articles of interest

Several articles worth finding:
S. Ortner (YES - Susan!), "Comparision between particle cracking criteria in models for the fracture of steels," FFEMS, V34, Issue 12, pp 956-973, Dec. 2011

J. Gurland, "Observations of the fracture of cementite particles in a spherodized 1.05% C steel deformed at room temperature," Acta Metallurgica, V20, Issue 5, May 1972

Rosenfield, Shetty, & Skidmore, "Fractographic observations of cleavage initiation in the DBT region of a RPV Steel," Metallurgica & Matls TRansactions A, V14, N9, pp 1934-1937

Zikry group at NC State

Anyone run into the work of the Zikry group before? (http://www.mae.ncsu.edu/zikry/index.html) It looks like most of the work focuses on FCC materials but some ideas may apply to DISFRAC?  Haven't chased down any papers yet but here are some interesting sounding titles.

T. Kameda, and M.A. Zikry, (2006), Modeling of Grain-Boundary Effects and Intergranular and Trangranular Failure in Polycrystalline Intermetallics, Metallurgical and Materials Transactions A , 37A, 2107-2120

O. Rezvanian and M.A. Zikry (2007), Statistically Stored, Geometrically Necessary and Grain Boundary Dislocation Densities: Microstructural Representation and Modelling, Philosophical Transactions Of The Royal Society Of London. Series A, Mathematical, Physical And Engineering Sciences, 463/ 2087, 2833-2853

Jawad, F. F., & Zikry, M. A. (2009). The effects of grain-boundary orientations on failure behavior in FCC polycrystalline systems. International Journal of Damage Mechanics², 18(4), 341-369.

Shi, J., & Zikry, M. A. (2009). Grain-boundary interactions and orientation effects on crack behavior in polycrystalline aggregates. International Journal of Solids and Structures², 46(21), 3914-3925

Rezvanian, O., Zikry, M. A., & Rajendran, A. M. (2008). Microstructural modeling in F.C.C. crystalline materials in a unified dislocation-density framework. Materials Science & Engineering. A, Structural Materials: Properties, Microstructure and Processing², 494(1-2), 80-85

Ashmawi, W. M., & Zikry, M. A. (2002). Prediction of grain-boundary interfacial mechanisms in polycrystalline materials. Journal of Engineering Materials and Technology², 124(1), 88-96

Meeting Agenda 1-20-12

Goal of the 1-20-12 DISFRAC meeting will be a verbal summary of the grain boundary model to include limits in GB energy and fracture strength as the angle of misorientation goes to zero. 

Secondary topics include discussions of the information on grain boundary properties as described in the Hirth text and the Read text in particular, and other texts as they are read!

GB references

Basic dislocations texts with chapters on grain boundaries:
Theory of Dislocations, Second Edition, by Hirth and Lothe, originally published by Wiley and Sons, reprinted by Krieger Publishing Co., Malabar, FL 1992.  Look at chapter 19 on Grain Boundaries

Elementary Dislocation Theory, by Johannes Weertman and Julia Weertman, Oxford University Press, New York, 1992  pp 187 - 195 on low angle boundaries

Mode focused book:
Interfaces in Crystalline Materials, by A.P. Sutton and R.W. Balluffi, Oxford University Press, 1995, reprinted in 2009.  Chapter 2 Dislocation models for interfaces, Chapter 4 Models and Experimental observations of atomic structures (in interfaces), Chapter 12 Mechanical properties of interfaces including Section 12.9 on Fracture of homophase interfaces (grain boundaries). 

grain boundary energy and strengths: values in the literature

• Qiao & Kong (2004) 25kJ/m work of separation of grain boundary, includes plastic dissipation.  Note units; this is per unit length grain boundary not per unit area of crack surface (or even per unit area of grain boundary).  This is used to compute the total fracture work to cross the grain boundary; 25 kJ/m * (persistent area per unit length grain boundary) = (units of kJ)
• Stec & Faleskog (2009) take the work of separation (excluding plastic deformation) to be 640 N/m in general.  Here the units are N/m = J/m^2 as necessary for their cohesive model applied to the grain boundary. They also employed values of Gamma_GB = 160, 320, & 1600 N/m.
• Stec & Faleskog (2009) cite the ideal ferrite strength = 12 GPa, but use sigma_max = 4.8 GPa to account for material defects and dissipation effects.

Kick-off to the DISFRAC Blog

Today we begin a new phase to our DISFRAC working group meetings.  Welcome to the DISFRAC blogger site!  The purpose of this blog is to keep track of all of the thoughts, ideas, research, data, and conversations in a searchable format.