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

Asymmetric X-ray diffraction was used to quantify residual stresses in Nb/N b5Si3 microlaminates that were sputter deposited and then annealed at 1200 degrees C for 3 h. The residual stresses are attributed to a mismatch in th e thermal expansion coefficients for the Nb and Nb5Si3 phases, and can rise as high as 300 MPa on cooling from 1200 degrees C. Sizable (> 500 MPa) ben ding stresses were also detected in microlaminates that were curved after a nnealing and then were flattened for X-ray analysis. The residual stresses in the Nb laminates were quantified using an improved anisotropic elastic a nalysis that accounts for the strong [110] texture in these layers. The str esses in the Nb5Si3 laminates were quantified using an isotropic elastic an alysis that accounts for both residual stresses and bending stresses. (C) 2 000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights re served.