Effects of low-temperature asuforming on the miscrostructural evolution in Fe-0.6C-2Si-xMn (x=1, 2, wt%) nanobainitic steels
Date Issued
2015
Date
2015
Author(s)
Tung, Po-Yen
Abstract
Nanostructured bainite, having high potential as the bulletproofing material, has been studied for many years. Nanostructured bainite possesses high strength, high elongation, but its low toughness due to the instability of blocky austenite is a serious disadvantage. So, the primary propose in this work is to improve the properties of blocky austenite. First, we introduce ausforming process—plastic deformation at low temperature before isothermal bainitic transformaiton—to change the microstructure of traditional nanostructured bainite. Second, we further measure the stability of blocky austenite in ausformed bainite by EBSD. Besides, the orientation relationship between blocky austenite and bainitic ferrite is analyzed by EBSD. In ausformed bainite, the blocky austenite and bainitic sheaves are simultaneously refined and well-distributed. The refined blocky austenite is further mechanical stabilized by ausforming process, which might benefit to mechanical properties. Due to ausforming process, variant selection is assisted by Shockley partial dislocations and measured by EBSD.
Subjects
low-temperature ausforming
mechanical stabilization of austenite
nanobainite structure
retained blocky austenite
pole-figure
thermal stability of austenite
Type
thesis
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