Using X-rays to Validate the Next-Generation of Thermo-Mechanical Processing Codes

Darren Pagan, Staff Scientist, CHESS

Additive manufacturing or ‘3-D Printing’ of metallic alloys promises to revolutionize manufacturing with its ability to eliminate waste, enable the production of parts with complex shapes previously not possible, allow replacement parts to be built in remote environments (e.g. at sea or in space), and reduce the costs of creating replacement parts for legacy equipment.

Dispersive diffraction data

Schematic of the use of the energy dispersive diffraction data to valid predictions from the thermo-mechanical processing code, Diablo.

Before this is all possible, additively manufactured parts must be created with microstructures and compositions comparable to their traditionally manufactured counterparts in order to ensure the same required performance and safety integrity. One of the most-pressing problems that arises in the additive manufacturing process is the development of residual stresses.  These stresses that develop during rapid cooling essentially ‘spring-load’ a part before it is placed in service and can lead to premature failure. To reduce the prevalence of these unwanted stresses, new thermo-mechanical models must be developed to significantly improve the build process, but before these models can be put to use, they must be tested and calibrated with high-fidelity experimental data. Recent published experimental results from the A2 station at CHESS by a team from Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and the National Institute for Standards and Technology (NIST) have used the polychromatic energy dispersive diffraction technique to characterize the residual strains and stresses in specially designed bridge components made from the work-horse aerospace alloy Ti-6Al-4V. Critically, the results served as a validation for a major, large-scale thermo-mechanical additive manufacturing simulation code (Diablo) developed at LLNL that can now move forward towards developing new build strategies for optimized additively manufactured parts.

 

Collaborators:

Strantza, M, Los Alamos National Laboratory

Ganeriwala, RK, Lawrence Livermore National Laboratory

Clausen, B, Los Alamos National Laboratory

Phan, TQ, National Institute of Standards and Technology

Levine, LE, National Institute of Standards and Technology

Pagan, D, Cornell High Energy Synchrotron Source

King, WE Lawrence Livermore National Laboratory

Hodge, NE, Lawrence Livermore National Laboratory

Brown, DW, Los Alamos National Laboratory

 

Publication citation:

Strantza, M., Ganeriwala, R.K., Clausen, B., Phan T.Q., Levine L.E., Pagan, D., King, W.E., Hodge N.E., Brown D.W., Coupled experimental and computational study of residual stresses in additively manufactured Ti-6AI-4V components.  Materials Letters, 231, 221-224, doi.org/10.1016/j.matlet.2018.07.141, November 15, 2018

 

Funding:

Funding Agency Grant Number
U.S. Department of Energy by Los Alamos National Laboratory 

DE-AC52-06NA25396 
Lawrence Livermore National Laboratory 

DE-AC52-07NA27344 
National Science Foundation 

DMR-1332208