Effect of thermal aging on mechanical properties and microstructural development of Hastelloy C and C276

Hastelloy C and Hastelloy C276 are Ni-based alloys commonly used in applications where corrosion resistance and high temperature performance are required. The alloys are similar in composition, with Hastelloy C276 having a lower impurity content, making it more attractive for welding applications. The current effort focused on effects of low to moderate temperature (200-600˚C), short duration (100-1000 hours) thermal aging on microstructural evolution and mechanical properties of the Hastelloy C alloy and low temperature (200-400˚ C), longer duration (decades) aging of Hastelloy C276. Evolution of precipitates, grain structure, and hardness as a function of thermal aging was studied, including comparisons between microstructural evolution resulting from composition differences of C and C276. Room and elevated temperature mechanical properties of both aged and unaged specimens will also be presented.

Sandia National Laboratories is a multimission Laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.