The influence of multi-axis forging and heat treatment on structure and mecanical properties of nickel-iron superalloy
The comparative analyses of structure, mechanical properties and fracture surfaces of ultrafine grained Inconel 718 obtained by multiple isothermal forging were performed. The refinement of structure down to 80 nm via multiple forging resulted in the strength increase and decrease in room temperature plasticity. After heat treatment this alloy (d=4 mm) had gained ultimate tensile strength of about 1520 MPa that is 15% higher than that of coarse grained alloy. Room temperature fatigue test for 10 <sup>5 </sup>cycles revealed the rise of the durability of heat treated condition by 1.7 times as compared to coarse grained alloy.