Mechanical Behavior And Failure Mechanisms Of Boron Carbide Based Three-Layered Laminates With Weak Interfaces

The effect of weak interfaces on failure mechanisms of a three-layered composite was studied. Three-layered B4C/B4C-C nanofibers laminates have been produced using a hot pressing technique. The laminates were designed with thick (∼2.6 mm) outer layers of B4C and a thin (∼90 μm) center layer of B4C-70 wt.% Cnanofibers. Based on the difference in coefficients of thermal expansion and Young\u27s moduli of the pure B4C and B4C-70 wt.% Cnanofibers layers, it was estimated that low tensile thermal residual stress with a magnitude of 11.3 ± 2.5 MPa was developed in the thick B4C outer layers, and compressive residual stress with a magnitude of 455.7 ± 5 MPa was developed in the thin central B 4C-70 wt.% Cnanofibers layer. The apparent fracture toughness of laminates was measured and based on the estimated fracture toughness values, a threshold stress was calculated. © 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved