Particle sintering stress

The initial sintering stress is dependent upon only the dihedral an e. The application of stress on a string of particles will affect the chemical potential at the grain boundary and, more important, determine the sintering rate. The chemical potential of a surface atom is given by [9]... 

Figure 8.31 Data of Gregg and Rhines (55) for the sintering stress versus relative density for 30 xm copper particles, determined by the zero-creep technique.

Another way to deflect cracks are residual stresses caused by the particles. Compressive stresses reduce the force opening the crack tip and thus repel cracks. Such residual stresses can stem from differences in the coefficient of thermal expansion of the particles or from phase transformations on cooling from the sintering temperature. 

Densification during liquid-phase sintering occurs in tliree stages. Initially, liquid fonns at particle intersections and redistributes tliroughout the particulate mass under the influence of the capillary action. Shear stresses due to the... 

Because nanocomposites are made from different phases with different thermal expansion coefficients and elastic moduli, they inevitably develop residual thermal stress during cooling after sintering. Assuming the dispersion phase is spherical particulate in the matrix material, residual stresses can be developed due to differences in the thermal expansion and elastic constants between the matrix and the particles [23] ... 

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