Micromechanisms of Brittle Fracture in Titanium-Stabilized and α'-Embrittled Ferritic Stainless Steels
SourceFe-26Cr alloys, with and without titanium stabilization, have been studied in an effort to clarify the micromechanisms of brittle fracture in the presence of titanium stabilization and α'-precipitation (475°C embrittlement). Tension testing, Charpy testing and metallographic evaluations have been undertaken. Microscopic observations of electropolished strips pulled in the ductile-to-brittle transition temperature (DBTT) range have been made. Titanium stabilization can lead to DBTT increases in low carbon and nitrogen alloys and this embrittlement is associated with intergranular microcrack formation. Embrittlement due to α' -precipitation seems related to flow stress increase and the α'-precipitation is seen to bring about a gross change in slip character, leading to the development of relatively few, but extremely intense slipbands.