Formation of Ti2AlN and TiB and its effect on mechanical properties of Ti46Al4Nb1Mo alloy by adding BN particles

Publication date: Available online 15 April 2019Source: Materials Science and Engineering: AAuthor(s): Yingmei Tan, Ruirun Chen, Yangli Liu, Hongsheng Ding, Yanqing Su, Jingjie Guo, Hengzhi FuAbstractThe synergistic effects of B and N on the microstructure evolution, mechanical properties and fracture behavior of Ti46Al4Nb1Mo alloy were investigated by adding BN particles. Ti46Al4Nb1Mo-xB-xN (x = 0, 0.4%, 0.8%, 1.2%, 1.6%, atomic percent, hereafter in at.%) alloys were prepared by vacuum arc melting. Compared with Ti46Al4Nb1Mo alloy, B2 phase disappeared and curvy TiB phase appeared at the interdendritic region in Ti46Al4Nb1Mo-0.4B-0.4 N alloy. When 0.8% B and 0.8% N were added, Ti2AlN particles appeared in α2/γ lamellar colonies, tiny TiB particles and a few curvy TiB phases formed both at lamellar boundaries and lamellar colonies. With further increasing B and N content, the volume fraction of Ti2AlN and tiny TiB phases increased, and some long TiB phases appeared in Ti46Al4Nb1Mo-1.6B-1.6 N alloy. Ti2AlN and TiB phases formed by the reaction between Ti46Al4Nb1Mo alloy and BN particles. The different formation mechanism between Ti2AlN and TiB was related to the different solid solubility of B and N in Ti46Al4Nb1Mo alloy and solute redistribution during solidification process. When the content of B and N increased from 0 to 1.2%, the average lamellar colony size decreased from 358.4 μm to 48.7 μm, which resulted from synergistic effect of Ti2AlN and TiB. Compr...
Source: Materials Science and Engineering: A - Category: Materials Science Source Type: research