Microstructural modification of Ti–6Al–4V by using an in-situ printed heat sink in Electron Beam Melting® (EBM)

Abstract

Please cite this article as: Jamshidinia, M., Atabaki, M.M., Zahiri, M., Kelly, S., Sadek, A., Kovacevic, R.,Microstructural Modification of Ti-6Al-4<ce:hsp sp=0.25/>V by Using an In-Situ Printed Heat Sink in Electron Abstract Unidirectional heat transfer during additive manufacturing (AM) processes results in anisotropy of microstructure and mechanical properties in fabricated components. In the present study, the influence of in-situ printed heat sinks on the microstructure of Ti-6Al-4V was investigated. Different numbers of heat sinks were designed and produced by the Electron Beam Melting® (EBM) process. The coupons were characterized by an optical microscope, scanning electron microscope, tensile and hardness tests, and fracture analysis. An increase in the number of heat sinks was accompanied by a reduction in grain thickness. While elongated grains still formed in all coupons, due to the dominant heat transfer along the buildup direction. The refinement of microstructure was confirmed by a reduction in the average thickness of α-lath from 1.73 μm in the coupon with no heat sink to 1.01 μm in the coupon with the highest number of the heat sinks. The ultimate tensile strength and hardness were increased by increasing the number of heat sinks. The results of fractorgraphy suggested that coupons with the maximum number of heat sinks (5-HS) showed a more ductile fracture. Also, digital reconstruction of the fracture surface showed that the unmelted powder particles had an influence on the crack initiation.

Effects of heat treatments on microstructure and properties of Ti-6Al-4V ELI alloy fabricated by electron beam melting (EBM)

“…In this study, α lath thickness was considered as the relevant microstructural characteristic dimension, following a previous work where Hall-Petch equation was proposed for lamellar structured steels [43]. A Hall-Petch type equation was previously suggested for hardness and yield strength of EBM Ti-6Al-4V by Jamshidinia et al [44]. The empirical relation between α lath thickness and hardness values obtained in this study, as well as values shown by other authors [12], Figure 17, was modeled with the following equation:…”

The Hardness of Additively Manufactured Alloys

“…Vickers micro-hardness as a function of alpha lath width for Ti-6Al-4V fabricated by AM from [54,152,174,175,176,177,178,179]. Error bars, where available, represent the standard deviation in measurements.…”

Recent Progress in Biomimetic Additive Manufacturing Technology: From Materials to Functional Structures

“…Other ways to distinguish these technologies are to group them by the physical state of raw materials (i.e., liquid, solid, or powder form) and by the methods that are used to fuse the raw materials together (e.g., thermal, ultraviolet (UV) light, laser, or electron beam) . A number of mature AM technologies have been successfully commercialized such as fused deposition modeling (FDM), direct ink writing (DIW), selective laser sintering, stereolithography (SLA), powder bed inkjet 3D printing (inkjet 3D), two‐photon polymerization, laminated object manufacturing, and their variants such as multijet printing (MJP) and selective laser melting (Figure ). However, how well can these AM processes be used in fabricating biomimetic materials and structures and what is the current status of AM technology development to address the fabrication challenges of biomimetic materials and structures?…”