scholarly journals Numerical Alloy Development for Additive Manufacturing towards Reduced Cracking Susceptibility

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 902
Author(s):  
Benjamin Wahlmann ◽  
Dominik Leidel ◽  
Matthias Markl ◽  
Carolin Körner
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Electron Beam Melting ◽  
Volume Fraction ◽  
Crack Model ◽  
Alloy Development ◽  
Cracking Behavior ◽  
Dsc Measurements ◽  
Solidification Cracks ◽  
Nickel Base

In this work, we investigated the viability of established hot cracking models for numerically based development of crack-resistant nickel-base superalloys with a high γ′ volume fraction for additive manufacturing. Four cracking models were implemented, and one alloy designed for reduced cracking susceptibility was deduced based on each cracking criterion. The criteria were modeled using CALPHAD-based Scheil calculations. The alloys were designed using a previously developed multi-criteria optimization tool. The commercial superalloy Mar-M247 was chosen as the reference material. The alloys were fabricated by arc melting, then remelted with laser and electron beam, and the cracking was assessed. After electron beam melting, solidification cracks were more prevalent than cold cracks, and vice versa. The alloys exhibited vastly different crack densities ranging from 0 to nearly 12 mm−1. DSC measurements showed good qualitative agreement with the calculated transition temperatures. It was found that the cracking mechanisms differed strongly depending on the process temperature. A correlation analysis of the measured crack densities and the modeled cracking susceptibilities showed no clear positive correlation for any crack model, indicating that none of these models alone is sufficient to describe the cracking behavior of the alloys. One experimental alloy showed an improved cracking resistance during electron beam melting, suggesting that further development of the optimization-based alloy design approach could lead to the discovery of new crack-resistant superalloys.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

Microgeometry of the surface of electron beam additive manufacturing products. Selective electron beam melting

2021 ◽  
pp. 408-418
Author(s):  
E.V. Krasnova ◽  
Yu.A. Morgunov ◽  
B.P. Saushkin
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Physical Model ◽  
Electron Beam Melting ◽  
Metallurgical Process ◽  
Additive Technology ◽  
Selective Electron Beam Melting ◽  
Surface Microgeometry ◽  
Microstructure Of The Material

The results of the analysis of works related to the formation of surface microgeometry in the process of selective electron-beam melting are presented, and the physical model of this process is refined. The developing additive technology of selective electron-beam alloying and the directions in which its research is carried out, in particular, the analysis of the metallurgical process, the formation of the microstructure of the material, the formation of microstructure defects, are described. The roughness of the surface of products obtained by the SEBM technology, as well as the microgeometry of surfaces and the mechanisms of its formation, depending on various parameters of the process, are considered.

Ti6Al4V Parts Produced by Electron Beam Melting: Analysis of Dimensional Accuracy and Surface Roughness

2020 ◽  
Vol 19 (01) ◽  
pp. 107-130 ◽  
Author(s):  
R. Borrelli ◽  
S. Franchitti ◽  
C. Pirozzi ◽  
L. Carrino ◽  
L. Nele ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Electron Beam Melting ◽  
Complex Shape ◽  
Electron Beam Welding ◽  
Raw Materials ◽  
Dimensional Accuracy ◽  
High Energy ◽  
Quality Certification

Additive manufacturing (AM), applied to metal industry, is a family of processes that allows complex shape components to be realized from raw materials in the form of powders. Electron beam melting (EBM) is a relatively new additive manufacturing (AM) technology. Similar to electron-beam welding, EBM utilizes a high-energy electron beam as a moving heat source to melt metal powder, and 3D parts are produced in a layer-building fashion by rapid self-cooling. By EBM, it is possible to realize metallic complex shape components, e.g. fine network structures, internal cavities and channels, which are difficult to make by conventional manufacturing means. This feature is of particular interest in titanium industry in which numerous efforts are done to develop near net shape processes. In the field of mechanical engineering and, in particular, in the aerospace industry, it is crucial for quality certification purpose that components are produced through qualified and robust manufacturing processes ensuring high product repeatability. The contribution of the present work is to experimentally identify the EBM job parameters (sample orientation, location of the sample in the layer and height in the build chamber) that influence the dimensional accuracy and the surface roughness of the manufactured parts in Ti6Al4V. The repeatability of EBM is investigated too.

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