The effect of thermo-mechanical treatment on the high temperature tensile behavior of an alumina-forming austenitic steel

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:651

Article

Hu, Bin¹  Baker, Ian¹ 

[1] Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA

关键词: Alumina-forming austenitic steel;    Strain rate sensitivity;    Activation volume;    Strain rate jump tests;    Deformation mechanism;    Dynamic strain aging;   

DOI  :  10.1016/j.msea.2015.11.036

来源: Elsevier

【 摘 要 】

Two different thermo-mechanical treatments (TMT) were performed on an alumina-forming austenitic (AFA) stainless steel, DAFA 29, which was recently developed at Oak Ridge National Laboratory for application in advanced ultra supercritical power plants. The resulting fine-grained TMT materials showed yield stresses more than double the yield stress of the as-received material at room temperature and more than 50% higher at 600 degrees C, but lower yield stresses (but greater elongations) at 700 degrees C and above. Strain rate jump tests performed at both 600 degrees C and 700 degrees C showed that the TMT materials have greater strain rate sensitivity and lower activation volumes at both temperatures. The strain rate has a power law relationship with the flow stress with a stress exponent of similar to 5. The as-received AFA alloy showed serrated stress-strain curves at 600 relationship with the flow stress with a stress exponent of 5. The as-received AFA alloy showed serrated C suggesting the occurrence of dynamic strain aging. (c) 2015 Elsevier B.V. All rights reserved.

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