An X-ray study of residual stresses and bending stresses in free-standing Nb/Nb5Si3 microlaminates

Abstract Asymmetric X-ray diffraction was used to quantify residual stresses in Nb/Nb5Si3 microlaminates that were sputter deposited and then annealed at 1200°C for 3 h. The residual stresses are attributed to a mismatch in the thermal expansion coefficients for the Nb and Nb5Si3 phases, and can rise as high as 300 MPa on cooling from 1200°C. Sizable ( >500 MPa ) bending stresses were also detected in microlaminates that were curved after annealing and then were flattened for X-ray analysis. The residual stresses in the Nb laminates were quantified using an improved anisotropic elastic analysis that accounts for the strong 〈110〉 texture in these layers. The stresses in the Nb5Si3 laminates were quantified using an isotropic elastic analysis that accounts for both residual stresses and bending stresses.