A new alloy developed by Carpenter Technology Corp., Wyomissing, PA, USA, is Carpenter AerMet® 340 alloy, the latest in the company’s AerMet series of ultra high strength and ultra high toughness alloys.
Carpenter AerMet 340 offers high hardness (HRC 56), 345 ksi (2379 MPa) ultimate tensile strength (UTS), exceptional fracture toughness of 34 ksi√in (37MPa√M), and yield strength (YS) of 300 ksi (2068 MPa). The new alloy has demonstrated superior ductility to alloys of similar strength in terms of an elongation of 11% and reduction in area (RA) of 53%. It has also demonstrated fatigue strength of 140 ksi (965 MPa) at runout in rotating bending fatigue stress tests. Typical mechanical properties are shown in Table 1.
Carpenter AerMet® 340 alloy exhibits strength and toughness comparable to that of Marage 350 but with substantially improved ductility and fatigue resistance.
The new Carpenter grade can be considered for a variety of automotive, racing, aerospace and defense. Applications have included tubing, structural parts and components, drive shafts, springs, connecting rods and crank shafts.
The new Carpenter alloy is a precipitation hardenable (PH) martensitic grade that is heat treated and typically aged at about 900°F (482°C) to develop the desired properties. It is available from Carpenter in bar, hollow bar, sheet, wire, billet, plate and strip.