Growth plastic void

In addition to the cavitation process related to the presence of a dispersed phase, the formation of voids in the plastic zone has been observed to occur also in the matrix phase. Kinloch and Huang stated that the plastic void growth succeeding cavitation also contributes to energy absorption and might become as important as the shear banding, especially at fairly elevated temperatures [161]. 

Huang, Y. Kinloch, A.J. The role of plastic void growth in the fracture of rubber-toughened epoxy polymers. J. Mater. Sci. Lett. 1992, 11, 484-489. 

B. Debonding between nanoparticle and matrix and plastic void growth... 

Figure 9.35 Scanning electron micrographs showing the mirror zone in tensile fracture surfaces of (a) neat polymer, (h) (c) and (d) 10 phr NT-Al Oj nanocomposites, (e, f and g) 10 phr APTES-Al Oj nanocomposites. Toughening mechanisms (A) particle pull-out, and (B) dehonding and plastic void growth. The large arrow on the right bottom corner of each picture indicates the crack propagation direction. Reprinted from [97] with permission from Elsevier.

Figure 17.3 A schematic representation of plastic void growth and matrix shear banding mechanisms observed to be involved in the fracture of nanosihca-fiUed epoxy resins. Reprinted from Polymer, 53, Dittanet, P., Pearson, R.A., Effect of silica nanoparticle size on toughening mechanisms of filled epoxy, 1890—1905, Copyright (2012), with permission from...

The toughening mechanisms of silica nanoparticle-modified epoxy have been identified as plastic shear-yielding, and debonding of the polymer from the nanoparticles, followed by plastic void-growth of the epoxy (Hsieh et al. 2010). The toughening mechanisms of crack pinning, crack deflection, and immobilized polymer around the particles have all been discounted (Johnsen et al. 2007). 

Not all fracture is by crack propagation. Highly ductile materials stressed at high temperature will eventually break by the growth, through absorption of lattice vacancies, of plastic voids. This shades into the phenomenon of superplasticity, which was examined in Section 4.2.5. 

AGV is proportional to the void growth and plasticity parameters of the matrix. 

M.F. Horstemeyer et al Micromechanical finite element calculations of temperature and void configuration effects on void growth and coalescence. Int J. Plasticity 16, 979-1015 (2000)... 

G.P. Potimiche et al A molecular dynamics study of void growth and coalescence in single crystal nickel. Int. J. Plasticity 22, 257-278 (2006)... 

Needleman, A., Tvergaard, V., and Hutchinson, J. W. (1992) Void growth in plastic solids, in Topics in Fracture and Fatigue, edited by Argon, A. S., New York Springer-Verlag, pp. 145-178. 

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