Effect Of Elements On Hot Tearing Of Directionally Solidified Ni-Based Superalloys

The effect of elements such as Ti, Al, Hf, Zr and B on hot tearing susceptibility during directional solidification was explored by tube-like samples with thickness of 1.0 mm, 1.5mm and 2.0mm in wall. Results of SEM of elements on solidification of casting Ni-based superalloys were presented. The influential extent among the investigated elements is found to be: the largest is Ti, then Zr, B and Al, and Hf is the smallest. Titanium promotes the formation of (gamma+gamma') eutectic, increases sizes of the eutectic. Increasing Al content results in the size of gamma+gamma' eutectic and the number of gamma'. Increasing Zr content promotes gamma+gamma' eutectic.Varying B content shows little microstructural evolution.