In-situ transmission electron microscopy investigation of compressive deformation in interphase-precipitated carbide-strengthened �\-iron single-crystal nanopillars
Journal
Materials Science and Engineering A
Journal Volume
746
Pages
406-415
Date Issued
2019
Author(s)
Gao, M.-Y.
Tsai, S.-P.
Yang, J.-R.
Chang, Y.-L.
Ohmura, T.
Chen, C.-Y.
Wang, S.-H.
Wang, Y.-T.
Abstract
Compressive deformation tests were carried out during in-situ transmission electron microscopy to investigate the deformation behaviors of α-iron nanopillars with or without interphase-precipitated carbides. Three kinds of α-iron nanopillars were prepared from titanium-molybdenum-free and titanium-molybdenum-containing steels: one interphase-precipitated carbide-free and two interphase-precipitated carbide-bearing pillars with carbides of different sizes (4.7 nm and 3.0 nm after holding at 700 °C and 650 °C, respectively) and different number densities. In-situ observation provided direct evidence that interphase-precipitated nanometer-sized carbides confined the movement of the dislocations, resulting in smaller strain bursts with a significantly higher strength, in contrast to the behaviors of the pillars without carbides. The individual strain bursts in the in-situ stress-strain curves, which were associated with the corresponding dislocation substructures in the three kinds of pillars, are discussed.
Type
journal article