Microstructure effects on the machinability behaviour of Ti6Al4V produced by Selective Laser Melting and Electron Beam Melting process

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:823

Article

Milton, Samuel^1,3  Rigo, Olivier³  LeCorre, Sebastien⁴  Morandeau, Antoine²  Siriki, Raveendra⁵  Bocher, Philippe⁴  Leroy, Rene¹ 

[1] Univ Tours, Lab Mecan Gabriel Lame, Polytech Tours, Tours, France

[2] R&D, Sandv Tooling Div Coromant, Fondettes, France

[3] Sirris, Diepenbeek, Belgium

[4] Univ Quebec, Ecole Technol Super, Montreal, PQ, Canada

[5] AB Sandvik Mat Technol, Sandviken, Sweden

关键词: Electron beam melting (EBM);    Selective laser melting (SLM);    Microstructure;    Texture;    Milling;    Ti6Al4V;   

DOI  :  10.1016/j.msea.2021.141773

来源: Elsevier

【 摘 要 】

Additive Manufacturing (AM) is gaining widespread attention over the last decade in the areas of product development and prototyping, across aerospace and medical domains. Nevertheless, the built parts are near-net shaped that usually require a machining finish to improve the surface quality and operational life. The current study aims to document the machinability behaviour of the Ti6Al4V parts fabricated by the AM process, which is based on powder bed fusion, namely, Selective Laser Melting (SLM) and Electron Beam Melting (EBM). Further, machinability parameters are correlated with the microstructure and mechanical properties of the material. Face milling operation is performed under finishing conditions to study the response on the cutting forces. The effect of Hot Isostatic Pressing (HIP) and the influence of the build direction on microstructure and machinability have been investigated for the two AM processes. The effect of crystallographic textures and microstructure morphology of alpha and reconstructed prior 13 phases on the mechanical properties was studied using shear tests. It was observed that the SLM process primarily produced homogenous and fine alpha lath structures with less grain boundary alpha (alpha GB) grains, leading to low shear resistance and hence generated low cutting forces. On the other hand, the EBM process produced microstructures with variable morphologies, including more grain boundary alpha (alpha GB) grains and widmenstatten structures which resulted in a higher shear resistance and forces. The results show a striking influence of the microstructure induced by the type of the AM process, build orientation, and the subsequent heat treatment on the shear resistance and their ability to be machined. Further, the crystallographic textures were not strong for both processes and seem not to impact the machining process. The results highlight a strong process - property link which demands optimization of the cutting process for the type of the AM process and the resulting microstructure.

【 授权许可】

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