Compression deformation behavior of Zircaloy-4 alloy changing with activated twinning type at ambient temperature: experiment and modeling

2016 ◽  
Vol 49 (3) ◽  
pp. 987-996 ◽  
Author(s):  
Hongjia Li ◽  
Wupeng Cai ◽  
Zhijian Fan ◽  
Xuefei Huang ◽  
Yandong Wang ◽  
...  

It is widely accepted that twinning is important for the plastic deformation of zirconium alloys, although the corresponding roles of different types of twinning are rarely discussed. Here, the deformation behavior of Zircaloy-4 alloy at ambient temperature under compression along the rolling, transverse and normal directions of the rolled plate is studied by examination of macroscopic stress–strain curves, texture evolution andin situlattice strain, combined with elastic–plastic self-consistent simulation. It is concluded that tensile twinning {10\overline 12}〈10\overline 11〉, tensile twinning {11\overline 21}〈11\overline 26〉 and compressive twinning {11\overline 22}〈11\overline 2\overline 3〉 are the main deformation twinning types for compression along the three principal directions. A change in the activated twinning type induces differences in the plastic deformation mode and the stress/strain partitioning between parent and child grains. The work provides insight into the effects of deformation twinning on the plastic deformation behavior of Zircaloy-4 alloy.

2006 ◽  
Vol 980 ◽  
Author(s):  
Takayoshi Nakano ◽  
Koji Hagihara ◽  
Yukichi Umakoshi

AbstractPlastic deformation behavior and the dominant deformation mode in ternary (Nb1-xMox)Si2 (x=0-0.85) single crystals with the C40 structure were examined focusing on the phase stability between the C40 and C11b structures. Temperature dependence of CRSS for the (0001)<2-1-10] slip is strongly influenced by the Mo concentration accompanied by the change in the dissociation mode from the co-planar-type to the synchroshear-type. In the ternary crystals with x=0-0.30, anomalous strengthening clearly appeared, and the peak stress increased up to 1600¢ªC with an increase in the Mo content. Mo atoms may gather and form a dragging atmosphere around 1/3<2-1-10] dislocations containing a superlattice intrinsic stacking fault (SISF), resulting in anomalous strengthening. In contrast, in crystals with x=0.60-0.85, a high CRSS was obtained with fracture in a brittle manner at low temperatures, and the stress decreased remarkably with an increase in the test temperature. HRTEM observation showed that the synchroshear-type dissociation of each super-partial dislocation, 1/6<2-1-10], occurred on the neighboring slip planes, accompanied by a much wider separation distance of SF than that in the ternary crystals with a low Mo content. This change in plastic deformation behavior may be closely related to the decrease in phase stability of the C40 structure with the addition of the C11b-stabilized element, Mo. The phase stability can be represented by the ratio of (h/b), where h is the (0003) spacing and b is the amplitude of 1/3<2 0]. As the (h/b) ratio increases with the addition of Mo, the dissociation mode changes from the co-planar-type to the synchroshear-type at a ratio of 0.465.


2015 ◽  
Vol 830-831 ◽  
pp. 337-340
Author(s):  
Ashish Kumar Saxena ◽  
Manikanta Anupoju ◽  
Asim Tewari ◽  
Prita Pant

An understanding of the plastic deformation behavior of Ti6Al4V (Ti64) is of great interest because it is used in aerospace applications due to its high specific strength. In addition, Ti alloys have limited slip systems due to hexagonal crystal structure; hence twinning plays an important role in plastic deformation. The present work focuses upon the grain size effect on plastic deformation behaviour of Ti64. Various microstructures with different grain size were developed via annealing of Ti64 alloy in α-β phase regime (825°C and 850°C) for 4 hours followed by air cooling. The deformation behavior of these samples was investigated at various deformation temperature and strain rate conditions. Detailed microstructure studies showed that (i) smaller grains undergoes twinning only at low temperature and high strain rate, (ii) large grain samples undergo twinning at all temperatures & strain rates, though the extent of twinning varied.


1975 ◽  
Vol 18 (125) ◽  
pp. 1209-1217 ◽  
Author(s):  
Kenji KANEKO ◽  
Kozo IKEGAMI ◽  
Eiryo SHIRATORI

2015 ◽  
Vol 651-653 ◽  
pp. 570-574 ◽  
Author(s):  
Akinori Yamanaka

The plastic deformation behavior of dual-phase (DP) steel is strongly affected by its underlying three-dimensional (3D) microstructural factors such as spatial distribution and morphology of ferrite and martensite phases. In this paper, we present a coupled simulation method by the multi-phase-field (MPF) model and the crystal plasticity fast Fourier transformation (CPFFT) model to investigate the 3D microstructure-dependent plastic deformation behavior of DP steel. The MPF model is employed to generate a 3D digital image of DP microstructure, which is utilized to create a 3D representative volume element (RVE). Furthermore, the CPFFT simulation of tensile deformation of DP steel is performed using the 3D RVE. Through the simulations, we demonstrate the stress and strain partitioning behaviors in DP steel depending on the 3D morphology of DP microstructure can be investigated consistently.


2007 ◽  
Vol 345-346 ◽  
pp. 177-180 ◽  
Author(s):  
Dyi Cheng Chen ◽  
Yi Ju Li ◽  
Gow Yi Tzou

The shear plastic deformation behavior of a material during equal channel angular (ECA) extrusion is governed primarily by the die geometry, the material properties, and the processing conditions. Using commercial DEFORMTM 2D rigid-plastic finite element code, this study investigates the plastic deformation behavior of Ti-6Al-4V titanium alloy during 1- and 2-turn ECA extrusion processing in dies containing right-angle turns. The simulations investigate the distributions of the billet mesh, effective stress and effective strain under various processing conditions. The respective influences of the channel curvatures in the inner and outer regions of the channel corner are systematically examined. The numerical results provide valuable insights into the shear plastic deformation behavior of Ti-6Al-4V titanium alloy during ECA extrusion.


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