Machining Finish of Titanium Alloy Prepared by Additive Manufacturing

Abstract

Surface finish plays a critical role in functional performance of machined components. This study investigates machining finish of Ti-6Al-4V alloy prepared by Additive Manufacturing (AM) with a series of slot-milling experiments. The study compares the machined AMed part with that made of the conventional wrought Ti-6Al-4V. The microstructure of AMed parts is acicular α and Widmanstatten α lath structures compared to lamellar α structure of that in the wrought parts. Due to the unique microstructure from AM process, the AMed parts present higher strength and lower ductility. Therefore, a lower surface roughness is obtained in the milling of AMed parts compared to its counterpart of wrought parts. In addition, the machined surface of AMed parts possesses a topography of discontinued ridges. It is believed that the topography is due to low ductility of AMed part. The results show that the machined AMed part presents better surface finish. The study provides a guidance to optimization of machining parameters for AMed Ti-6Al-4V alloys.