Fabrication of NiAl alloy hollow thin-walled component through hot gas forming of Ni/Al laminated tube and conversion process

Abstract

The NiAl intermetallic compounds have higher service temperature and lower density than traditional Ni-based super-alloy. In this work, for overcoming the fabricating bottleneck of NiAl alloy hollow thin-walled component, a typical NiAl alloy square-section component was obtained by hot gas forming of NiAl laminated tube and conversion. Firstly, the Ni/Al laminated tubes with tight interfacial bonding between layers and considerable plasticity was prepared by controlling the thickness and distribution of intermediate layer (NiAl3 and Ni2Al3). Then, the hot gas forming behavior and micro-damage control method of the Ni/Al laminated square-section component were studied under different process parameters. Finally, the Ni/Al laminated square-section components were converted into NiAl alloy components at 1200 °C/1 h. The results show that the forming temperature and gas pressure loading rate are the key parameters for hot gas forming of Ni/Al laminated materials. At an optimal temperature, the micro-damage can be avoided and the fillet accuracy can be controlled by adjusting the strain rate through using different gas pressure loading rates.

Keywords

• NiAl alloy
• Conversion
• Hollow thin-walled component
• Hot gas forming
• Microstructure and property