Abstract: (18561 Views)
The relation between microstructure and the fracture mechanisms of δ-TRIP steel with different Nb-content has been investigated using complementary methods of light microscopy, SEM, EDS, EBSD, X-ray phase analysis and tensile test. The results revealed a close dependency between the presences of constitutive phases i.e. ferrite, bainite, retained austenite and martensite and the mode and characteristics of fracture. All samples revealed almost different fractography pattern which could be associated to the effect of Nb microalloying element. The different fractography patterns were consisted of dimple rupture, riverside and Wallner lines pattern. The proportion of the cleavage fracture in comparison of dimple rapture increased by increasing the Nb-content due to the increase of primary martensite in the microstructure.
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- The relation between microstructure and the fracture mechanisms of δ-TRIP steel with different Nb-content has been investigated.
- The amount, size and morphology of austenite remarkably change by the addition of Nb.
- The unexpected decrease of the tensile strength was occurred with increasing Nb content.
- The results revealed a close dependency between the presences of constitutive phases and the mode and characteristics of fracture.
- The different fractography patterns were consisted of dimple rupture, riverside and Wallner lines pattern.