Directionality of residual stress evaluated by instrumented indentation testing using wedge indenter

• Published in: Metals and materials international Vol. 23; no. 3; pp. 465 - 472
• Main Authors: Ahn, Hee-Jun, Kim, Jong-hyoung, Xu, Huiwen, Lee, Junsang, Kim, Ju-Young, Kim, Young-Cheon, Kwon, Dongil
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.05.2017; Springer Nature B.V; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Engineering Thermodynamics; Hardness tests; Heat and Mass Transfer; Indentation; Indenters; Machines; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Metallic Materials; Processes; Residual stress; Solid Mechanics; Wedges; 재료공학; residual stress; metals; deformation; indentation; wedge indenter
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-017-6573-4

In instrumented indentation testing (IIT), residual stress can be evaluated by shift in indentation load-depth curves for stress-free and stressed states. Although the average surface residual stress is able to be evaluated with Vickers indenter, in order to know stress directionality, another indentation tests with two-fold symmetric indenter, for example, Knoop indenter, are needed. As some necessities for evaluating nonequibiaxial residual stress within small indent area, we suggest a novel way to evaluate directionality of residual stress, p , using wedge indenter characterized by two parameters, edge length and inclined angle. We develop wedge-indentation-mechanics model based on predetermined conversion factors which are determined by IITs for various uniaxial stressed states combining with finite element analysis simulations. By utilizing the developed model, directionality of residual stress is evaluated through two serial wedge IITs with respect to principal directions. We find good agreements between applied residual stress and residual stress evaluated by the developed model for biaxial tensile stress states.