ATI Nitinol: Production and Properties

ATI’s Wah Chang Business Unit is a major producer of nickel titanium shape memory alloys, also known as Nitinol. In the Aerospace industry, Nitinol fluid fittings have been in service in commercial and military applications for a number of years with the advantages being light weight, compact, and leak free service. Recently interest is increasing for SMA aerospace actuators, particularly warm binary Nitinol with austenite start temperatures greater than 75°C and ternary alloys, such as NiTiHf, with austenite start temperatures greater than 200°C. This increasing interest is driven by weight saving by use of a compact SMA actuator compared to traditional hydraulic and electric actuator systems. The production of Nitinol alloys follows a similar process to that used for other common alloy systems, but has unique challenges and characteristics. This presentation will show an outline of the process for taking the elemental components and producing Nitinol products at ATI. The presentation will also discuss selected material properties relevant for Nitinol actuators, such as transformation temperatures and non-metallic inclusion size and frequency.