Fracture mechanisms and microstructure in a medium Mn quenching and partitioning steel exhibiting macrosegregation

Fracture mechanisms and microstructure in a medium Mn quenching and partitioning steel exhibiting macrosegregation

Hidalgo Garcia, J. (TU Delft (OLD) MSE-3)
Celada-Casero, Carola (TU Delft (OLD) MSE-3)
Santofimia, Maria Jesus (TU Delft (OLD) MSE-3)

2019

A medium-Mn steel, exhibiting manganese macrosegregation, was investigated. In order to study how the microstructure development influences the fracture mechanisms, the steel was quenching and partitioning processed using two different partitioning temperatures. At 400 °C partitioning temperature, the microstructure exhibits intergranular fracture at low plastic strain, following Mn-rich regions in which fresh martensite predominates. Elongated thin precipitates at prior austenite grain boundaries facilitate the initiation and progress of cracks at these locations. After partitioning at 500 °C, the redistribution of carbon triggers the formation of pearlite, the precipitation of carbides in the carbon-enriched austenite and the formation of spheroidal carbides at prior austenite grain boundaries. All these microstructural features result in an interlath fracture with more ductile character than after partitioning at 400 °C. In both cases, manganese macrosegregation triggers brittle fracture mechanisms by creating large hardness gradients.

Fracture mechanisms
Medium manganese steels
Microstructure
Quenching and partitioning

http://resolver.tudelft.nl/uuid:519efbce-44f7-4c19-b841-431541f3712b

https://doi.org/10.1016/j.msea.2019.03.055

0921-5093

Materials Science and Engineering A: Structural Materials: Properties, Microstructures and Processing, 754, 766-777

Institutional Repository

journal article

© 2019 J. Hidalgo Garcia, Carola Celada-Casero, Maria Jesus Santofimia