Grain boundary sliding mechanism in plastic deformation of nano-grained YAG transparent ceramics: Generalized self-consistent model and nanoindentation experimental validation

2017 ◽  
Vol 37 (7) ◽  
pp. 2705-2715 ◽  
Author(s):  
Haomin Wang ◽  
Ruijie Li ◽  
Min Zhou ◽  
Julie Cedelle ◽  
Zhiyong Huang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Boundary ◽  
Experimental Validation ◽  
Grain Boundary Sliding ◽  
Transparent Ceramics ◽  
Consistent Model ◽  
Sliding Mechanism ◽  
Self Consistent ◽  
Boundary Sliding

The Effect of Grain Boundary State on Deformation Process Development in Nanostructured Metals Produced by the Methods of Severe Plastic Deformation

2011 ◽  
Vol 683 ◽  
pp. 69-79 ◽  
Author(s):  
Evgeny V. Naydenkin ◽  
Galina P. Grabovetskaya ◽  
Konstantin Ivanov
Keyword(s):  
Plastic Deformation ◽  
Grain Boundary ◽  
Severe Plastic Deformation ◽  
Deformation Process ◽  
Process Development ◽  
Grain Boundary Sliding ◽  
Total Deformation ◽  
Nanostructured Metals ◽  
Boundary State ◽  
Boundary Sliding

In this review the investigations of deformation process development are discussed which were carried out by tension and creep in the temperature range Т<0.4Tm (here Тm is the absolute melting point of material) for nanostructured metals produced by the methods of severe plastic deformation. The contribution of grain boundary sliding to the total deformation in the above temperature interval is also considered. An analysis is made of the effect of grain size and grain boundary state on the evolution of grain boundary sliding and cooperative grain boundary sliding in nanostructured metals.

Slip Induced Strain Rate Sensitivity for Superplastic Material?

2012 ◽  
Vol 735 ◽  
pp. 31-36 ◽  
Author(s):  
Hector Basoalto ◽  
Paul L. Blackwell
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Dislocation Slip ◽  
Microstructural Parameters ◽  
Sliding Mechanism ◽  
Physically Based ◽  
Boundary Sliding

The conventional consensus has it that the magnitude of the strain rate sensitivity observed in superplastic materials is linked with grain boundary sliding. The grain boundary sliding mechanism is thought to theoretically produce a strain rate sensitivity exponent of 0.5, which is in good agreement with experimental data. The present paper argues that a rate sensitivity of 0.5 can be generated by dislocation slip under certain temperature and strain rate regimes that overlap with conditions representative of superplasticity. A physically based slip model that links the relevant microstructural parameters to the macroscopic strain rate is proposed.

Influence of Second Phases on the Superplasticity of Mg-Tm-Y-CeMM Alloys Containing LPSO-Phases

2016 ◽  
Vol 879 ◽  
pp. 1477-1482
Author(s):  
Pablo Pérez Zubiaur ◽  
Judith Medina ◽  
Gerardo Garcés ◽  
Paloma Adeva
Keyword(s):  
Grain Boundary ◽  
Earth Element ◽  
Volume Fraction ◽  
Grain Boundary Sliding ◽  
Metal Alloys ◽  
Lpso Phase ◽  
Transition Metal Alloys ◽  
Sliding Mechanism ◽  
Second Phases ◽  
Boundary Sliding

The effect of the nature of the second phases in extruded Mg-TM-Y-CeMM (TM refers to a transition metal) alloys reinforced by intermetallic MgRE (RE refers to a rare earth element) compounds and LPSO-phase on their superplasticity has been evaluated between 300 and 400°C at the strain rate of 10-4 s-1. The data have been compared with those of alloys containing a similar volume fraction of the LPSO-phase. The results evidence that no superplasticity below 350°C was found in the alloys containing exclusively the LPSO-phase while the alloys containing both MgRE compounds and LPSO-phase deform superplastically by grain boundary sliding from 300°C. These differences are related to the different behaviour of MgRE compounds and LPSO-phase in the course of superplastic regime. MgRE compounds assist to accommodate the deformation more easily than LPSO-phase, reducing tendency to develop cavities and extending the time for the occurrence of necking. The size and volume fraction of the respective phases are critical in order to promote enhanced superplastic behaviour. Maximum elongations are attained in the alloys combining similar volume fractions of MgRE compounds and LPSO-phase in which their size is reduced to the maximum. An increase in the particle size of the second phases, especially in the case of the LPSO-phase, hinders the grain boundary sliding mechanism in the alloys.

Sign in / Sign up

Export Citation Format

Share Document