Zhan Zhongwei, Zhang Qi, Wang Shuaixing, Liu Xiaohui, Zhang Hao, Sun Zhihua, Ge Yulin, Du Nan
Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China.
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China.
Materials (Basel). 2024 Jul 4;17(13):3322. doi: 10.3390/ma17133322.
The non-equilibrium solidification process in the additive manufacturing of titanium alloy leads to special microstructures, and the resulting changes in corrosion behavior are worthy of attention. In this paper, the microstructure and electrochemical corrosion behavior of Ti6Al4V alloys prepared using laser powder bed melting (LPBF) and casting are systematically compared. The results show that the LPBF-processed Ti6Al4V alloy is composed of dominant acicular α' martensite within columnar prior β phase, and less β disperses have also been discovered, which is significantly different from the α + β dual-phase structure of cast Ti6Al4V alloy. Compared to the as-cast Ti6Al4V alloy, LPBF-processed Ti6Al4V alloy has a thinner and unstable passive film, and exhibits slightly poorer corrosion resistance, which is mainly related to its higher porosity, a large amount of acicular α' martensite and less β phase compared to as-cast Ti6Al4V alloy. This result proves that suitable methods should be taken to control the relative density and phase composition of LPBF-processed Ti6Al4V alloys before application.
钛合金增材制造中的非平衡凝固过程会导致特殊的微观结构，其腐蚀行为的变化值得关注。本文系统地比较了采用激光粉末床熔融（LPBF）和铸造工艺制备的Ti6Al4V合金的微观结构和电化学腐蚀行为。结果表明，LPBF处理的Ti6Al4V合金由柱状先共析β相内的主要针状α'马氏体组成，并且还发现有较少的β相弥散分布，这与铸造Ti6Al4V合金的α + β双相结构有显著差异。与铸造Ti6Al4V合金相比，LPBF处理的Ti6Al4V合金具有更薄且不稳定的钝化膜，耐腐蚀性稍差，这主要与其相比铸造Ti6Al4V合金具有更高的孔隙率、大量的针状α'马氏体和较少的β相有关。该结果证明在应用前应采取适当方法来控制LPBF处理的Ti6Al4V合金的相对密度和相组成。
