Recycled Applications of a Single Crystal Superalloy

Abstract

The effects of application of recycled scraps on the composition, microstructure and mechanical properties of SRR99 alloy were studied. The compositions of recycle master alloy are similar to that of the fresh alloy. However, nitrogen content, the size and amount of microporosity increase significantly with the recycle material proportion. Granular, lamellar and strip-like MC particles mainly represent in the interdendritic regions of the revert alloy. With the addition of the recycled material proportion, the amount of the granular ones rapidly drop and the lamellar ones gently enhance. The stress rupture life decline with the addition of the recycled material proportion. The oxide and sulphide inclusions in revert superalloy can be effectively captured and removed by a foam ceramic filter so that the tensile and stress rupture property has been significantly improved.

Nitrogen-Bearing Carbides in K417G Alloy Doped with Different Nitrogen Contents

“…Previous studies of nitrogen in superalloys mainly focused on the re-used or the recycled superalloys, little studies about nitrogen or carbonitrides were done on the virgin materials [9][10][11]. The paper mentioned that the root of the nitrogen problem in the superalloys stemed from the insolubility of nitrogen in the primary gamma phase, corresponding to the low solubility of nitrogen in solid nickel [4].…”