Improvement of Surface Properties of Nickel-Based Superalloys Grade Haynes 214 by Pack Aluminizing

Abstract

Abstract This research studied mechanical properties and oxidation resistance of Haynes 214 after pack aluminizing. The Haynes 214 samples were heat treated at various temperatures (973 K, 1073 K and 1173 K) for 1, 1.25, 4 and 6.25 hours, respectively. After aluminizing, there were two layers at the surface: the inner layer (Ni2Al3) located adjacent to Haynes 214 substrate and the outer layer (Ni2Al3 and NiAl3) at the surface. After aluminizing, surface hardness significantly increases from about 250 HV of substrate to more than 570 HV. With increasing hardness, wear resistance of aluminized samples can also be improved as can be seen from decreasing the specific wear rate from 2.24 × 10−6 g N−1m−1 to 7.6 × 10−7 g N−1m−1 after aluminizing. Cyclic oxidation tests of Haynes 214 with and without aluminizing show that both of them have good oxidation resistance due to slow growth rate of oxide film.