The origin of abnormal grain growth upon thermomechanical processing of laser powder-bed fusion alloys

Materialia ◽  
2021 ◽  
pp. 101243
Author(s):  
Leonardo Shoji Aota ◽  
Priyanshu Bajaj ◽  
Kahl Dick Zilnyk ◽  
Dirk Ponge ◽  
Hugo Ricardo Zschommler Sandim
Keyword(s):  
Grain Growth ◽  
Thermomechanical Processing ◽  
Abnormal Grain Growth ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

Numerical Study of Grain Growth in Laser Powder Bed Fusion Additive Manufacturing of Metals

2021 ◽  
pp. 2141012
Author(s):  
Zhida Huang ◽  
Zongyue Fan ◽  
Hao Wang ◽  
Bo Li
Keyword(s):  
Heat Transfer ◽  
Additive Manufacturing ◽  
Grain Growth ◽  
Phase Field ◽  
Field Calculation ◽  
Computational Domain ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Cooling Process ◽  
Powder Bed

Laser Powder Bed Fusion (LPBF) is an additive manufacturing method that manufactures high density and quality metal products. We present a coupled grain growth and heat transfer modeling technique to understand the materials microstructure evolution in metals during the cooling process of LPBF. The phase-field model is combined with a transient heat transfer equation to simulate the solidification and crystallization of the melt pool simultaneously. Specifically, the variable domain and driving force of the order parameters in the phase-field calculation are defined using current temperature distribution. Additionally, the latent heat generated by crystallization is introduced as a heat source to affect temperature evolution in the cooling process. The finite element method with a staggering strategy is employed to solve the coupled governing equations on an irregular computational domain. The computational framework is verified in a one-dimensional solidification problem by comparing the velocity of the fluid-solid interface. The two-way coupling solution of solidification and crystallization is studied in an example of LPBF of Aluminum alloys.

Grain Growth During Keyhole Mode Pulsed Laser Powder Bed Fusion of IN738LC

JOM ◽  
2020 ◽  
Vol 72 (3) ◽  
pp. 1074-1084
Author(s):  
Z. W. Chen ◽  
T. Guraya ◽  
S. Singamneni ◽  
M. A. L. Phan
Keyword(s):  
Grain Growth ◽  
Pulsed Laser ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

scholarly journals Microstructure and Hardness Evolution of Solution Annealed Inconel 625/TiC Composite Processed by Laser Powder Bed Fusion

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 929
Author(s):  
Giulio Marchese ◽  
Alberta Aversa ◽  
Emilio Bassini
Keyword(s):  
Grain Growth ◽  
Inconel 625 ◽  
Powder Bed Fusion ◽  
Solution Annealing ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Microstructure Stability ◽  
Columnar Grains ◽  
Equiaxed Grains ◽  
Intensive Formation

This study deals with the Inconel 625 (IN625) alloy reinforced with micro-TiC particles processed by laser powder bed fusion. The microstructure and hardness in the as-built and solution-annealed states were investigated. The microstructures of the as-built IN625 and IN625/TiC states were primarily made up of columnar grains along the building direction. After the solution annealing at 1150 °C for 2 h, the IN625 alloy consisted of equiaxed grains due to recrystallization and grain growth. On the contrary, the solution-annealed IN625/TiC composite still presented columnar grains. Therefore, the TiC particles hinder the recrystallization, indicating higher microstructure stability for the composite. For the IN625/TiC composite, both the reduced alteration of the grains and the more intensive formation of carbides prevent a remarkable hardness reduction in the solution-annealed state.

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.

Heat source model calibration for thermal analysis of laser powder-bed fusion

2020 ◽  
Vol 106 (7-8) ◽  
pp. 3367-3379 ◽  
Author(s):  
Shahriar Imani Shahabad ◽  
Zhidong Zhang ◽  
Ali Keshavarzkermani ◽  
Usman Ali ◽  
Yahya Mahmoodkhani ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Heat Source ◽  
Model Calibration ◽  
Source Model ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Heat Source Model ◽  
Powder Bed

scholarly journals The Effect of Cu Content and Surface Finish on the Metal Dusting Resistance of Additively Manufactured NiCu Alloys

2021 ◽  
Author(s):  
Katrin Jahns ◽  
Anke S. Ulrich ◽  
Clara Schlereth ◽  
Lukas Reiff ◽  
Ulrich Krupp ◽  
...  
Keyword(s):  
Surface Finish ◽  
Powder Bed Fusion ◽  
Metal Dusting ◽  
Laser Powder Bed Fusion ◽  
Roughness Measurement ◽  
Powder Bed ◽  
Cu Content ◽  
Binary Model ◽  
Interesting Candidate ◽  
Nicu Alloys

AbstractDue to the inhibiting behavior of Cu, NiCu alloys represent an interesting candidate in carburizing atmospheres. However, manufacturing by conventional casting is limited. It is important to know whether the corrosion behavior of conventionally and additively manufactured parts differ. Samples of binary NiCu alloys and Monel Alloy 400 were generated by laser powder bed fusion (LPBF) and exposed to a carburizing atmosphere (20 vol% CO–20% H2–1% H2O–8% CO2–51% Ar) at 620 °C and 18 bar for 960 h. Powders and printed samples were investigated using several analytic techniques such as EPMA, SEM, and roughness measurement. Grinding of the material after building (P1200 grit surface finish) generally reduced the metal dusting attack. Comparing the different compositions, a much lower attack was found in the case of the binary model alloys, whereas the technical Monel Alloy 400 showed a four orders of magnitude higher mass loss during exposure despite its Cu content of more than 30 wt%.

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