Microcracks associated with inclusions in as-cast iron and their role during fracture
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The formation of voids and microcracks in and around FeO and SiO2 inclusions during the solidification of pure iron has been investigated and their role during fracture studied. The sizes of these inclusions were varied by an order of magnitude by control of the solidification rate. Voids and microcracks were associated with large (~4 μ) as well as with fine (~0.1 μ) FeO inclusions but not with SiO2 inclusions. The formation of voids is explained on the basis of solidification shrinkage and the freezing characteristics of FeO. The occurrences of microcracks in the inclusions is explained on the basis of stresses developed due to differential thermal contraction of inclusions and the surrounding matrix during cooling. The effect of these microcracks on the fracture behavior of inclusion-bearing iron is briefly described.
KeywordsFracture Surface Interface Crack Pure Iron Metallurgical Transaction Volume Fine Inclusion
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