Relationship between microstructure and fracture types in a UNS S32205 duplex stainless steel

Materials Research

Maria Victoria Biezma²  Carlos Berlanga¹  Gorka Argandona¹ 

[1] ,University of Cantabria Department of Earth, Materials Science and Engineering Santander,Spain

关键词: duplex stainless steel;    sigma phase;    microstructure;    fractography;   

DOI  :  10.1590/S1516-14392013005000085

来源: SciELO

【 摘 要 】

Duplex stainless steels are susceptible to the formation of sigma phase at high temperature which could potentially be responsible for catastrophic service failure of components. Thermal treatments were applied to duplex stainless steels in order to promote the precipitation of different fractions of sigma phase into a ferrite-austenite microstructure. Quantitative image analysis was employed to characterize the microstructure and Charpy impact tests were used in order to evaluate the mechanical degradation caused by sigma phase presence. The fracture morphology of the Charpy test specimens were thoroughly observed in SEM, looking for a correlation between the microstructure and the fracture types in UNS S32205 duplex stainless steel. The main conclusion is the strong embrittlement effect of sigma phase since it is possible to observe a transition from transgranular fracture to intergranular fracture as increases the percentage of sigma phase. Thus, the mixed modes of fracture are predominant in the present study with high dependence on sigma phase percentages obtained by different thermal treatments.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License