Welding trials of new Aubert & Duval Nickel Alloy, AD730®

Aubert & Duval designed the new nickel alloy AD730® in response to the need for metals that can function at high temperatures in fields such as aerospace, energy, and automotive industry.

Advanced creep and fatigue properties, as well as microstructural stability at elevated temperatures are the key.

AD730® is a fully-innovative cast & wrought nickel-based superalloy that withstands high temperatures (750°C/1382°F) while preserving strength, creep and fatigue resistance at a competitive cost.

While AD730 has high functioning tensile, creep, and fatigue properties, the large amount of alloying elements mean that nickel alloys can be difficult to weld.

TWI were called to investigate how the new alloy held up under three different welding processes – Mechanised TIG Welding, Electron Beam Welding, and Linear Friction Welding.

These first welding trials on AD730® proved that it is fairly weldable due to the tested mechanical properties and microstructure not being altered to a critical extent. TIG welds showed no obvious brittle phases that would systematically lead to cracking and a reasonable range of parameters could be used to weld

With the processes investigated, no drastic decrease in mechanical properties was observed, creating a base from which further research can be conducted, according to application, to find the best processes for use by Aubert & Duval’s clients.