Effect of non-isothermal aging treatments on the microstructure and properties of TiC-TiB2 ceramic particles-reinforced spray-formed 7055 aluminum alloy TIG weld metal.

Traditional isothermal aging treatments could not balance the relationship between mechanical properties and corrosion resistance of ultra-high-strength Al–Zn–Mg–Cu alloys. Therefore, the effect of non-isothermal aging (NIA) treatments on the microstructure and properties of TiC-TiB2 (BC) ceramic particles-reinforced spray-formed 7055 aluminum alloy tungsten inert gas (TIG) weld metal (WM) has been investigated. Weld joints were solid soluted at 475 °C for 2.5 h and quenched in water at 65 °C. Then, they were heated from 100 to 180 °C firstly at the rates of 60, 40, and 20 °C h−1 and cooled from 180 to 100 °C at the rate of 20 °C h−1. The results show that the mechanical properties of WM improve as the variable temperature rates decrease and its corrosion resistance deteriorates. The tensile strength of BC-20 is the best (580 ± 25 MPa), and the corrosion resistance of BC-60 is the best. The NIA treatments promote the formation of narrower precipitate free zones and finer-dispersed precipitates. Therefore, the mechanical properties (565 ± 25 MPa, 4.20 ± 0.21%) and corrosion resistance of BC-40 are excellent in the shorter aging time. [ABSTRACT FROM AUTHOR]