skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Statistical study of ductility-dip cracking induced plastic deformation in polycrystalline laser 3D printed Ni-based superalloy

Journal Article · · Scientific Reports
 [1];  [1];  [2];  [1]; ORCiD logo [3];  [1];  [1]
  1. Xi'an Jiaotong Univ. (China). State Key Lab. for Mechanical Behavior of Materials
  2. Xi'an Jiaotong Univ. (China). State Key Lab. for Manufacturing Systems Engineering
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source

Ductility-dip cracking in Ni-based superalloy, resulting from heat treatment, is known to cause disastrous failure, but its mechanism is still not completely clear. A statistical study of the cracking behavior as a function of crystal orientation in a laser 3D-printed DL125L Ni-based superalloy polycrystal is investigated here using the synchrotron X-ray microdiffraction. The dislocation slip system in each of the forty crystal grains adjacent to the 300 μm long crack has been analyzed through Laue diffraction peak shapes. In all these grains, edge-type geometrically necessary dislocations (GNDs) dominate, and their dislocation line directions are almost parallel to the crack plane. Based on Schmid's law, the equivalent uniaxial tensile force direction is revealed normal to the trace of the crack. A qualitative mechanism is thus proposed. Thermal tensile stress perpendicular to the laser scanning direction is elevated due to a significant temperature gradient, and thus locations in the materials where the thermal stress exceeds the yield stress undergo plastic deformation mediated by GND activations. As the dislocations slip inside the crystal grains and pile up at the grain boundaries, local strain/stress keeps increasing, until the materials in these regions fail to sustain further deformation, leading to voids formation and cracks propagation.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1379935
Journal Information:
Scientific Reports, Vol. 7, Issue 1; ISSN 2045-2322
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science

References (26)

Plastic deformation in Al (Cu) interconnects stressed by electromigration and studied by synchrotron polychromatic x-ray microdiffraction journal July 2008
Influences of phosphorus and sulphur on ductility dip cracking susceptibility in multipass weld metal of alloy 690 journal January 2012
Prevention of microcracking in dissimilar multipass welds of alloy 690 to type 316L stainless steel by Ce addition to filler metal journal August 2011
Residual stress preserved in quartz from the San Andreas Fault Observatory at Depth journal February 2015
Quantitative microstructural imaging by scanning Laue x-ray micro- and nanodiffraction journal June 2016
Effects of Boron on the Microstructure, Ductility-dip-cracking, and Tensile Properties for NiCrFe-7 Weld Metal journal December 2015
Frontiers of synchrotron research in materials science journal June 2016
Origin of stray grain formation in single-crystal superalloy weld pools from heat transfer and fluid flow modeling journal February 2010
Development of high-temperature strain instrumentation for in situ SEM evaluation of ductility dip cracking : HIGH-TEMPERATURE STRAIN INSTRUMENTATION FOR IN SITU SEM BY DDC journal April 2014
Cracking behavior and control of Rene 104 superalloy produced by direct laser fabrication journal November 2015
Electromigration-induced plastic deformation in passivated metal lines journal November 2002
In situ synchrotron study of electromigration induced grain rotations in Sn solder joints journal April 2016
Characterization of ion beam irradiated 304 stainless steel utilizing nanoindentation and Laue microdiffraction journal March 2015
A synchrotron study of defect and strain inhomogeneity in laser-assisted three-dimensionally-printed Ni-based superalloy journal November 2015
A dedicated superbend x-ray microdiffraction beamline for materials, geo-, and environmental sciences at the advanced light source journal March 2009
The influence of the laser scan strategy on grain structure and cracking behaviour in SLM powder-bed fabricated nickel superalloy journal December 2014
The influence of laser and powder defocusing characteristics on the surface quality in laser direct metal deposition journal March 2012
Effects of Filler Metal Composition on Inclusions and Inclusion Defects for ER NiCrFe-7 Weldments journal May 2013
A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy journal October 2015
Improving the ductility-dip cracking resistance of Ni-base alloys journal October 2006
Effect of substrate orientation on the columnar-to-equiaxed transition in laser surface remelted single crystal superalloys journal April 2015
High temperature behavior of Ni-base weld metal journal August 2004
Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys journal June 2016
High precision thermal stress study on flip chips by synchrotron polychromatic x-ray microdiffraction journal March 2010
High temperature behavior of Ni-base weld metal journal August 2004
A look-up table based approach to characterize crystal twinning for synchrotron X-ray Laue microdiffraction scans journal April 2015