Diffraction Measurement of Residual Stresses on Components of Varying Complexity Aimed at Steering the Development of Process Modelling Efforts.
Dr. Don W. Brown
Los Alamos National Laboratory,
Los Alamos, New Mexico.
Additive manufacture (AM) refers to the process of “growing” parts to near net shape from the ground up through deposition of molten material from either powder or wire feed, in contrast to the more traditional subtractive techniques where material is removed from cast or wrought billets. Common to all of the myriad AM techniques that are currently used for metals are strong thermal gradients and rapid quenching of the deposited material. These necessarily result in large, often yield-level, residual stresses in the as-deposited part which can result in large-scale distortions. Test objects of varying levels of complexity, from simple line depositions to complex net-shape components have been manufactured. Diffraction measurements of residual stress were completed with the stated purpose of providing input and/or validation data to aid process model development. For instance, simple single and double line depositions were studied to see if models could predict the difference between the start and stop end in a single line scan, and/or the difference between the start/stop and turn-around end in a double line scan. On the other end of the complexity spectrum, a component with complex geometry including multiple bore holes in different orientations was measured for validation of a process model. The technique of diffraction measurement of stress will be presented as well as results from the various test objects including comparison to model results.
Date(s) - 02/22/2018
4:00 pm - 5:00 pm
1062 Bainer Classroom
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