Numerical simulation and prediction of solidification structure and mechanical property of a superalloy turbine blade

A Ni-based superalloy gas turbine blade was chosen as the test casting. The grain size, secondary dendrite arm spacing and Vickers hardness of the blade casting were simulated and also measured by using a software package. The comparison indicates that there is a good agreement between the results simulated and the results measured. By varying the casting conditions, the calculated results show that with the decrease of pouring temperature the grain size and the secondary dendrite arm spacing decrease and the hardness increases. With the increase of the preheated mould temperature, the grain size and the secondary dendrite arm spacing increase and the hardness decreases. However, with a higher preheated mould temperature the grain size in the blade would be more uniform. This indicates that numerical simulation offers a useful tool for predicting solidification structures and mechanical properties of gas turbine blade castings.