Effects of Electropolishing on Mechanical Properties and Bio-Corrosion of Ti6Al4V Fabricated by Electron Beam Melting Additive Manufacturing.

Yao-Cheng Wu,Jacob C Huang,Chee-How Ng,Yueh-Chun Chung,Che-Nan Kuo

doi:10.3390/ma12091466

Abstract

Electron beam melting (EBM) has become one of the most promising additive manufacturing (AM) technologies. However, EBM tends to result in products with rougher surfaces due to the melt pool which causes adjacent powder particles to be sintered to the surface without being melted. Hence, it is necessary to improve the surface quality by post processing. The current study evaluates the tensile response of Ti6Al4V EBMed samples subject to various electropolishing (EP) treatments. The surface roughness Ra readings can be improved from over 24 µm down to about 4.5 µm by proper EP, resulting in apparent tensile elongation improvement from 7.6% to 11.6%, or a tensile plasticity increment of 53%, without any loss of elastic modulus or tensile strength. Moreover, the in-vitro bio-corrosion test in simulating body fluid (SBF) of the as-EBMed and EP-processed samples is also conducted. The potentiodynamic polarization reveals that the bio-corrosion resistance is improved by the lower Ra through proper EP treatments. This is due to the formation of a denser and more completely passivated oxide layer with less defects after proper EP duration. But when the EBMed samples are over-electropolished, nano pitting would induce a degraded bio-corrosion performance.

Highlights

Additive manufacturing (AM), known as three-dimensional printing (3-D printing), is a technology which is used to fabricate objects directly from a 3D model and print layers by layers [1,2].Each layer is a cross-section of the work piece derived from the Computer Aided Design (CAD) data.it can be classified into many types depending on what materials are used, how the layers are built, and how the layers are bonded to each other
Electron beam melting (EBM), one kind of powder bed fusion (PBF) technology, is conceptualized and patented by Arcam AB® based in Sweden [4]
The additive manufacturing (AM) EBM process was conducted by Arcam Q10 system which developed as theas3rd

Summary

Introduction

Each layer is a cross-section of the work piece derived from the Computer Aided Design (CAD) data. It can be classified into many types depending on what materials are used, how the layers are built, and how the layers are bonded to each other. These major differences will influence mechanical properties and the accuracy between the CAD models and final products. Electron beam melting (EBM), one kind of PBF technology, is conceptualized and patented by Arcam AB® based in Sweden [4]. The process uses the electron beam to melt metal powders in a vacuum chamber [5]

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Conclusion