Abstract: In Hutchinson's (1987) opinion, there are two sources of microcrack shielding, one is the reduction in the effective elastic moduli resulting from microcracking and the other is the strain arising from the release of residual stresses when micro-cracks are formed. This residual stresses in question develop in the fabrication of polycrystalline or multi-phase materials due to thermal mismatches between phases or thermal anisotropies of the single crystals. In this paper, besides the two sources of the redi...