The cliff-valley approach in the P-maps of PM/W joints for manufacturing the dual-alloys turbine disc

Abstract

In present work, hot deformation behavior of Ni-based dual-alloys has been investigated using processing map (P-map) at the temperatures of 1020-1140°C and strain rates of 0.001-1.0s-1. The processing map approach was further adopted to optimize hot forging process of dual-property turbine disc. Optimum processing condition is (Topi: 1140°C, ϵ opi: 1.0s-1) with the peak efficiency of 0.55 for processing dual-alloys. In addition, a new method to find the instability criterion (Cliff-Valley) from power dissipation map has been reported. The "cliff" and "valley" features are the sufficient condition of flow instability. The results indicate that P-map approach could be used to optimize the forging parameter for dual-alloys.