Surface Integrity and Manufacturability of Post-processed Ti-5Al-5Mo-5V-3Cr Parts Fabricated via Additive Manufacturing

Abstract

Additive manufacturing (AM) technologies, particularly laser powder bed fusion (LPBF), are revolutionizing the production of complex geometric components. The Ti-5Al-5Mo-5V-3Cr (Ti-5553) alloy, a near-β titanium alloy, is renowned for its exceptional strength, toughness, and high strength-to-weight ratio, making it ideal for fabricating critical aircraft components using LPBF. Despite the advantages of AM, post-machining processes such as drilling are necessary to achieve the tight tolerances and smooth surface finishes required for critical parts. However, the unique machinability characteristics of AM-produced titanium parts present challenges compared to conventionally manufactured counterparts. Although the machinability of cast and wrought titanium alloys is well documented, limited knowledge exists regarding the machinability of AM-produced variants. In this research, Ti-5553 samples were fabricated using LPBF, followed by post-machining under varying drilling parameters. Surface integrity and manufacturability were assessed by characterizing the hole surface microstructure, chemical composition, defects, morphology, roughness, and microhardness, and by evaluating the cutting forces and cutting temperatures. This study demonstrates the manufacturability of LPBF-built Ti-5553 parts and reveals the influence of drilling parameters on surface integrity and manufacturability, providing valuable insights into optimizing machining processes for AM titanium parts and enhancing their use in critical aerospace applications.