Effect of austenite stability on mechanical properties of alloys strengthened by thermo-mechanical treatment and aging

The mechanical properties are studied of stainless austenitic alloys strengthened by thermo-mechanical treatment with subsequent ageing, in which development of martensitic γ → α transformation is possible in the course of plastic deformation during the testing of mechanical properties. The indicated alloys differ only in their nickel content. As the latter decreases, the ultimate strength increases, while the yield limit reduces. After ageing for 1 hour at 700 deg C, alloys with 20, 18, and 15% Ni have a yield limit of 120, 115, and 100kgf/mm2, respectively