Transient liquid phase (TLP) bonding of nickel based alloys by forming an aluminum-titanium coating and subsequent heat treatment

摘要

Certain aspects of the invention provides a transient liquid phase (TLP) bonding structure, including Ni based alloys and a TLP bonded layer formed by pack cementation on the Ni based alloys using a pack composition. In one embodiment, the pack composition includes 57 wt. % of aluminum oxide powder, 30 wt. % of Ti powder, 10 wt. % of Ni-50 wt. % Al alloy powder and 3 wt. % of ammonium chloride powder. The Ni based alloys may be Ni-20 wt. % Cr alloys. In certain embodiments, pack cementation is performed on the Ni based alloys under argon for an hour using the pack composition to form a coating. Then the structure is sonicated in acetone for 2 hours, and then annealed under vacuum at about 1200° C. for 2 days to form the TLP bonding structure, which has a uniform γ′ phase distribution with identical compositions and properties at its bonding regions.