The fundamental mechanism of the cracking formation was investigated for the as-cast GH4151 superalloy.By analyzing the characteristics of cracking,the cracking mechanism was determined to be the cold crack formed dur...The fundamental mechanism of the cracking formation was investigated for the as-cast GH4151 superalloy.By analyzing the characteristics of cracking,the cracking mechanism was determined to be the cold crack formed during the cooling process.And cold cracking is closely related to severe segregation,complex precipitates and uneven γ'phase distribution.During cooling process,cracks were generated around the precipitates due to their different linear shrinkage coefficients.The annealing treatment process controlling the residual stress,the size and morphology of γ'phase was proposed.The annealing treatment plays a role in reducing residual stress through decreasing the thermal gradient and controlling the size distribution of γ'phase to reduce the strain concentration around the precipitate phases.展开更多
Based on XRD,SEM and EDS analyses,the phases in GH4151 alloy were identified.Differential scanning calorimetry(DSC)experiment and metallographic method were carried out to determine the incipient melting temperature(I...Based on XRD,SEM and EDS analyses,the phases in GH4151 alloy were identified.Differential scanning calorimetry(DSC)experiment and metallographic method were carried out to determine the incipient melting temperature(IMT)of the alloy.The result shows that the IMT of alloy is situated between 1150 and 1160℃.Subsequently,the dissolution process of Laves phase was carried out,and the dissolution kinetic equations were obtained at different temperatures.And then based on the verification of experiments,the model was confirmed to be credible to predict the fraction of the Laves phase dissolution.Finally,the results of diffusion coefficients indicate that the diffusion of Nb element is a critical factor for homogenization process of GH4151 alloy.展开更多
基金Project(50974016)supported by the National Natural Science Foundation of China。
文摘The fundamental mechanism of the cracking formation was investigated for the as-cast GH4151 superalloy.By analyzing the characteristics of cracking,the cracking mechanism was determined to be the cold crack formed during the cooling process.And cold cracking is closely related to severe segregation,complex precipitates and uneven γ'phase distribution.During cooling process,cracks were generated around the precipitates due to their different linear shrinkage coefficients.The annealing treatment process controlling the residual stress,the size and morphology of γ'phase was proposed.The annealing treatment plays a role in reducing residual stress through decreasing the thermal gradient and controlling the size distribution of γ'phase to reduce the strain concentration around the precipitate phases.
基金Project(50974016)supported by the National Natural Science Foundation of China。
文摘Based on XRD,SEM and EDS analyses,the phases in GH4151 alloy were identified.Differential scanning calorimetry(DSC)experiment and metallographic method were carried out to determine the incipient melting temperature(IMT)of the alloy.The result shows that the IMT of alloy is situated between 1150 and 1160℃.Subsequently,the dissolution process of Laves phase was carried out,and the dissolution kinetic equations were obtained at different temperatures.And then based on the verification of experiments,the model was confirmed to be credible to predict the fraction of the Laves phase dissolution.Finally,the results of diffusion coefficients indicate that the diffusion of Nb element is a critical factor for homogenization process of GH4151 alloy.
