Micro-magnetic evaluation of micro residual stresses of the IInd and IIIrd order

Micro residual stresses (MRS) of the IInd and IIInd order play all important role in the fracture mechanical analysis of thermally cycled materials, and thus ill lifetime analysis of such affected components. In multi-phase materials there call exist two kinds of MRS: thermally induced MRS of the Mid order and coherent MRS of IIIrd order. The thermally induced stresses of the IInd order appear when individual material phases exhibit different thermal expansion coefficients. The coherent MRS of the IIIrd order appear when the lattice parameter of the second phase particles embedded coherently in the matrix and the lattice parameter of the matrix are different. The main emphasis of the presented research work is the development of a micro-magnetic non-destructive technique for quantitative characterization and separation of MRS of IInd and IIIrd order in iron-based materials. (c) 2009 Elsevier Ltd. All rights reserved.