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Title: Microstructural characteristics of adiabatic shear localization in a metastable beta titanium alloy deformed at high strain rate and elevated temperatures

The microstructural evolution and grain refinement within adiabatic shear bands in the Ti6554 alloy deformed at high strain rates and elevated temperatures have been characterized using transmission electron microscopy. No stress drops were observed in the corresponding stress–strain curve, indicating that the initiation of adiabatic shear bands does not lead to the loss of load capacity for the Ti6554 alloy. The outer region of the shear bands mainly consists of cell structures bounded by dislocation clusters. Equiaxed subgrains in the core area of the shear band can be evolved from the subdivision of cell structures or reconstruction and transverse segmentation of dislocation clusters. It is proposed that dislocation activity dominates the grain refinement process. The rotational recrystallization mechanism may operate as the kinetic requirements for it are fulfilled. The coexistence of different substructures across the shear bands implies that the microstructural evolution inside the shear bands is not homogeneous and different grain refinement mechanisms may operate simultaneously to refine the structure. - Graphical abstract: Display Omitted - Highlights: • The microstructure within the adiabatic shear band was characterized by TEM. • No stress drops were observed in the corresponding stress–strain curve. • Dislocation activity dominated the grain refinement process. •more » The kinetic requirements for rotational recrystallization mechanism were fulfilled. • Different grain refinement mechanisms operated simultaneously to refine the structure.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1] ;  [3]
  1. Centre for Advanced Materials Processing and Manufacture, School of Mechanical and Mining Engineering, The University of Queensland, St Lucia, Queensland 4072 (Australia)
  2. State Key Laboratory of Solidification Processing, School of Materials, Northwestern Polytechnical University, Xi'an 710072 (China)
  3. (Australia)
  4. School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4575 (Australia)
Publication Date:
OSTI Identifier:
22476073
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 102; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CAPACITY; DISLOCATIONS; GRAIN REFINEMENT; MICROSTRUCTURE; RECRYSTALLIZATION; STRAIN RATE; STRAINS; STRESSES; TITANIUM ALLOYS; TITANIUM-BETA; TRANSMISSION ELECTRON MICROSCOPY