Influence of Process Parameters on Microstructural Properties of L-DED Produced Ti64 Alloy

Abstract

Additive manufacturing (AM) techniques have revolutionized the manufacturing of complex and customized parts across various applications. However, they are known for producing titanium parts with high anisotropy and low ductility, due to high cooling gradient in the build direction and the presence of martensite phase in microstructure respectively. These are inherent problems which limit their application in critical engineering fields. Laser—Direct Energy Deposition (L-DED) produced parts also have the same disadvantages. Thus, the primary objective of this paper is to identify the optimal combination of process parameters for L-DED that can mitigate these inherent limitations. Keeping the parameters such as powder size, orientation angle and hatch angle as constant, the laser power and scan speed are varied to fabricate 9 different sets of samples using L-DED. The research methodology includes an analysis of the microstructure, focusing on grain width, phase distribution, lath characteristics and presence of defects, if any. Microscopy and XRD techniques were used to observe the microstructure. Additionally, hardness studies were performed to evaluate the changes in material hardness. It was noticed that laser power significantly influences β width and α’ length while scan speed has a lesser dominant effect on both of them. The findings will contribute to the development of process-structure-property relations for L-DED-produced Ti64 and further, optimized manufacturing strategies for producing titanium parts with reduced anisotropy and increased ductility. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.