The Studies on Multiaxial Creep Behavior of Inconel 718 Notched Bar at 700 °C

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Shiyi Bao ◽  
Zhongyang Xiao ◽  
Xiangyang Li ◽  
Fengping Zhong ◽  
Jianfeng Mao
Keyword(s):  
Creep Test ◽  
Creep Behavior ◽  
Inconel 718 ◽  
Volume Fraction ◽  
Axial Stress ◽  
Stress Triaxiality ◽  
Numerical Data ◽  
Inconel 718 Alloy ◽  
Strain Stress ◽  
Multiaxial Creep

Abstract This paper studies the multi-axial creep behavior of Inconel 718 alloy at 700 °C. The stress triaxiality was introduced into the sample by adding U-shaped notches of various sizes and shapes. Furthermore, the multi-axial creep test of notched round bar was completed, and the sample slice after the creep test was subjected to scanning electron microscopy (SEM) microscopic examination. The influence of notch radius on its creep behavior and damage evolution was studied through experimental and numerical investigation. The finite element method (FEM) implemented by Gurson–Tvergaard–Needleman (GTN) model is used to simulate the evolution of damage in multi-axial stress state. With the comparison between experimental and numerical data, the multi-axial creep behaviors are clearly revealed in terms of stress triaxiality, creep strain (stress), void volume fraction (VVF), and so on. It was found that the great agreement is achieved between FEM and test data, and multi-axial creep behavior is well predicted.

scholarly journals TEM Study of High-Temperature Precipitation of Delta Phase in Inconel 718 Alloy

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Moukrane Dehmas ◽  
Jacques Lacaze ◽  
Aliou Niang ◽  
Bernard Viguier
Keyword(s):  
Inconel 718 ◽  
Volume Fraction ◽  
Alloy 718 ◽  
Double Diffraction ◽  
X Ray Diffraction ◽  
Inconel 718 Alloy ◽  
X Ray ◽  
Delta Phase ◽  
Transmission Electron ◽  
Matrix Free

Inconel 718 is widely used because of its ability to retain strength at up to 650∘C for long periods of time through coherent metastable Ni3Nb precipitation associated with a smaller volume fraction of Ni3Al precipitates. At very long ageing times at service temperature, decomposes to the stable Ni3Nb phase. This latter phase is also present above the solvus and is used for grain control during forging of alloy 718. While most works available on precipitation have been performed at temperatures below the solvus, it appeared of interest to also investigate the case where phase precipitates directly from the fcc matrix free of precipitates. This was studied by X-ray diffraction and transmission electron microscopy (TEM). TEM observations confirmed the presence of rotation-ordered domains in plates, and some unexpected contrast could be explained by double diffraction due to overlapping phases.

scholarly journals Effect of Initial Porosity on Material Response Under Multi-Axial Stress State for S235JR Steel

2012 ◽  
Vol 58 (4) ◽  
pp. 445-462 ◽  
Author(s):  
P.G. Kossakowski
Keyword(s):  
Stress State ◽  
Volume Fraction ◽  
Axial Stress ◽  
High Stress ◽  
Stress Triaxiality ◽  
Material Model ◽  
Initial Porosity ◽  
Safety Level ◽  
Material Response ◽  
Average Porosity

AbstractThe effect of the initial porosity on the material response under multi-axial stress state for S235JR steel using the Gurson-Tvergaard-Needleman (GTN) material model was examined. Three levels of initial porosity, defined by the void volume fraction f0, were considered: zero porosity for fully dense material without pores, average and maximum porosity according to the metallurgical requirements for S235JR steel. The effect of the initial porosity on the material response was noticed for tensile elements under multi-axial stress state defined by high stress triaxiality σm/σe = 1.345. This effect was especially noticeable at the range of the material failure. In terms of the load-bearing capacity of the elements, the conservative results were obtained when maximum value of f0 = 0.0024 was used for S235JR steel under multi-axial stress state, and this value is recommended to use in the calculations in order to preserve the highest safety level of the structure. In usual engineering calculations, the average porosity defined by f0 = 0.001 may be applied for S235JR.

scholarly journals A Comparative Analysis of Laser Additive Manufacturing of High Layer Thickness Pure Ti and Inconel 718 Alloy Materials Using Finite Element Method

