An alloy microstructure containing two distinct phases in roughly equal proportions, most commonly referring to duplex stainless steels which contain both austenite and ferrite. This dual structure provides a combination of high strength and excellent resistance to stress corrosion cracking. It requires precise control of cooling rates to maintain the balance between the two phases.
Heard on the job
We need to specify duplex stainless for the heat exchanger tubes to handle the high chloride environment.
Insider tip
Welding duplex alloys requires strict control of heat input to prevent the ferrite-austenite balance from shifting too far toward pure ferrite in the heat-affected zone.