Solution Heat Treatment of Single Crystal Superalloy with Electric Field

摘要

The effect of a DC electric field on solution heat treatment of Ni-based single crystal superalloy DD3 was investigated by means of optical metallograph, scanning electron micrograph (SEM) and electron probe microanalysis (EPMA). The superalloy samples were heat-treated at 1220, 1230, 1240 and 1250"C for four hours under the electric field E= 1000 V/cm, respectively. The experimental results showed that: a) the electric field solution heat treatment (EFSHT) enhanced microstructure homogenization; b) the distributions of alloy elements, especially the refractory metal elements Mo and W, were more homogeneous after EFSHT; and c) EFSHT enhanced dissolution and reduced-solvus temperature. The likely mechanism was that the electric field enhanced the migration of the vacancies from the interior to the surface, which increased the diffusion rate of atoms.