Quenching and Tempering: Multicomponent Grain Boundary Segregations Design Simulation

2016 ◽  
pp. 2794-2823
Author(s):  
Anatoli Kovalev ◽  
Dmitry L. Wainstein
Keyword(s):  
Grain Boundary ◽  
Quenching And Tempering ◽  
Grain Boundary Segregations

Grain Boundary Design of Bulk Nanomaterials for Advanced Properties

2015 ◽  
Vol 5 ◽  
pp. 43-54 ◽  
Author(s):  
Ruslan Z. Valiev
Keyword(s):  
Plastic Deformation ◽  
Grain Boundary ◽  
Severe Plastic Deformation ◽  
Grain Boundaries ◽  
Metals And Alloys ◽  
New Approach ◽  
Petch Relation ◽  
Ultrafine Grained ◽  
Grain Boundary Segregations ◽  
Bulk Nanomaterials

Nanostructuring of metals and alloys by severe plastic deformation techniques is an effective way of enhancing their mechanical and functional properties. The features of the nanostructured materials produced by severe plastic deformation (SPD) are stipulated by forming of ultrafine-sized grains as well as by the state of grain boundaries. The concept of grain boundary (GB) design of ultrafine-grained metals and alloys is developed for enhancement of their properties by tailoring grain boundaries of different types (low-angle and high-angle ones, special and random, equilibrium and nonequilibrium) and formation of grain boundary segregations and precipitations by SPD processing. The paper presents experimental data demonstrating the super-strength and “positive” slope of the Hall-Petch relation when passing from micro-to nanostructured state in a number of metallic materials subjected to severe plastic deformation. The nature of the superior strength is associated with new strengthening mechanisms and the difficulty of generation of dislocations from grain boundaries with segregations. This new approach is used for achieving the enhanced strength in several commercial Al and Ti alloys as well as steels subjected to SPD processing.

The Microstructures and Grain Boundary Segregations of Ceramic Barium Titanate Processed in Microwave Field

2003 ◽  
Vol 783 ◽  
Author(s):  
Hanxing Liu ◽  
Zhongqin Tian ◽  
Jian Zhou ◽  
Hongtao Yu ◽  
Long Zou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Conventional Method ◽  
Microwave Field ◽  
Boundary Segregation ◽  
Element Distribution ◽  
Processing Method ◽  
Ceramic Processing ◽  
Transmission Electron ◽  
Grain Boundary Segregations

ABSTRACTCeramic sintering in microwave field is a new ceramic processing method. In present paper, we detected the microstructures and boundary segregation of BaTiO3 ceramics which were sintered in microwave field. Scanning electron microscopy(SEM), and transmission electron microscopy(TEM), and chemical analysis methods were employed to detect the microstructure of BaTiO3, element distribution near the boundary of BaTiO3 ceramic. The results shown growth of grain of the ceramic was influenced by impurities such as acceptor, benefactor et al, and the element distribution near the grain boundary of BaTiO3 sintered in microwave field were different with that sintered in conventional method. The boundary segregations of BaTiO3 sintered in microwave field were not obvious as compared to the conventional method because the diffusion was enhanced due to the microwave field.

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