits excellent comprehensive properties.


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