Application of Other Models in the Measurement of Residual Stress
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The residual stress in a mechanically polished fused quartz beam was determined to verify the practicability of the Xu model (Xu and Li in Estimation of residual stresses from elastic recovery of nanoindentation 86:2835–2846, 2006 ). The used fused quartz is a common homogenous and isotropic amorphous material, with an elastic modulus of 72 GPa and Poisson’s ratio of 0.17. The fused quartz was manufactured into beam samples with the dimension of 70 mm × 13 mm × 5 mm. The fused beam was firmly held in a three-point bending (3 PB) device. The two supports of the bending device were fixed with an interval of 54 mm, and the load is applied by a micrometer with a displacement precision of 0.0254 mm. Nanoindentations were first performed at the end of the fused quartz beam outside the bending zone with a Berkovich indenter using a Hysitron Triboscope. Then the fused beam was strained to generate an applied stress field in the beam. Nanoindentations were subsequently made at the positions in the middle of the beam along the inside or outside edges where maximum bending compressive or tensile stresses occur. At least, five indents were made at each position with a constant peak indentation load of 990 μN.
KeywordsResidual Stresses Nanoindentation Isotropic Amorphous Material Berkovich Indenter Applied Stress Field