Hot Workability of a Spark Plasma Sintered Intermetallic Iron Aluminide Alloy Above and Below the Order-disorder Transition Temperature

被引：6

作者：

Emdadi, Aliakbar ^{[1
]}

Sizova, Irina ^{[1
]}

Stryzhyboroda, Oleg ^{[2
]}

Hecht, Ulrike ^{[2
]}

Buhl, Johannes ^{[1
]}

Bambach, Markus ^{[1
]}

机构：

[1] Brandenburg Univ Technol Cottbus Senftenbereg, Chair Mech Design & Mfg, Konrad Wachsmann Allee 17, D-03046 Cottbus, Germany

[2] Access eV, Intzestr 5, D-52072 Aachen, Germany

来源：

23RD INTERNATIONAL CONFERENCE ON MATERIAL FORMING | 2020年 / 47卷

关键词：

Iron aluminides; Fe3Al-1.5Ta alloy; Hot workability; Processing maps; Order-disorder transition; DEFORMATION-BEHAVIOR;

D O I：

10.1016/j.promfg.2020.04.238

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The Fe-25Al-1.5Ta alloy has proved to be qualified for structural applications at and above 600 degrees C due to a superior creep resistance to its binary counterpart. The creep resistance of the Fe-25Al-1.5Ta alloy at 650 degrees C surpasses that of the P92 martensitic-ferritic steel, which is one of the most developed creep resistant alloys for steam turbine applications. From the viewpoint of cost-effectiveness in real-scale forgings, it is important to safely deform the material at as low as possible temperatures. Based on Thermo-Calc computations, the Fe-25Al-1.5Ta alloy shows a B2-to-A2 order-disorder transition at around 860 degrees C. This paper investigates the hot compression behavior and microstructural evolution of a Fe-25Al-1.5Ta alloy deformed in the disordered A2 (900-1100 degrees C) and ordered B2 (800-850 degrees C) regimes. Effects of ordering on plastic deformation, energy dissipation efficiency and instability parameters are identified using the concept of processing maps, and the underlying deformation mechanisms are characterized using scanning electron microscopy and electron back-scattered diffraction. The samples deformed in the A2 disorder region showed no flow instability for the deformation conditions tested, while the specimens deformed in the ordered B2 region revealed a region of flow instability located at 900 degrees C/1s(-1). The observed flow instability region manifests itself in a longitudinal surface crack formed in the samples deformed at 900 degrees C/1s(-1). The change of activation energy of hot deformation and efficiency of energy dissipation are discussed based on the ordering effect and movement of super-dislocations in the B2 regime. The current study identifies processing parameters to safely deform the Fe-25Al-1.5Ta alloy at lower temperatures of 800 degrees C and at strain rates below 1s(-1). (C) 2020 The Authors. Published by Elsevier Ltd.

引用

页码：1281 / 1287

页数：7

共 14 条

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