Investigation on surface integrity of electron beam melted Ti-6Al-4V by precision grinding and elect

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Electron beam melting (EBM),as an excellent Additive Manufacturing (AM) technol-ogy,enables the printing of Ti-6Al-4V alloy for a wide range of applications such as aerospace and biomechanical industries.It improves functionality and integrity of components and negates complexities in assembly processes.However,due to the poor surface and sub-surface integrity rep-resented by the rough surface finish and low dimensional accuracy,achieving a favorable surface condition is quite challenging.Therefore,post processing becomes essential for these electron beam melted (EBM-ed) Ti-6Al-4V alloys.Being the most common technique to improve such parts,milling of Ti-6Al-4V alloy is very challenging and resulting tool wear issues,due to its unique mate-rial properties.Thus,this paper presents a comprehensive study on the surface integrity of EBM-ed Ti-6Al-4V parts processed by precision grinding and electropolishing,aiming to qualitatively and quantitatively clarify the interrelation between process parameters and processed surface quality.The surface and subsurface characteristics such as profile accuracy,surface roughness,microstruc-ture,defective layer and residual stress before and after post processing were compared and evalu-ated.The results show that by precision grinding,the profile accuracy was improved from over 300 μm PV to 7 μm PV,while surface roughness (Ra) was reduced from 30 μm to about 2 μm.The layer with partially melt particles was removed,but introduced a deformed subsurface layer with more residual stress.Then by applying electropolishing,the residual stress was released and the deformed layer was removed.In addition,Ra was further reduced to 0.65 μm.The research can serve as a reference for the integration of post machining processes with AM.
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