Effect of cold work on precipitation behavior of Ni Span C902 Super alloy

In this study, the influence of cold work on precipitation behavior in Ni Span C902 super alloy is considered to investigate. The samples were homogenized at 1000 ᵒC, and then samples were subjected to different amount of cold work of 30, 40 and 60%. Precipitation hardening treatments were performed at 450, 550, 650 and 750 ᵒC for 1 to 6 hours. Microstructural observations were done by optical microscope and precipitation hardening behaviors were investigated by Vickers hardening test. The results indicated that precipitation hardening at the temperatures of 450 and 550 ᵒC could not provide proper conditions for formation of strengthening precipitations (γ´); while hardness increased significantly by increasing the aging temperature. The maximum hardness has been achieved for the homogenized and the 60% cold worked samples at 750 and 650 ᵒC, respectively. The results of empirical observations of the experiments in the present study are in well consistent in comparing to Johnson-Mehl-Avrami equations.