Residual stress measurement across the scales

Residual stresses are unavoidable in heat treatment and surface engineering and their presence can be advantageous or disastrous for the performance of components. Residual stresses cannot be measured directly, but are determined from strain measurements, either non-destructively from diffraction-based methods, or destructively from relaxation-based methods. In this presentation, three examples of stress determination from strain measurements showcase some of the possibilities:

• Phase-specific stresses in austenite and martensite during thermal martensite formation in a soft martensitic stainless steel [1];
• Phase-specific stresses in austenite and martensite during strain-induced martensitic transformation of reverted austenite during in-situ loading in a super martensitic stainless steel [2];
• Residual stress in Zr,Cu-based bulk metallic glass surface-engineered by internal oxidation [3].

For the first two topics energy dispersive synchrotron X-ray diffraction was used to enable in-situ analysis. For the third topic, the results obtained with laboratory scale X-ray diffraction and ring-core milling with focused-ion beam and digital image correlation are compared.

[1] M. Villa, F. Niessen, M.A.J. Somers, Metall. Mater. Trans. A 49 (2018) 28–40.

[2] F. Niessen, A.A. Gazder, J. Hald, M.A.J. Somers, Acta Mater. 220 (2021) 117339

[3] S. Haratian, F. Niessen, F.B. Grumsen, M.J. Nancarrow, E.V. Pereloma, M. Villa,

T.L. Christiansen, M.A.J. Somers, Acta Mater. 200 (2020) 674-685

Keywords: residual stress; martensite; ring-core milling

Topic: Residual stress measurement