Papers by Author: Jia Rong Li

Abstract: The creep and microstructures of DD6 single crystal superalloy with [001] orientation at 760°C and 785MPa were investigated. The results show that large a/2 dislocations are spread and concentrated in matrix channels during incubation period, and few of stacking faults are observed at later stage of incubation period. The stage of primary creep is characterized by the stacking faults shearing γ' phases, and the density of a/2 dislocations in the matrix continues to increase. The density of the stacking faults increases during the stages of secondary and tertiary creep.

Abstract: 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 (γ+γ´) eutectic, increases sizes of the eutectic. Increasing Al content results in the size of γ+γ´ eutectic and the number of γ´. Increasing Zr content promotes γ+γ´ eutectic.Varying B content shows little microstructural evolution.