Velocity grain boundary mobility

Experimental evidences of specific ion or solute segregation and its effect on grain boundary mobility are abundant, as introduced in Section 7.2. With the segregation of solute ions, the boundary velocity can decrease considerably as a result of solute drag within a low velocity limit described in Chapter 7. Segregation of a specific ion species with an electric charge was further confirmed in a recent investigation on the effect of an electric field on... 

During the experiment the boundary displacement is recorded. Its derivative with regard to time is the velocity v of grain boundary motion, which is related to the driving force p by the boundary mobility m = v p. For convenience we use the reduced boundary mobility... 

When pores are the second phase, they are mobile and move at a velocity equal to the velocity of the grain boundary, thus Vgi, = Vp = MpFp, where the pore mobility, Mp, and the drag force on the pore, Fp, is given in Table 16.8. Separation of the pores from the grain boundaiy occurs when Vgi, > Vp [85]. Thus the pores exhibit a drag on the grain boundary velocity, giving [86]... 

When a pore at a grain boundary moves by the evaporation/condensation mechanism, the pore mobility is inversely proportional to the square of the pore radius. What is the velocity ratio of pores with a radius of r and a radius of r2 in two different samples with the same porosity Assume that the driving force of grain growth is the same for the two samples. 

In the analysis of the grain growth kinetics, the mean boundary velocity is taken as the product of the boundary mobility and the force on the boundary, that is. 

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