Deformation-assisted diffusion for the enhanced kinetics of dynamic phase transformation

Abstract

Comparison on the kinetics of two different phase transformations, including phase transformation after deformation and phase transformation during deformation (i.e. dynamic transformation, DT), reveals a new discovery that the transformation kinetics can be significantly enhanced in DT even under low driving forces. DT enables continuous generation of defects (e.g. dislocations) near the phase boundary, which can act as short-circuiting diffusion paths for atoms. The diffusivity of atoms is enhanced and the activation energy for the atom jump across the phase boundary is lowered under stress during DT, resulting in more pronounced grain growth as well as accelerated transformation kinetics. IMPACT STATEMENT Deformation-enhanced grain growth is revealed in dynamic phase transformation, which will promote microstructure and property design of structural materials where phase transformations occur.

Deformation-Induced Grain-Interior α Precipitation and β Texture Evolution during the β-Processed Forging of a Near-β Titanium Alloy

“…However, recrystallization scarcely occurs during forging and cooling in the (α + β) region due to α precipitation at β gain boundaries even at a moderate cooling rate [14]. may enhance the β-to-α transformation [13]. Figure 5 shows that the acicular α phase precipitated and penetrated β grains more at 30% β deformation than at 0% and 15% β deformations under constant (α + β) forging ratios.…”

“…Those defects remain in the microstructure after deformation. In addition, the dislocationassisted diffusion through short-circuiting paths near α/β interfaces may enhance the β-to-α transformation [13]. Figure 5 shows that the acicular α phase precipitated and penetrated β grains more at 30% β deformation than at 0% and 15% β deformations under constant (α + β) forging ratios.…”

“…Metals 2021, 11, x FOR PEER REVIEW 4 of 14 may enhance the β-to-α transformation [13]. Figure 5 shows that the acicular α phase precipitated and penetrated β grains more at 30% β deformation than at 0% and 15% β deformations under constant (α + β) forging ratios.…”

Ultra-fine-Grained Ferrite Prepared from Dynamic Reversal Austenite During Warm Deformation

“…Meanwhile, the shear accommodation work and shrinkage work are expressed as Eqs. ( 2) and (3) [24,26]. Therefore,…”

Temperature-affected nano-deformation behavior of nanometals in ultrahigh-strain-rate formation processes

“…The dislocation is a favorable channel for interstitial transport, corresponding to the deformation-assisted diffusion mechanism. 39 In the thermal-promoted formability stage, the plastic behavior of nano-metals is mediated by dislocations, and the increase in temperature accelerates the nucleation and proliferation processes, which provide sufficient channels for the movement of the interstitials and facilitate the improvement of formability. There is an approximate linear relationship between the forming depth and the dislocation density (Fig.…”