Temperature dependence on γ/γ' partitioning behaviors of alloying elements and γ/γ' interfacial energy of a Mo-rich Ni based single crystal superalloy

Based on three-dimensional atom probe technique and Ardell method, the influences of temperature (850℃∼1150℃) on microstructure, compositions and solid solution strengths of γ and γ′ phases, γ/γ' partitioning behaviors of alloying elements and γ/γ' interfacial energy of a Mo-rich Ni based single crystal superalloy were investigated. After quenching from 1100℃, microstructure was basically similar as heat-treated state. However, after quenching from 1150℃, γ′ phase obviously re-dissolved, and γ channel obviously widened. Meanwhile, with increasing temperature, Co, Cr, Mo and Re contents in γ phase decreased, while Al and Ta contents in γ phase increased. With increasing temperature, Co, Cr and Re contents in γ′ phase slightly decreased, Mo content in γ′ phase significantly decreased, while Al and Ta contents in γ′ phase increased. Meanwhile, with increasing temperature, solid solution strength of γ phase decreased, while solid solution strength of γ′ phase increased. In addition, with increasing temperature, partitioning ratios of Co, Cr and Re elements decreased, partitioning ratios of Mo and Al elements increased, while partitioning ratio of Ta firstly decreased and then increased. Moreover, both γ/γ′ interfacial width and γ/γ′ interfacial energy decreased with increasing temperature.