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 876 ◽  
Author(s):  
Sapam Ningthemba Singh ◽  
Sohini Chowdhury ◽  
Yadaiah Nirsanametla ◽  
Anil Kumar Deepati ◽  
Chander Prakash ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Layer Thickness ◽  
Inconel 718 ◽  
Laser Power ◽  
Scanning Speed ◽  
Laser Additive Manufacturing ◽  
Inconel 718 Alloy ◽  
Melt Pool ◽  
High Layer

Investigation of the selective laser melting (SLM) process, using finite element method, to understand the influences of laser power and scanning speed on the heat flow and melt-pool dimensions is a challenging task. Most of the existing studies are focused on the study of thin layer thickness and comparative study of same materials under different manufacturing conditions. The present work is focused on comparative analysis of thermal cycles and complex melt-pool behavior of a high layer thickness multi-layer laser additive manufacturing (LAM) of pure Titanium (Ti) and Inconel 718. A transient 3D finite-element model is developed to perform a quantitative comparative study on two materials to examine the temperature distribution and disparities in melt-pool behaviours under similar processing conditions. It is observed that the layers are properly melted and sintered for the considered process parameters. The temperature and melt-pool increases as laser power move in the same layer and when new layers are added. The same is observed when the laser power increases, and opposite is observed for increasing scanning speed while keeping other parameters constant. It is also found that Inconel 718 alloy has a higher maximum temperature than Ti material for the same process parameter and hence higher melt-pool dimensions.

Corrosion Behavior of a Selective Laser Melted Inconel 718 Alloy in a 3.5 wt.% NaCl Solution

2021 ◽  
Author(s):  
Yanbing Tang ◽  
Xinwang Shen ◽  
Yanxin Qiao ◽  
Lanlan Yang ◽  
Jian Chen ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Inconel 718 ◽  
Nacl Solution ◽  
Inconel 718 Alloy

scholarly journals Very-High-Cycle Fatigue Behavior of Inconel 718 Alloy Fabricated by Selective Laser Melting at Elevated Temperature

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1001
Author(s):  
Zongxian Song ◽  
Wenbin Gao ◽  
Dongpo Wang ◽  
Zhisheng Wu ◽  
Meifang Yan ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Selective Laser Melting ◽  
Fatigue Resistance ◽  
Inconel 718 ◽  
High Cycle Fatigue ◽  
Cycle Fatigue ◽  
Laser Melting ◽  
Inconel 718 Alloy ◽  
Very High Cycle Fatigue ◽  
Very High

This study investigates the very-high-cycle fatigue (VHCF) behavior at elevated temperature (650 °C) of the Inconel 718 alloy fabricated by selective laser melting (SLM). The results are compared with those of the wrought alloy. Large columnar grain with a cellular structure in the grain interior and Laves/δ phases precipitated along the grain boundaries were exhibited in the SLM alloy, while fine equiaxed grains were present in the wrought alloy. The elevated temperature had a minor effect on the fatigue resistance in the regime below 108 cycles for the SLM alloy but significantly reduced the fatigue strength in the VHCF regime above 108 cycles. Both the SLM and wrought specimens exhibited similar fatigue resistance in the fatigue life regime of fewer than 107–108 cycles at elevated temperature, and the surface initiation mechanism was dominant in both alloys. In a VHCF regime above 107–108 cycles at elevated temperature, the wrought material exhibited slightly better fatigue resistance than the SLM alloy. All fatigue cracks are initiated from the internal defects or the microstructure discontinuities. The precipitation of Laves and δ phases is examined after fatigue tests at high temperatures, and the effect of microstructure on the formation and the propagation of the microstructural small cracks is also discussed.

Microstructure and Wear Properties of Laser-clad NiCo Alloy Coating on Inconel 718 Alloy

2021 ◽  
pp. 160412
Author(s):  
Tao Wang ◽  
Chao Wang ◽  
Juanjuan Li ◽  
Linjiang Chai ◽  
Xing Hu ◽  
...  
Keyword(s):  
Inconel 718 ◽  
Alloy Coating ◽  
Wear Properties ◽  
Inconel 718 Alloy
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