Microstructural evolution and phase transformation of Inconel 718 alloys fabricated by selective laser melting under different heat treatment

2019 ◽  
Vol 39 ◽  
pp. 226-232 ◽  
Author(s):  
Peng Liu ◽  
Jiaying Hu ◽  
Siyu Sun ◽  
Keyun Feng ◽  
Yuanbin Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Selective Laser Melting ◽  
Microstructural Evolution ◽  
Inconel 718 ◽  
Laser Melting

Microstructural Evolution and Phase Transformation on the X-Y Surface of Inconel 718 Ni-Based Alloys Fabricated by Selective Laser Melting under Different Heat Treatment

2019 ◽  
Vol 38 (2019) ◽  
pp. 229-236
Author(s):  
Peng Liu ◽  
Siyu Sun ◽  
Meiqing Cao ◽  
Jianhong Gong ◽  
Jiaying Hu
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Phase Transformation ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Solution Process ◽  
Surface Hardness ◽  
Solution Temperature ◽  
Air Cooling ◽  
Laser Melting

AbstractMicrostructure, hardness, precipitates and phase transformation on the X-Y surface of Inconel 718 Ni-based alloys fabricated by selective laser melting (SLM) were studied before and after a suitable heat treatment. The test results show that the obvious weld beads structure was observed on the surface of the as-built alloys, and the microstructure shows seriously inhomogeneous with distributing columnar crystals and fine dendrites. When the 720°C, 3 h/furnace cooling+620°C and 3 h/air cooling was used, the columnar and small dendritic crystals begun to transform into bulk crystals, and the weld beads structure disappeared instantly. The X-Y surface hardness of alloys is about HV490-540, which is higher than the one of other heat treatment processes. With the increase of solid solution temperature, the microstructure on the surface of alloys shows an obvious refining characterization. The hardness value on the surface was also reduced gradually. The typical columnar crystals, dendrites, intermetallic compounds and precipitated hardening phase (Cr-Fe-Mo-Ni, FeNi and Ni8Nb) were also reduced or could not be found. Under the solid solution process of 950°C, the fine homogeneous δ phase and γ′ phase in the grain or near the grain boundary had an important effect on the suitable surface hardness value (HV476-500) of alloys.

Effect of heat treatment on the phase transformation and mechanical properties of Ti6Al4V fabricated by selective laser melting

2018 ◽  
Vol 764 ◽  
pp. 1056-1071 ◽  
Author(s):  
Xingchen Yan ◽  
Shuo Yin ◽  
Chaoyue Chen ◽  
Chunjie Huang ◽  
Rodolphe Bolot ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Transformation ◽  
Selective Laser Melting ◽  
Laser Melting

scholarly journals The effect of texture on the low cycle fatigue property of Inconel 718 by selective laser melting

2018 ◽  
Vol 165 ◽  
pp. 02007 ◽  
Author(s):  
Zhongjiao Zhou ◽  
Xu Hua ◽  
Changpeng Li ◽  
Guofeng Chen
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Low Cycle Fatigue ◽  
Added Value ◽  
Cycle Fatigue ◽  
Laser Melting ◽  
Safety Critical ◽  
The Impact

In recent decades, additive manufacturing (AM) technology has shown its great advantages to produce end-use products with complex design and high-added value. However, the AM-specific characters, such as inherent material anomalies (porosity, lack of fusion defects, or inclusions), anisotropy, location-specific properties and residual stresses, prevent AM from widely adoption in safety-critical parts. Therefore, the damage tolerance assessment of AM parts is desperately necessary. In this study, the impact of residual stress and the induced texture (columnar/equiax grain structure) after different heat treatment on the low cycle fatigue (LCF) behavior of Inconel 718 fabricated through selective laser melting (SLM) is investigated. The results showed that the texture of AMed parts can be controlled by suitable heat treatment, based on the residual stress during AM processing acting as the drive force to recrystallization. For SLMed Inconel 718 samples with columnar grains, anisotropic LCF properties exist, while no obvious sensitivity to orientations is shown for samples with equiaxed grains. This work is significantly meaningful to speed up the design-to-product transformation of safety-critical AM parts and optimize the orientation of components for various applications.

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