The Role of Reinforcing Particle Size in Tailoring Interfacial Microstructure and Wear Performance of Selective Laser Melting WC/Inconel 718 Composites

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Qimin Shi ◽  
Dongdong Gu ◽  
Kaijie Lin ◽  
Wenhua Chen ◽  
Mujian Xia ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Interfacial Microstructure ◽  
Interfacial Bonding ◽  
Wear Properties ◽  
Laser Melting ◽  
Metallurgical Bonding ◽  
The Matrix

In this paper, both traditional Inconel 718 parts and WC/Inconel 718 composites were fabricated by selective laser melting (SLM). The size of WC particles was observed to play a crucial role in determining the microstructural evolution, distortion, and microcracks around the WC particles, which inturn also affected the effective mechanical properties of WC/Inconel 718 composites. The use of the 5.25 μm diameter WC particles resulted in fine dendrites at the interface between the WC particle and the Inconel 718 matrix. This was attributed to the formation of an annular heat flow and radially arranged temperature gradient directions around the WC particle that increased the contact area between the matrix and the particle, thereby also improving the interfacial bonding. A sound metallurgical bonding at the interface was achieved with negligible distortion and microcracks due to a relatively uniform temperature distribution and temperature gradient (4.7 × 103 °C/mm) at the interface. This also explains the generation of dense and smooth interfacial bonding, which yielded a low average friction coefficient of 0.21. The wear properties were improved since grooves and spallation were reduced with the decrease of the WC size.

In Situ AFM Characterization of Deformation Behavior of Nano TiC Reinforced Inconel 718 Superalloy Prepared by Selective Laser Melting

2015 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Xinnan Wang ◽  
Yun Wang
Keyword(s):  
Selective Laser Melting ◽  
Inconel 718 ◽  
Sample Surface ◽  
Nano Particles ◽  
Image Correlation ◽  
Strain Condition ◽  
Laser Melting ◽  
Three Point Bending ◽  
The Matrix

Laser assisted additive manufacturing (LAAM) is regarded as a complementary method to traditional manufacturing processes and it has drawn significant attention from both industry and academia. Improving the performance of components fabricated by LAAM has been an important research task in recent years due to the inevitable negative effects introduced by in the LAAM process, such as porosity, inhomogeneity, and tensile residual stress. In this study, to obtain high-performance metal components by LAAM, nano-TiC particles are adopted to reinforce Inconel 718 and the mixed powders of TiC and Inconel 718 are processed by selective laser melting (SLM). To investigate the effect of TiC concentration on the property and performance of the metal matrix composite, samples with three levels of nano-TiC addition (0, 0.25, 0.5 wt.%) are prepared, in which the SLM process parameters are kept the same for all cases. Three-point bending tests are performed to determine the optimum nano TiC addition. It is found that the material of 0.5 wt.% TiC addition results in the highest bending modulus. Compared with pure Inconel 718, the composite with 0.5 wt.% nano-TiC shows 38% increase in flexural modulus. In addition, to better understand the reinforcing mechanism of nano TiC particles, the SLM processed samples are characterized using a self-designed micro/nano three-point bending tester that is incorporated with an atomic force microscope (AFM) to in situ observe the nanoparticles movement on the sample surface under loading. The sample surface is scanned by AFM at 0%, 2%, 4% and 6% strain condition during the test, and the migration of individual nano particles at the sample surface is tracked at each strain condition. The AFM observations show that the dispersion of TiC nanoparticles is overall random and uniform in the Inconel 718 matrix, and localized agglomeration of TiC particles exists. The interfaces between nanoparticles and the matrix are generally continuous and free of any deleterious micro cracks, indicating a favorable metallurgical bonding feature. The surface morphologies obtained by AFM at different strain conditions are processed by digital image correlation technique to obtain the strain fields during the deformation process. The results show that the agglomerated TiC particles serve as defects in the material, leading to relative sliding of particles with respect to the matrix. This is believed to be the main factor that limits the performance of the composites made by SLM.

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.

Properties of aluminum metal matrix composites manufactured by selective laser melting

2021 ◽  
Vol 112 (7) ◽  
pp. 552-564
Author(s):  
Christian Felber ◽  
Florian Rödl ◽  
Ferdinand Haider
Keyword(s):  
Additive Manufacturing ◽  
Aluminum Alloys ◽  
Selective Laser Melting ◽  
Metal Matrix ◽  
High Hardness ◽  
High Strength ◽  
Laser Melting ◽  
Scanning Calorimetry ◽  
Particle Reinforcement ◽  
The Matrix

Abstract The most promising metal processing additive manufacturing technique in industry is selective laser melting, but only a few alloys are commercially available, limiting the potential of this technique. In particular high strength aluminum alloys, which are of great importance in the automotive industry, are missing. An aluminum 2024 alloy, reinforced by Ti-6Al-4V and B4C particles, could be used as a high strength alternative for aluminum alloys. Heat treating can be used to improve the mechanical properties of the metal matrix composite. Dynamic scanning calorimetry shows the formation of Al2Cu precipitates in the matrix instead of the expected Al2CuMg phases due to the loss of magnesium during printing, and precipitation processes are accelerated due to particle reinforcement and additive manufacturing. Strong reactions between aluminum and Ti-6Al-4V are observed in the microstructure, while B4C shows no reaction with the matrix or the titanium. The material shows high hardness, high stiffness, and low ductility through precipitation and particle reinforcement.

scholarly journals Effect of the Solution Temperature on the Precipitates and Grain Evolution of IN718 Fabricated by Laser Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 340 ◽  
Author(s):  
Yu Cao ◽  
Pucun Bai ◽  
Fei Liu ◽  
Xiaohu Hou ◽  
Yuhao Guo
Keyword(s):  
Selective Laser Melting ◽  
Treatment Temperature ◽  
Solution Temperature ◽  
Recrystallization Process ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Laves Phases ◽  
The Matrix ◽  
In718 Superalloy ◽  
Recrystallized Grain Size

The effects of the solution heat treatment temperature on the precipitates, grain boundary evolution and response of the microhardness of Inconel 718 (IN718) superalloy fabricated by selective laser melting (SLM) were investigated. It was found that: (1) The long-chained Laves phases formed in the as-deposited condition dissolved into the matrix when the solution temperature rises above 980 °C. (2) The width-to-length ratio was maintained at approximately 1.6 when the solution was heated from 980 °C to 1080 °C, and dropped down to 1.03 when heated to 1130 °C. (3) Low-angle grain boundaries kept the same number fraction of 65% from 980 to 1080 °C as the as-deposited condition, and decreased dramatically from 1090 to 1130 °C to 4%. (4) Annealing twin boundaries occurred at 1090 °C with a number fraction of 3%, and quickly increased to 65% when heated to 1130 °C. It is concluded that the static recrystallization of IN718 fabricated by selective laser melting (SLM) occurred at 1090 °C and fast proceeded to full recrystallization at 1130 °C. The forming of annealing twins accompanies the recrystallization process and is an effective way to refine the recrystallized grain size.

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