Congenerous and heterogeneous brazing of porous FeAl intermetallics

Abstract

Congenerous and heterogeneous brazing of porous FeAl intermetallics has been successfully realised using Cu–10Sn green compact as brazing filler. Cu–Sn intermetallic phases combined with (Cu,Sn) solid solution were formed in the brazing line for congenerous brazing, while (Cu,Sn) solid solution was the main phase formed for heterogeneous brazing. Maximum tensile strengths for congenerous and heterogeneous brazing are 75·0 and 83·9 MPa which are about 81·5 and 91·2% of that of porous FeAl alloy (∼92·0 Mpa) respectively. The interface structure of the stainless steel and porous FeAl joint brazed at 940°C for 15 min is S–S+(Cu,Sn)/(Cu,Sn)/Cu₉Al₄+(Cu,Fe)+(Cu,Sn)/AlFe₃+Al₄Cu₉+(Cu,Sn). In the porous FeAl and porous FeAl joint brazed with Cu–10Sn filler at 940°C, Cu–Sn intermetallics and (Cu,Sn) solid solution were the main phases in the joint line.

Keywords:

• Iron aluminides (based on FeAl)
• Brazing
• Mechanical properties
• Diffusion

The authors are grateful for the financial support from the 111 Project of Chinese Ministry of Education, NSF of China (grant nos. 2006AA03Z511, 50825102, 50721003 and 20636020) and the US Department of Energy with subcontract to Oak Ridge National Laboratory (no. DE‐AC05‐000R‐22725).