Accommodation of Grain Boundary Sliding in AZ31 Alloy

Mg alloys could be the lightest alloys among the industrially applicable engineering alloys. Since wrought Mg alloy has limited applications due to the poor formability, casting is currently the main processing technique to fabricate Mg components even though wrought alloys are superior in terms of mechanical properties and reliability. While a lot of research and development has been focused on warm forming under the temperature condition of around 250°C where more formability could be expected, superplastic forming could be another way to get over the low formability of Mg alloys. Like other superplastic materials grain boundary sliding is the main deformation mechanism of Mg superplasticity. Accommodation of stress concentration around triple point of grain boundary should be done favorably if grain boundary sliding continues without any fracture. In the present study, superplastic behavior of AZ31 alloys with several grain sizes was examined firstly. Accommodation of grain boundary sliding of AZ31 alloy would be discussed on the basis of grain morphology and texture evolution after tensile deformation.

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Periodic formations of deformation twins and dislocation arrays via grain boundary sliding at serrated grain boundary in cold-shear-strained AZ31 alloy

International Journal of Plasticity ◽

10.1016/j.ijplas.2020.102815 ◽

2020 ◽

Vol 135 ◽

pp. 102815

Author(s):

Hyeon-Woo Son ◽

Soong-Keun Hyun

Keyword(s):

Grain Boundary ◽

Az31 Alloy ◽

Grain Boundary Sliding ◽

Deformation Twins ◽

Dislocation Arrays ◽

Boundary Sliding

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Microstructural evolution and grain boundary sliding in a superplastic magnesium AZ31 alloy

Acta Materialia ◽

10.1016/j.actamat.2009.04.011 ◽

2009 ◽

Vol 57 (13) ◽

pp. 3683-3693 ◽

Cited By ~ 90

Author(s):

R. Panicker ◽

A.H. Chokshi ◽

R.K. Mishra ◽

R. Verma ◽

P.E. Krajewski

Keyword(s):

Grain Boundary ◽

Microstructural Evolution ◽

Az31 Alloy ◽

Grain Boundary Sliding ◽

Magnesium Az31 ◽

Boundary Sliding

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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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