Composites toughening mechanisms

Rice RW, Ceramic matrix composite toughening mechanisms. An update. Ceramic Eng Sci Proc, 5(7-8), 589-607, 1985. 

Ceramic composite toughening mechanisms are briefly reviewed pertinent... 

Rubber-toughened polystyrene composites were obtained similarly by polymerising the dispersed phase of a styrene/SBS solution o/w HIPE [171], or a styrene/MMA/(SBS or butyl methacrylate) o/w HIPE [172], The latter materials were found to be tougher, however, all polymer composites had mechanical properties comparable to bulk materials. Other rubber composite materials have been prepared from PVC and poly(butyl methacrylate) (PBMA) [173], via three routes a) blending partially polymerised o/w HIPEs of vi-nylidene chloride (VDC) and BMA, followed by complete polymerisation b) employing a solution of PBMA in VDC as the dispersed phase, with subsequent polymerisation and c) blending partially polymerised VDC HIPE with BMA monomer, then polymerisation. All materials obtained possessed mixtures of both homopolymers plus some copolymer, and had better mechanical properties than the linear copolymers. The third method was found to produce the best material. 

Reprint from Acta Materialia, Vol. 52, Xia Z., Ricster L., Curtin W.A., LiH., Sheldon B.W., Liang J., Chang B. and Xu J.M., Direct observation of toughening mechanisms in carbon nanotube ceramic matrix composites, pages 931-944, Copyright (2004) with permission from Elsevier. 

Toughening mechanisms in a/p-sialon composites are similar to those operative in second-phase particle reinforced composites, but, rather than the deliberate addition of a second phase, a/P-sialon composites are fabricated by simultaneous crystallisation of the two solid solutions a- and P-sialon from a eutectic composition liquid. This requires careful design of the starting composition which is usually located within the (a + P)-sialon region of the a-sialon plane as illustrated in Fig. 18.1. 

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