Grain boundary sliding in nanomaterials at elevated temperatures

There are two types of experimental material used – pure nickel and its nano-composite reinforced with nano-sized SiO2. These materials were produced by TU Clausthal, Germany. The results have shown that the creep resistance of the nickel nano-composite reinforced with nanosized SiO2 particles is higher in comparison with non-reinforced nickel. The mechanism responsible for creep behaviour is the dislocation creep at 293 K and at elevated temperatures the dislocation creep is controlled by grain boundary sliding.

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On the Fatigue Cracks of Pure Metals due to the Grain Boundary Sliding at Elevated Temperatures

Journal of the Japan Institute of Metals and Materials ◽

10.2320/jinstmet1952.29.8_757 ◽

1965 ◽

Vol 29 (8) ◽

pp. 757-763 ◽

Cited By ~ 1

Author(s):

Sakae Takeuchi ◽

Tsuneo Homma

Keyword(s):

Grain Boundary ◽

Elevated Temperatures ◽

Fatigue Cracks ◽

Grain Boundary Sliding ◽

Boundary Sliding ◽

Pure Metals

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Superplastic Deformation Mechanisms in Fine-Grained 2050 Al-Cu-Li Alloys

Materials ◽

10.3390/ma13122705 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2705

Author(s):

Hongping Li ◽

Xiaodong Liu ◽

Quan Sun ◽

Lingying Ye ◽

Xinming Zhang

Keyword(s):

Grain Boundary ◽

Superplastic Deformation ◽

Elevated Temperatures ◽

Bulk Diffusion ◽

Grain Boundary Sliding ◽

Coordination Mechanism ◽

Diffusion Creep ◽

Fine Grained ◽

Quantitative Calculation ◽

Boundary Sliding

The deformation behavior and microstructural evolution of fine-grained 2050 alloys at elevated temperatures and slow strain rates were investigated. The results showed that significant dynamic anisotropic grain growth occurred at the primary stage of deformation. Insignificant dislocation activity, particle-free zones, and the complete progress of grain neighbor switching based on diffusion creep were observed during superplastic deformation. Quantitative calculation showed that diffusion creep was the dominant mechanism in the superplastic deformation process, and that grain boundary sliding was involved as a coordination mechanism. Surface studies indicated that the diffusional transport of materials was accomplished mostly through the grain boundary, and that the effect of the bulk diffusion was not significant.

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Examination of Fracture Interfaces in Silicon Nitride

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113925 ◽

1975 ◽

Vol 33 ◽

pp. 60-61

Author(s):

Nancy J. Tighe

Keyword(s):

Silicon Nitride ◽

Grain Boundary ◽

Crack Growth ◽

Subcritical Crack Growth ◽

Slow Crack Growth ◽

Ceramic Materials ◽

Grain Boundary Sliding ◽

Boundary Phase ◽

Turbine Engines ◽

Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

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