Influences of the process parameter and thermal cycles on the quality of 308L stainless steel walls produced by additive manufacturing utilizing an arc welding source

The processing window for laser powder bed fusion (LPBF) of A20X aluminum alloy was determined to increase the build rate and reduce the fabrication cost for this material. The influence of hatch spacing, laser scan speed, and powder layer thickness on the microstructure and mechanical properties were also systematically investigated. Over a wide processing window (40–115 J/mm3 energy density), near fully dense and crack-free components were achieved. In all cases, the as-built microstructure consisted of an aluminum matrix with TiB2 particles and Al2Cu precipitates, where volume fraction and size of both TiB2 and Al2Cu phases were found to be independent of the LPBF process parameters. A fine equiaxed grain structure with a random crystallographic orientation was observed in the vertical section (XZ-plane) of the as-built samples. This led to an isotropic elastic modulus, ultimate tensile strength, and total elongation. The yield strength, however, was found to be anisotropic, exhibiting a 16 % difference for different orientations. The average grain size decreased 54 % due to increased scan speed and reduced powder layer thickness. This resulted in a remarkable improvement in the alloy micro-hardness value from 108 HV to 124 HV, where the experimental data obeyed the Hall-Petch relationship. 

Processability and characterization of A20X aluminum alloy fabricated by laser powder bed fusion

Evaluation of Microstructure, Residual Stress, and Mechanical Properties in Different Planes of Wire + Arc Additive Manufactured Nickel-Based Superalloy

Single-track study of A20X aluminum alloy fabricated by laser powder bed fusion: Modeling and experiments

Failure analysis of gas and wind turbine blades: A review

In-process failure analysis of thin-wall structures made by laser powder bed fusion additive manufacturing

Wire plus arc additive manufacturing (WAAM) technology is utilized to fabricate a 347 stainless steel (SS347) plate using the gas metal arc welding process. The tensile properties of the WAAM plate revealed enhanced strength in comparison with the wrought alloy SS347. The microhardness and the ferrite measurement along the building direction (BD) were in the range of 265–226 HV0.5 and 2.2–5.1 FN (Ferrite number), respectively. The microstructural features were comprehensively examined using electron backscatter diffraction (EBSD) analysis and the Inverse pole figure (IPF) maps revealed a strong texture along the BD. Also, well-aligned equiaxed and columnar dendrites with a lower fraction of niobium carbide (NbC) was noticed in the microstructures of the as-built WAAM plate. A three-dimensional finite element model was developed to simulate the build-up of a WAAM plate. Goldak heat source is used to model heat flux in thermal analysis, and the temperature distributions were predicted. Further, residual stress and plastic strain distributions were examined at various stages of the WAAM process.

Fabrication of Gas Metal Arc Welding Based Wire Plus Arc Additive Manufactured 347 Stainless Steel Structure: Behavioral Analysis Through Experimentation and Finite Element Method

This is the first of two manuscripts that presents a computationally efficient full-field deterministic model for laser powder bed fusion (LPBF). A new hybrid line (HL) heat input model integrates an exponentially decaying (ED) heat input over a portion of a laser path to significantly reduce the computational time. Experimentally measured properties of the high gamma prime nickel-based superalloy RENE 65 are implemented in the model to predict the in-process temperature distribution, stresses, and distortions. The model accounts for specific properties of the material as different phases. The first manuscript presents the HL heat transfer model, which is compared with the beam-scale ED model, along with the melt pool geometry obtained experimentally by varying the laser parameters. The predicted melt pool geometry of the beam-scale ED model is shown to have good agreement with experimental measurements. While the proposed HL model exhibits lesser accuracy in predicting the melt pool geometries, it can predict the cooling rates and nodal temperatures as accurately as to the ED model. Moreover, under large time integration steps, the HL model becomes more than 1500 times faster than the ED model.

Reza Tangestani

Papers

In-process failure analysis of thin-wall structures made by laser powder bed fusion additive manufacturing

Fabrication of Gas Metal Arc Welding Based Wire Plus Arc Additive Manufactured 347 Stainless Steel Structure: Behavioral Analysis Through Experimentation and Finite Element Method

An Efficient Track-Scale Model for Laser Powder Bed Fusion Additive Manufacturing: Part 2—Mechanical Model