材料期刊网

研究了一种新型高强抗热腐蚀DZ68合金,运用低偏析技术设计了DZ68合金的成分,利用OM,SEM和XRD等研究了DZ68合金铸态、热处理态的微观组织.研究了DZ68合金拉伸.持久性能和抗热腐蚀性能,并与DZ125和IN738合金进行了比较.结果表明:铸态DZ68合金组织由,γ,γ',(γ+γ')共晶、MC型碳化物和少量硼化物组成,热处理后的组织由γ,γ',MC和M_(23)C_6型碳化物组成;DZ68合金的拉伸性能和持久性能与DZ125合金相当,抗热腐蚀性能与IN738合金相当,并具有良好的组织稳定性.

In order to meet the requirements of marine gas turbine blade materials, a new-type directional solidification Ni-based superalloy named DZ68 was developed. The alloy composition was designed by low segregation technology. Its nominal chemical composition (mass fraction, %) is C 0.05, Cr 12.0, Mo 1.0, W 5.0, Co 8.5, Al 5.3, Ti 0.5, Ta 5.0, Re 2.0, B 0.01, and balance is Ni. The microstructures of as-cast DZ68 alloy and after heat treatment states were analyzed by OM, SEM and XRD. The tensile, rupture and hot corrosion resistance properties of DZ68 alloy were compared with DZ125 and IN738 alloys. Results show that the microstructure of as-cast DZ68 alloy is composed of γ,γ', (γ+γ') eutectics, MC type carbides and a few borides. After heat treatment, the microstructure of DZ68 alloy is composed of γ,γ' and carbides. The carbides are mainly MC and M_(23)C_6. The tensile strength of DZ68 alloy decreases slightly with the increase of temperature, and reaches its minimum value at 700 ℃. When the temperature is higher than 700 ℃, the tensile strength increases so evidently that reaches its maximum at once at 760 ℃, But when the temperature is higher than 760 ℃ its tensile strength decreases obviously. It is well recognized the relationship of the tensile strength of DZ68 alloy with temperature is abnormal, similar to that of its yield strength but opposite to that of its plasticity. The tensile and rupture properties of DZ68 alloy are nearly the same as those of DZ125 alloy and its hot corrosion resistance property is nearly the same as that of IN738 alloy under the same conditions.