Development of Build Strategies for Thin Walled Ti6al4v Components Using Laser Powder Bed Fusion Process

Abstract

Complex thin-walled components find Numerous applications in aerospace, automotive and marine domains to meet the demands in design, manufacturing, durability, reliability, fuel efficiency and sustainability due to their superior properties. Although thin-walled components offer several advantages, their manufacturing presents significant challenges, especially when it comes to achieve the required geometric characteristics, uniform distribution of tolerances, surface integrity, consistency and accuracy. Laser Powder Bed Fusion (LPBF) has created interest across the industries, in particular, aerospace sectors to produce metallic components with complex geometries directly from the CAD model. In LPBF process, a thin layer of material is selectively melted and solidified, resulting in the creation of a dense and precise geometric structure. However, the rapid heating and cooling cycles in this process result in a high temperature gradient, leading to thermal distortions. These distortions, in turn, cause dimensional inaccuracies and significant variation in the mechanical performance of the parts. Therefore, the present work is focused on the development of a systematic approach based on the inherent strain method, viz. Ansys Additive Print (AAP) software to predict the residual stresses and thermal distortion induced in thin-walled Ti6Al4V components and to improve the quality of parts produced in LPBF. During the development of the work, a single cantilever beam was initially considered. Subsequently, the study was extended to the aero-engine compressor blade, as these components are the suitable representation of thin-walled parts. The process parameters, such as laser power, scan speed, and hatch distance, were varied extensively in this study. It can be noted that upto 20 % deviation in residual stress and 10% deviation in maximum distortion were obtained between numerical and the experimental results. Additionally, it was found that the use of low energy density for fabricating the thin-walled components in