Article: Park, JS; Yildizli, K; Demir, E; Dawson, PR; Miller, MP; “Non-Destructive Characterization of Subsurface Residual Stress Fields and Correlation with Microstructural Conditions in a Shot-Peened Inconel Component”, Experimental Mechanics, 58 (9): 1389-1406
Abstract: Shot-peening is an important surface treatment used in a preventative way to guard against fatigue failures. The residual stress state imparted by shot-peening deters the formation and propagation of surface cracks. In this paper, we describe the measurement of residual stresses in an Inconel, IN100, sample using lattice strains measured using High Energy X-ray Diffraction (HEXD) and a Bi-Scale Optimization Method (BSOM). HEXD enabled rapid, non-destructive lattice strain measurements over a large region of the sample. Subsurface strains were obtained using a conical slit setup. The BSOM utilizes a macroscale representation of the sample and a spherical harmonic-based crystal scale representation of crystal orientation space at each experimental point (diffraction volume). A roughly biaxial stress state was predicted with a von Mises equivalent stress between 300 MPa and 400 MPa near the surface. The layer of material with high residual stress induced by shot-peening was found to be approximately 1 mm thick. Diffraction peak width, EBSD, and microhardness measurements were also made on the same sample, which rendered more qualitative measures of the plasticity-related effects of the shot-peening induced residual stress field. All of these measurements show a dimishing shot-peening plasticity with the increasing depth.
Funding Acknowledgement: US Air Force Office of Scientific Research [FA9550-09-1-0642]; DOE Office of Science by Argonne National Laboratory [DE-AC02-06CH11357]; National Science Foundation Materials Research Science and Engineering Centers program [DMR-1120296]
Funding Text: Dr. Ulrich Lienert,8 formerly of the APS, is strongly acknowledged for his assistance and expertise in the conduction of the diffraction experiments and the data collection. Dr. Jay Schuren,9 formerly of the US Air Force Research Laboratory, is acknowledged for his work on the data reduction algorithms and inversion scheme. Dr. Kemal Yildizli worked as Post Doctoral Fellow by the Scientific and Technological Research Council of Turkey (TUBITAK) 2219 Scholar in this work. Dr. Dennis Buchanan, Dr. Reji John, and Dr. T.J Turner, of the US Air Force Research Laboratory, are acknowledged for providing the shot-peened sample. Mr. Donald Boyce, formerly of the Deformation Processes Laboratory at Cornell University, is acknowledged for his assistance with the generation of the spherical harmonic functions. This work has been supported financially by the US Air Force Office of Scientific Research and program director Dr. David Stargell under Grant No. FA9550-09-1-0642. This research u sed resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This work made use of the Cornell Center for Materials Research Shared Facilities which are supported through the National Science Foundation Materials Research Science and Engineering Centers program (DMR-1120296). The data set associated with this work is available through the Materials Data Facility (https://www.materialsdatafacility.org/) at https://doi.org/10.18126/M2NM0B.