Influence of the Microstructure of Duplex Stainless Steels on their Failure Characteristics During Hot Deformation



Document title: Influence of the Microstructure of Duplex Stainless Steels on their Failure Characteristics During Hot Deformation
Journal: Materials research
Database: PERIÓDICA
System number: 000312456
ISSN: 1516-1439
Authors: 1

Institutions: 1Universidade Federal de Sao Carlos, Departamento de Engenharia de Materiais, Sao Carlos, Sao Paulo. Brasil
Year:
Season: Abr
Volumen: 3
Number: 2
Pages: 31-35
Country: Brasil
Language: Inglés
Document type: Artículo
Approach: Experimental
English abstract Two types of duplex stainless steels were deformed by torsion at a temperature range of 900 to 1200 °C and strain rate of 1.0 s-1 and their final microstructures were observed. The austenite volume fraction of steel A (26.5Cr - 4.9Ni - 1.6Mo) is approximately 25% at room temperature, after conventional annealing, while that of steel B (24Cr - 7.5Ni - 2.3Mo) is around 55%. Experimental data show that steel A is ductile at high temperatures and displays low ductility at low temperatures, while steel B has low ductility in the entire range of temperatures studied. At high temperatures, steel A is essentially ferritic and shows dynamic recrystallized grains after deformation. When steel A is strained at low temperatures and displays low austenite volume fraction, microstructural observations indicate that failure is triggered by grain boundary sliding due to the formation of an austenite net structure at the ferrite grain boundaries. At intermediate volume fraction, when austenite forms a dispersed second-phase in steels A and B, failure begins at the ferrite/ferrite boundaries since some of the new ferrite grains may become immobilized by the austenite particles. When steel B is strained at volume fraction of around 50% of austenite and both phases percolate the microstructure, failure occurs after low straining as a consequence of the different plastic behaviors of each of the phases. The failure characteristics of both steels are correlated not only with the volume fraction of austenite but also with its distribution within the ferr
Disciplines: Ingeniería
Keyword: Ingeniería de materiales,
Acero inoxidable,
Ductilidad,
Microestructuras,
Alta temperatura
Keyword: Engineering,
Materials engineering,
Stainless steel,
Ductility,
Microstructures,
High temperature
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