Effect of substituting Mo for W on γ/γ′ partitioning behaviors of alloying elements in heat-treated second generation Ni based single crystal superalloys: An atom probe tomography study

The effect of substituting Mo for W on gamma/gamma ' partitioning behaviors of alloying elements in heat-treated second generation Ni based single crystal superalloys was investigated via atom probe tomography technique. Re, Cr, Co and Mo elements tended to distribute in gamma phase, while Al, Ta and W elements tended to distribute in gamma ' phase, and significant interfacial segregation was not found in experimental alloys. Moreover, substituting Mo for W obviously increased Re content in gamma phase. Meanwhile, Re content in gamma phase increased with increasing Mo + Cr content in single crystal superalloy, while Re content in gamma ' phase decreased with increasing W + Ta content in single crystal superalloy. In addition, partitioning ratios of both W and Mo elements were positively correlated with Ta content in single crystal superalloy, and partitioning ratio of Ta element was inversely correlated with Ta/Al ratio in single crystal superalloy. Furthermore, substituting Mo for W increased the solid solution strength of gamma phase but decreased the solid solution strength of gamma ' phase.

Automated summary

Substituting Mo for W increases Re content in the γ phase and solid solution strength, while decreasing Re content in the γ' phase with increasing W + Ta content. Partitioning ratios of W and Mo elements are positively correlated with Ta content, while the partitioning ratio of Ta is inversely correlated with Ta/Al ratio in single crystal superalloy.