A Comparative Study on the Dynamic Tensile Behavior of Nanostructured Bainitic and Quenched-Tempered Martensitic Steels

Metals

RajaDevesh Kumar Misra¹  Cong Zhang²  Kaiming Wu²  Tingpin Hou²  Wen Zhou²  Lei Zhong² 

[1] Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968, USA;The State Key Laboratory of Refractories and Metallurgy, Hubei Province Key Laboratory of Systems Science on Metallurgical Processing, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081, China;

关键词: steel;    nanostructure;    bainitic transformation;    dynamic tensile test;   

DOI  :  10.3390/met8090728

来源: DOAJ

【 摘 要 】

In order to assess the dynamic tensile behavior of a newly developed three-step low-temperature-transformed bainitic microstructure, and a conventional one-step isothermal bainitic microstructure, and a quenched and tempered martensitic microstructure, a comparative research was conducted by using the dynamic tensile test. The results showed that more film-like retained austenite was obtained in the three-step low-temperature-transformed sample. The carbon content in the film-like retained austenite was found to be higher as compared to the blocky retained austenite. The dynamic tensile properties were all improved with an increase in strain rates (from 0.1 to 500 s−1). However, the three-step bainitic low-temperature-transformed sample showed the most remarkable dynamic tensile properties, including ultimate tensile strength and total elongation. This is attributed to a better transformation-induced plasticity effect that is exhibited by the higher stability of the film-like retained austenite. Therefore, the present study suggests that performing a three-step low-temperature bainitic transformation promotes grain refinement and the formation of film-like retained austenite and improves the dynamic tensile properties.

【 授权许可】

Unknown