Heterogeneous creep deformation in Dissimilar Metal Welds (DMWs)

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:749

Article

Subramanian, Mohan¹  Galler, Jonathan²  DuPont, John²  Kombaiah, Boopathy³  Yu, Xinghua³  Peng, Zhili³  Babu, Sudarsanam^1,3 

[1] Univ Tennessee, Knoxville, TN 37996 USA

[2] Lehigh Univ, Bethlehem, PA USA

[3] Oak Ridge Natl Lab, Oak Ridge, TN USA

关键词: Dissimilar metal joining;    Digital Image Correlation (DIC);    Creep;   

DOI  :  10.1016/j.msea.2019.01.075

来源: Elsevier

【 摘 要 】

Dissimilar Metal Welds (DMWs) made between ferritic low alloy steels and austenitic alloys are widely used in high temperature components of nuclear and fossil energy power plants. Literature shows that these bimetallic welds fail prematurely by creep mechanism close to the interface of the ferritic (BCC) and austenitic regions (FCC), with lifetimes much less than the creep lives of both materials. These creep failures are associated with cavity formation close to BCC/FCC interfaces. However, the spatial and temporal variations of creep strain rates in these DMWs have not been measured. In this research, DMW coupons were fabricated between 2.25Cr-1Mo steel and Alloy 800 H base material using a Ni base Inconel weld consumable. These samples were aged at 600 degrees C for 2000 h and 4000 h to induce two different sizes and distributions of Type I interfacial carbides and further subjected to a short term (similar to 1 month) creep testing. Surface strains were measured with Digital Image Correlation (DIC) technique to extract local creep strain rates. In both samples, creep strain concentration occurred in the BCC matrix. The location of creep strain concentration from the BCC/FCC interface, changed from 5 pm (2000 h aged condition) to 400 mu m (4000 h aged condition) depending on the initial carbide distributions in these regions.

【 授权许可】

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