Interpretation of high-temperature tensile properties by thermodynamically calculated equilibrium phase diagrams of heat-resistant austenitic cast steels
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- 作者：Seungmun Jung ; Seok Su Sohn ; Won-Mi Choi…
- 关键词：heat ; resistant austenitic cast steel ; high ; temperature tensile properties ; phase diagram ; microstructure ; strength
- 刊名：Metals and Materials International
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：23
- 期：1
- 页码：43-53
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Metallic Materials; Operating Procedures, Materials Treatment; Magnetism, Magnetic Materials; Engineering Thermodynamics, Heat and Mass Transfer; Characterization and Evaluation of Materials; Continuu
- 出版者：The Korean Institute of Metals and Materials
- ISSN：2005-4149
- 卷排序：23
文摘
High-temperature tensile properties of three heat-resistant austenitic cast steels fabricated by varying W, Mo, and Al contents were interpreted by thermodynamically calculated equilibrium phase diagrams of austenite, ferrite, and carbides as well as microstructural analyses. A two-step calculation method was adopted to cast steel microstructures below the liquid dissolution temperature because the casting route was not an equilibrium state. Thermodynamically calculated fractions of equilibrium phases were well matched with experimentally measured fractions. Ferrites existed at room and high temperatures in both equilibrium phase diagrams and actual microstructures, which has not been reported in previous researches on austenitic cast steels. In the W2Mo1Al1 steel, 38% and 12% of ferrite existed in the equilibrium phase diagram and actual microstructure, respectively, and led to the void initiation and coalescence at ferrites and consequently to the serious deterioration of high-temperature strengths. The present equilibrium phase diagrams, besides detailed microstructural analyses, effectively evaluated the high-temperature performance by estimating high-temperature equilibrium phases, and provided an important idea on whether ferrite were formed or not in the heat-resistant austenitic cast steels.