Modeling and characterization of as-welded microstructure of solid solution strengthened Ni-Cr-Fe alloys resistant to ductility-dip cracking Part II: Microstructure characterization

Author(s)

Unfried-Silgado, Jimy ^{[1, 2, 3]} ; Ramirez, Antonio J. ^[1]

Affiliation

^[1] CNPEM ABTLuS, Brazilian Nanotechnol Natl Lab, Met Characterizat & Proc Lab, Campinas, SP - Brazil

^[2] Univ Estadual Campinas, UNICAMP, Fac Engn Mecan FEM, Campinas, SP - Brazil

^[3] Univ Autonoma Caribe, Programa Ingn Mecan, Grp IMTEF, Barranquilla - Colombia

• Document type: Journal article
• Source: METALS AND MATERIALS INTERNATIONAL; v. 20, n. 2, p. 307-315, MAR 2014.
• Web of Science Citations: 2

Abstract

In part II of this work is evaluated the as-welded microstructure of Ni-Cr-Fe alloys, which were selected and modeled in part I. Detailed characterization of primary and secondary precipitates, subgrain and grain structures, partitioning, and grain boundary morphology were developed. Microstructural characterization was carried out using optical microscopy, SEM, TEM, EBSD, and XEDS techniques. These results were analyzed and compared to modeling results displaying a good agreement. The Hf additions produced the highest waviness of grain boundaries, which were related to distribution of Hf-rich carbonitrides. Experimental evidences about Mo distribution into crystal lattice have provided information about its possible role in ductility-dip cracking (DDC). Characterization results of studied alloys were analyzed and linked to their DDC resistance data aiming to establish relationships between as-welded microstructure and hot deformation performance. Wavy grain boundaries, primary carbides distribution, and strengthened crystal lattice are metallurgical characteristics related to high DDC resistance. (AU)

• FAPESP's process: 06/05661-1 - Study of intergranular fracture mechanism by ductility reduction in Ni-Cr-Fe alloys
• Grantee: Jimy Unfried Silgado
• Support Opportunities: Scholarships in Brazil - Doctorate