Microstructure and mechanical properties of transition zone in laser additive manufacturing of TC4/AlSi12 bimetal structure

Abstract

Ti/Al bimetallic structure (BS) has a good development prospect and broader application potential in aerospace engineering. Considering the limitation that dissimilar welding is only applicable to the thin plate, it is necessary to explore a new manufacturing process for Ti/Al BS. In this study, a TC4/AlSi12 BS was prepared by laser additive manufacturing (LAM). TC4 zone, AlSi12 zone and transition zone were formed in the LAM process. Due to the sufficient diffusion reaction, the transition zone with a width of about 0.8mm was obtained. At the same time, a few micro-cracks were found in the transition zone. The microstructure and phase composition of the transition zone had been emphatically studied. Research results showed that the presence of Si element made the phase composition of the transition zone more complicated. The structure evolution from TC4 to AlSi12 was: α-Ti → Ti3Al → TiAl+(TiAl+Si) → Ti5Si3 → TiAl3+(α-Al+Si) → α-Al+ Si +TiAl3 +(α-Al+Si) → α-Al+Si+(α-Al+Si). The hardness distribution of BS was uneven, with the highest value reaching 524HV. The tensile strength of the TC4/AlSi12 BS was about 110Mpa, and the fracture location was located in the transition zone.

Laser Additive Manufacturing of TC4/AlSi12 Bimetallic Structure via Nb Interlayer

“…An AlSi12 cuboid of about 40 × 25 × 20 mm was then deposited on the Nb interlayer, and finally BS with a total size of about 40 × 25 × 40 mm was deposited, as shown in Figure 1a. The process parameters for samples 1 and 2 are shown in Table 2, which were obtained on the basis of extensive preliminary experiments [19]. The physical photos of the samples are shown in Figure 1c,d; compared with sample 1, the reduction of laser power during the deposition of AlSi12 in sample 2 leads to a significant alleviation of its collapse, resulting in a flatter and smoother surface and sides.…”

Mechanical performance and failure modes of self-piercing riveted joints between AA6061 and solution-treated TC4 alloy

“…To promote green and low-carbon development, lightweight has achieved wide development prospects in many industries, and lightweight is a key development direction in the future [1][2][3]. TC4 (Ti-6Al-4V) titanium alloy has high tensile strength, low density, and stable mechanical properties at high temperatures, which is widely used in the structure and fasteners of aircraft bodies [4,5]. Generally, aluminum alloy are the ideal materials for versatile applications.…”