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

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

“…The processes and their effects on materials were also subjected to tremendous research efforts to understand the connection and interaction between processing, microstructure and mechanical properties. For accurate metallurgical understanding and description of the underlying phenomena, new tools for materials analysis, such as dilatometry [48,49], scanning electron microscopy [39,[50][51][52][53], transmission electron microscopy [54][55][56], X-ray diffraction [57][58][59] and software for thermodynamics, thermal and mechanical behavior [60], have been developed and are now extensively used by both academia and industry.…”

Effects of Alloying Elements on the Stacking Fault Energies of Ni58Cr32Fe10 Alloys: A First-Principle Study

“…During a deformation process, low SFE materials could achieve a more homogeneous distribution of dislocations and facilitate more homogeneous deformed microstructures compared with high SFE materials. The homogeneous deformation process means better DDC resistance [11][12][13][14]. On the basis of our simulation, the addition of Nb significantly decreases the SFE at room temperature.…”

“…It is commonly known the following reasons could associate with DDC in the Alloy 690 weld joints: grain size, grain boundary migration, grain boundary segregation, precipitation behavior, chemical composition, and so forth [1][2][3][4][5][6]. Recent studies revealed that DDC resistance of Alloy 690 weld joints could be improved by tailoring the stacking fault energy (SFE) [11][12][13][14].…”

“…As a consequence, the recombination process in low SFE materials is harder than that in high SFE materials. This condition leads to a more homogeneous distribution of dislocations and facilitates more homogeneous deformed microstructures compared with high SFE materials [11][12][13][14]. It should be pointed out that decreasing the SFE may not increase the global ductility (or macro ductility), but could potentially lead to a more homogeneous distribution of dislocations.…”

Characterization of complex carbide–silicide precipitates in a Ni–Cr–Mo–Fe–Si alloy modified by welding

“…Although there have been some detailed studies of the nature of the precipitates and their stability after heat treatment [7,[15][16][17], very few in-depth studies appear in the literature characterizing different types of precipitates in different weldment regions of this type of alloy. In the study by Ojo et al [18], the authors characterize the microstructure of dendrites and precipitates in the weld fusion zone of IN 738LC alloy, while Unfried-Silgado et al also focuses their attention on the microstructure of matrix and precipitates in the welded zone of Ni-Cr-Fe alloy with and without Mo additions [19] In this paper, the authors have attempted to characterize the precipitates as they appear in various locations in the welded sample, such as the HAZ or weld metal, using advanced sampling techniques such as focussed ion beam (FIB) milling to extract site-specific samples for transmission electron microscopy (TEM). The information thus obtained has been complemented with advanced characterization techniques such as high-resolution energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) to gain a deeper insight into the evolution of these precipitates as a function of the maximum local temperature reached during welding.…”