To investigate the influence of W and Al on the microstructure and mechanical properties of a high-W superalloy,the Thermo-Calc calculation was utilized to simulate the microstructure with various W and Al contents.Th...To investigate the influence of W and Al on the microstructure and mechanical properties of a high-W superalloy,the Thermo-Calc calculation was utilized to simulate the microstructure with various W and Al contents.The results indicated that the concentration of W and Al exceeded 15.7 wt%and 5.9 wt%,respectively,the abnormal tungsten-richα-W phase would precipitate.Compared with the results of orthogonal experiment,the precipitation ofα-W phase is consistent with thermodynamic calculation results.The presence of Al not only influenced the precipitation ofα-W phase but also impacted the eutectic content and theγʹ-size,both of which showed an increase with higher Al concentrations.Excessive W and Al contents promoted the precipitation ofα-W phase,escalating the site of crack nucleation,and ultimately decreasing the plasticity.In the process of creep deformation(975℃/235 MPa),the raftedγ'phases were more continuous with increasing W contents,which increased the difficulty of dislocation climbing.As Al content increased,the density of interfacial dislocation network increased.The dislocations were entangled with each other,and the hindrance of dislocation movement was enhanced,which improved the stress rupture life.However,the precipitation of the hard and brittleα-W phase was attributed to the excessive W and Al,which increased the tendency of crack formation and significantly diminished the stress rupture life.The alloy exhibited the highest stress rupture life of 110.46 h when the W and Al contents were 15.7 wt%and 5.9 wt%,respectively.展开更多
基金financial support received from the National Key Research and Development Program of China(2022YFB3705000)the National Natural Science Foundation of China(No.52303394)the Liaoning Provincial Natural Science Foundation(No.2023-BS-015).
文摘To investigate the influence of W and Al on the microstructure and mechanical properties of a high-W superalloy,the Thermo-Calc calculation was utilized to simulate the microstructure with various W and Al contents.The results indicated that the concentration of W and Al exceeded 15.7 wt%and 5.9 wt%,respectively,the abnormal tungsten-richα-W phase would precipitate.Compared with the results of orthogonal experiment,the precipitation ofα-W phase is consistent with thermodynamic calculation results.The presence of Al not only influenced the precipitation ofα-W phase but also impacted the eutectic content and theγʹ-size,both of which showed an increase with higher Al concentrations.Excessive W and Al contents promoted the precipitation ofα-W phase,escalating the site of crack nucleation,and ultimately decreasing the plasticity.In the process of creep deformation(975℃/235 MPa),the raftedγ'phases were more continuous with increasing W contents,which increased the difficulty of dislocation climbing.As Al content increased,the density of interfacial dislocation network increased.The dislocations were entangled with each other,and the hindrance of dislocation movement was enhanced,which improved the stress rupture life.However,the precipitation of the hard and brittleα-W phase was attributed to the excessive W and Al,which increased the tendency of crack formation and significantly diminished the stress rupture life.The alloy exhibited the highest stress rupture life of 110.46 h when the W and Al contents were 15.7 wt%and 5.9 wt%,respectively.
