Subcritical crack growth behavior of a perovskite‐structured Ba0.5Sr0.5Co0.8Fe0.2O3−δ oxygen transport membrane |
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| Authors: | Li Wang Rui Dou Gong Wang Yizhe Li Mingwen Bai David Hall Ying Chen |
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| Affiliation: | 1. School of Materials, University of Manchester, Manchester, UK;2. Technology and Engineering Centre for Space Utilisation, Chinese Academy of Science, Beijing, China |
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| Abstract: | This paper herein studies subcritical crack growth (SCG) behavior of a perovskite‐structured Ba0.5Sr0.5Co0.8Fe0.2O3?δ (BSCF) as an oxygen transport membrane material. The SCG behavior of BSCF is evaluated by a constant load method and constant stress rate method at room temperature (RT) and 800°C in air, respectively. The low crack velocity measurements are carried out by ring‐on‐ring bending tests while the high crack velocity measurements by compact tension tests. The stress rates vary approximately from 0.1012 to 101.2 MPa/min. The fracture stress increases with increasing stress rate at 800°C. The SCG parameter, n, of BSCF is determined to be 24.32 and 13.83 at RT and 800°C in air, respectively. This indicates that BSCF is more susceptible to SCG at 800°C. The strength‐probability‐time (SPT) diagram is constructed for design proposes. The stress for a lifetime of 40 years should not exceed 27.21 MPa at RT or 4.53 MPa at 800°C to assure a failure probability below 1%. |
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| Keywords: | Ba0 5Sr0 5Co0 8Fe0 2O3− δ lifetime SPT diagram stress rate subcritical crack growth |
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