Effect of scanning strategy on microstructure and properties of titanium-aluminum heterogeneous alloy fabricated by additive manufacturing
The titanium-aluminum heterogeneous alloy composite structures with significant differences in physical properties fabricated by laser melting deposition is of great significance for expanding the application scope of high specific strength titanium-aluminum composite structures in major aviation equipment. In this paper,the AlTiVNbSi high entropy alloy was used as the intermediate transition layer,and the Ti-Al heterogeneous alloy integrated composite structure was prepared by laser melting deposition technology. Based on metallographic microscope (OM),scanning electron microscope (SEM),micro-hardness,room temperature tensile testing and other detection methods,the effects of scanning strategy on the microstructure and mechanical properties of Ti-Al heterojunction interface region were studied. The results indicate that optimizing the scanning strategy can significantly improve the bonding situation of heterogeneous interface regions. Compared with the ribbon scanning strategy,the microstructure obtained under the ring scanning strategy is smaller,dense,and the grain growth direction is varied. The interface layer thickness obtained under the ring scanning strategy is about 10 μm,which is 50％ thinner than that obtained under the ribbon scanning strategy. At the same time,the tensile strength of the interface bonding zone obtained under the ring scanning strategy has also been significantly improved,with a maximum tensile strength of about 235 MPa. The fracture location of the tensile specimen occurs at the interface between the titanium alloy and the high entropy alloy.
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