Evolution of microstructures in a nanotwinned steel investigated by nanoindentation and electrical resistivity measurement
A twinning-induced plasticity(TWIP)steel was subjected to cold rolling followed by recovery heat treatment,forming a nanotwinned steel.During the recovery annealing,the nanotwins are thermally stable so that they remain in the sample after recovery annealing.On the contrary,the dislocation density was reduced greatly after recovery annealing.The nanotwinned steel possesses a high yield strength,high ultimate tensile strength and good ductility.The nanohardness tests and electrical resistivity measurements illustrate that the dislocation density increases dramatically in the nanotwinned steel during the tensile test while the twin volume fraction remains constant.The transmission electron microscopy(TEM)observation confirms the results from nanoindentation and electrical resistivity tests.The maximum volume fraction of deformation twins has been reached during the heavy cold rolling so that no more new deformation twins can be generated in the nanotwinned steel during tensile test.Therefore,the work hardening behaviour of the nanotwinned steel is mainly provided by the accumulation of dislocations.
Nanotwinned steel TWIP steel Nanotwins Nanoindentation Electrical resistivity
ZHOU Peng LIU Ren-dong WANG Xu HUANG Ming-xin
Department of Mechanical Engineering,The University of Hong Kong,Pokfulam Road,Hong Kong,China Iron and Steel Research Institute,Ansteel Group,Anshan,China
国内会议
上海
英文
1-6
2015-10-21（万方平台首次上网日期，不代表论文的发表时间）