Grain Refinement of Fe-X Alloys Fabricated by Laser Powder Bed Fusion

2021 ◽  
Vol 1016 ◽  
pp. 580-586
Author(s):  
Hideaki Ikehata ◽  
Eric Jägle
Keyword(s):  
Grain Refinement ◽  
Lattice Misfit ◽  
Average Diameter ◽  
Ferrite Matrix ◽  
Coarse Grained ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Iron Oxide Particles ◽  
Powder Bed ◽  
Ti Alloys

Grain refinement tendency of pure Fe and Fe-X (X=5~10at%Al, 2~10at%Ti) alloys produced by laser powder bed fusion (LPBF) process was investigated. Pure Fe, Al, and Ti powders were dry mixed and cubic samples were built from the mixtures. The microstructure analysis revealed that (1) the microstructure of pure Fe consisted of equiaxed grains having an average diameter of 1.7 μm with fine iron oxide particles. (2) Fe-5 and 10at%Al alloys showed coarse columnar grains. (3) Fe-2at%Ti shows a mixture of fine equiaxed and columnar shape grains. (4) the microstructures of Fe-5at%Ti and 10at%Ti alloys are fully equiaxed, and grain refinement tendency was confirmed with increasing Ti content. Ti(N,O) oxi-nitrides are efficient in reducing the grain size because of the low lattice misfit with the ferrite matrix. Additionally, the effectiveness of Ti(N,O) particles as grain refiners was confirmed by building samples using TiN powder mixed with Fe-10at%Al and Fe-2at%Ti. While these alloys alone are coarse grained, a dispersion of Ti(N,O) particles achieved a fine-grained microstructure.

scholarly journals Grain refinement in laser powder bed fusion: The influence of dynamic recrystallization and recovery

2020 ◽  
Vol 196 ◽  
pp. 109181
Author(s):  
Hossein Eskandari Sabzi ◽  
Nesma T. Aboulkhair ◽  
Xingzhong Liang ◽  
Xiao-Hui Li ◽  
Marco Simonelli ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

An investigation into the effect of process parameters on melt pool geometry, cell spacing, and grain refinement during laser powder bed fusion

2019 ◽  
Vol 116 ◽  
pp. 83-91 ◽  
Author(s):  
Ali Keshavarzkermani ◽  
Ehsan Marzbanrad ◽  
Reza Esmaeilizadeh ◽  
Yahya Mahmoodkhani ◽  
Usman Ali ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Process Parameters ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Melt Pool ◽  
Cell Spacing

Fabrication of Integrated Ni-Ti Alloys Possessing Both Super-elastic and Shape Memory Properties by Laser Powder Bed Fusion

2021 ◽  
Author(s):  
Jianran Lv ◽  
Hongyao Shen ◽  
Jianzhong Fu
Keyword(s):  
Shape Memory ◽  
Metallographic Analysis ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Scanning Calorimetry ◽  
Powder Bed ◽  
X Ray ◽  
High Relative Density ◽  
Ti Alloys ◽  
Shape Memory Effects

Abstract Purpose: Integrated Ni-Ti alloys possessing both super-elastic (SE) properties and shape memory effects (SMEs) greatly increase the flexibility of designing complex systems and have broad application prospects. However, existing research mainly focuses on connecting ready-made SE parts and SME parts though welding. Method: In this paper, laser powder bed fusion (LPBF) was used to fabricate integrated Ni-Ti alloys. First, SE parts with high relative density were fabricated with a Ni-rich powder. Then, different process parameters were used to fabricate the SME parts with a Ti-rich powder based on the SE parts. The integrated component with the best mechanical properties herein was selected. Metallographic analysis, energy dispersive X-ray spectroscopy, differential scanning calorimetry and micro-hardness analyses were carried out for this sample. Findings: The results show that the integrated component possessed both SE and SME properties at room temperature. Moreover, at the junction of the two materials, the grains were continuous and complete, which indicates that the joint had good quality. Originality: Our work confirms that LPBF is a feasible method to fabricate integrated Ni-Ti alloys possessing both SE and SME properties.

scholarly journals Unravelling the multi-scale structure–property relationship of laser powder bed fusion processed and heat-treated AlSi10Mg

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Van Cauwenbergh ◽  
V. Samaee ◽  
L. Thijs ◽  
J. Nejezchlebová ◽  
P. Sedlák ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Refinement ◽  
Rapid Solidification ◽  
Material Properties ◽  
Mechanical And Thermal Properties ◽  
Powder Bed Fusion ◽  
Structure Property ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Heat Treated

AbstractTailoring heat treatments for Laser Powder Bed Fusion (LPBF) processed materials is critical to ensure superior and repeatable material properties for high-end applications. This tailoring requires in-depth understanding of the LPBF-processed material. Therefore, the current study aims at unravelling the threefold interrelationship between the process (LPBF and heat treatment), the microstructure at different scales (macro-, meso-, micro-, and nano-scale), and the macroscopic material properties of AlSi10Mg. A similar solidification trajectory applies at different length scales when comparing the solidification of AlSi10Mg, ranging from mould-casting to rapid solidification (LPBF). The similarity in solidification trajectories triggers the reason why the Brody-Flemings cellular microsegregation solidification model could predict the cellular morphology of the LPBF as-printed microstructure. Where rapid solidification occurs at a much finer scale, the LPBF microstructure exhibits a significant grain refinement and a high degree of silicon (Si) supersaturation. This study has identified the grain refinement and Si supersaturation as critical assets of the as-printed microstructure, playing a vital role in achieving superior mechanical and thermal properties during heat treatment. Next, an electrical conductivity model could accurately predict the Si solute concentration in LPBF-processed and heat-treated AlSi10Mg and allows understanding the microstructural evolution during heat treatment. The LPBF-processed and heat-treated AlSi10Mg conditions (as-built (AB), direct-aged (DA), stress-relieved (SR), preheated (PH)) show an interesting range of superior mechanical properties (tensile strength: 300–450 MPa, elongation: 4–13%) compared to the mould-cast T6 reference condition.

scholarly journals On the Relevance of Volumetric Energy Density in the Investigation of Inconel 718 Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 538 ◽  
Author(s):  
Fabrizia Caiazzo ◽  
Vittorio Alfieri ◽  
Giuseppe Casalino
Keyword(s):  
Surface Roughness ◽  
Energy Density ◽  
Process Parameters ◽  
Vickers Hardness ◽  
Powder Bed Fusion ◽  
Processing Conditions ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Fractional Density ◽  
Experimental Variation

Laser powder bed fusion (LPBF) can fabricate products with tailored mechanical and surface properties. In fact, surface texture, roughness, pore size, the resulting fractional density, and microhardness highly depend on the processing conditions, which are very difficult to deal with. Therefore, this paper aims at investigating the relevance of the volumetric energy density (VED) that is a concise index of some governing factors with a potential operational use. This paper proves the fact that the observed experimental variation in the surface roughness, number and size of pores, the fractional density, and Vickers hardness can be explained in terms of VED that can help the investigator in dealing with several process parameters at once.

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