Superalloy is developed to meet the stringent requirements of materials used in aeroengine hot-end parts.It has become an irreplaceable key material for military and civil engines.With the increasing contents of Al an...Superalloy is developed to meet the stringent requirements of materials used in aeroengine hot-end parts.It has become an irreplaceable key material for military and civil engines.With the increasing contents of Al and Ti,the hot-working properties of superalloy materials are significantly reduced.The metallurgical technology and product quality of GH4720Li alloy produced by triple-melted process were introduced.The results showed that the PESR ingot structure was shrinkage-free,compact,and had high-degree purity,and the VAR process was obviously stable.The sulfur content of GH4720Li alloy was only several 10^(-6) by the triple-melted process,which was propitious for forging the alloy.The uniform heat treatment technology was also studied,and the results showed that the hot-working plasticity of GH4720Li alloy ingot was significantly improved after uniform heat treatment.The properties of GH4720Li alloy by the triple-melted process were good.展开更多
The hot deformation characteristics of GH4720Li alloy were studied at the temperature of 1 100--1 170 ℃ and strain rate of 0.01--1 s -1 using Gleeble hot compression tests. True stress-true strain curves and deformat...The hot deformation characteristics of GH4720Li alloy were studied at the temperature of 1 100--1 170 ℃ and strain rate of 0.01--1 s -1 using Gleeble hot compression tests. True stress-true strain curves and deformation microstructures were investigated. Constitutive equation was established using the hyperbolic law. Processing map for hot working was also developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. The results show that dynamic recrystallization is the dominant softening mechanism during hot deformation. Fully recrystallized grain is obtained at strain of 0. 7 above 1 130 ℃, and coarsening occurs above 1 150 ℃. The mean deformation activation energy is determined to be 512 kJ/mol. According to the low activation energy value, high dissipation efficiency parameter and fine recrystallized microstructure, 1 130 ℃ is chosen as the hot working temperature for GH4720Li alloy.展开更多
文摘Superalloy is developed to meet the stringent requirements of materials used in aeroengine hot-end parts.It has become an irreplaceable key material for military and civil engines.With the increasing contents of Al and Ti,the hot-working properties of superalloy materials are significantly reduced.The metallurgical technology and product quality of GH4720Li alloy produced by triple-melted process were introduced.The results showed that the PESR ingot structure was shrinkage-free,compact,and had high-degree purity,and the VAR process was obviously stable.The sulfur content of GH4720Li alloy was only several 10^(-6) by the triple-melted process,which was propitious for forging the alloy.The uniform heat treatment technology was also studied,and the results showed that the hot-working plasticity of GH4720Li alloy ingot was significantly improved after uniform heat treatment.The properties of GH4720Li alloy by the triple-melted process were good.
基金Item Sponsored by National Basic Research Programof China(2010CB631203)
文摘The hot deformation characteristics of GH4720Li alloy were studied at the temperature of 1 100--1 170 ℃ and strain rate of 0.01--1 s -1 using Gleeble hot compression tests. True stress-true strain curves and deformation microstructures were investigated. Constitutive equation was established using the hyperbolic law. Processing map for hot working was also developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. The results show that dynamic recrystallization is the dominant softening mechanism during hot deformation. Fully recrystallized grain is obtained at strain of 0. 7 above 1 130 ℃, and coarsening occurs above 1 150 ℃. The mean deformation activation energy is determined to be 512 kJ/mol. According to the low activation energy value, high dissipation efficiency parameter and fine recrystallized microstructure, 1 130 ℃ is chosen as the hot working temperature for GH4720Li alloy.
