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

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.