The effect of grain size on the twin initiation stress in a TWIP steel

By K. Rahman, V. Vorontsov, D. Dye. 2015

282 citations recorded by the source corpus.

Abstract The influence of grain size on the twinning stress of an Fe–15Mn–2Al–2Si–0.7C Twinning Induced Plasticity (TWIP) steel has been investigated. Five grain sizes were obtained using a combination of cold rolling and annealing. Electron backscatter diffraction (EBSD) analysis revealed that the material exhibited a typical cold rolled and annealed texture. Tensile testing showed the yield stress to increase with decreasing grain size, however, the ductility of the material was not substantially affected by a reduction in grain size. Cyclic tensile testing at sub-yield stresses indicated the accumulation of plastic strain with each cycle, consequently the nucleation stress for twinning was determined. The twin stress was found to increase with decreasing grain size. Furthermore, the amount of strain accumulated was greater in the coarser grain material. It is believed that this is due to a difference in the twin thickness, which is influenced by the initial grain size of the material. SEM and TEM analysis of the material deformed to 5% strain revealed thinner primary twins in the fine grain material compared to the coarse grain. TEM examination also showed the dislocation arrangement is affected by the grain size. Furthermore, a larger fraction of stacking faults was observed in the coarse-grained material. It is concluded that the twin nucleation stress and also the thickness of the deformation twins in a TWIP steel, is influenced by the initial grain size of the material. In addition grain refinement results in a boost in strength and energy absorption capabilities in the material.

Subfields: Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/df82a734a80ddf1e9adaea0b84d41235788d7606

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In Materials Chemistry

1. Zhiming Li
2. J. Su
3. D. Dye
4. Dierk Raabe
5. Peter D. Lee
6. Franz Roters
7. O. A. Zambrano
8. Philip Eisenlohr

In Mechanical Engineering

1. Zhiming Li
2. J. Su
3. Dierk Raabe
4. Yong Liu
5. D. Dye
6. Saurabh Kabra
7. Peter D. Lee
8. Paul A. Hooper

Citations in the corpus

• Understanding martensite and twin formation in austenitic steels: A model describing TRIP and TWIP effects (2017, unknown): “…and twinning is less likely to occur in fine–grained alloys, as higher stress levels are required for dislocations to propagate and promote stacking fault formation; this is consistent with experimental evidence showing that twin and α activity decreases with decreasing the grain size [34, 35].”
• Hierarchical microstructure design to tune the mechanical behavior of an interstitial TRIP-TWIP high-entropy alloy (2019, background): “More specific, both mechanisms have been reported to show strong dependence on grain size and local partitioning of the alloying elements [16,17].”
• Probing deformation mechanisms of a FeCoCrNi high-entropy alloy at 293 and 77 K using in situ neutron diffraction (2018, background): “of research recently as it is one of the micro-mechanistic mechanisms that can overcome 56 the strength-ductility trade-off, which has been demonstrated by fcc metals and alloys 57 with low stacking fault energy (SFE) such as the tHEAs and TWIP steels [9-11].”
• Twinning induced plasticity in austenitic stainless steel 316L made by additive manufacturing (2017, result): “This observation is in agreement with other studies of twinning-induced plasticity [14-16].”