RESIDUAL STRESSES IN AN INCONEL-718-CLAD TUNGSTEN TUBE PROCESSED BY HOT ISO-STATIC PRESSING

We have completed a comparative X-ray diffraction (XRD) and Finite Element Analysis (FEA) study of Inconel 718 clad Tungsten tubes, of relevance to the Accelerator Production of Tritium (APT) program at the Los Alamos National Laboratory (LANL). Because the Inconel cladding must be in intimate contact with the tungsten at operating temperatures, the materials are diffusion bonded by Hot Iso-static Pressing (HIP) at 1080°C. However, the difference in thermal expansion coefficients of inconel 718 and tungsten produce large residual stresses upon cooling. The classical XRD (d vs. sin 2 ψ) technique was used to determine the stresses in the outer layer of inconel 718. These results are used to benchmark Finite Element Analysis (FEA) calculations, and a direct comparison is made in this paper.