Microstructure evolution of an Ni-Cr-Co base superalloy heat-treated at 704 and 760℃

作     者：ZHAOShuangqun XIEXishan ZHAO Shuangqun and XIE Xishan1) High Temperature Materials Research Laboratories, University of Science and Technology Beijing, Beijing 100083, China2) Department of Physics, Ningxia University, Yinchuan 750021, China

作者机构：HighTemperatureMaterialsResearchlaboratoriesUniversityofScienceandTechnologyBeijingBeijing100083China；DepartmentofPhysicsNingxiaUniversityYinchuan750021China HighTemperatureMaterialsResearchLaboratoriesUniversityofScienceandTechnologyBeijingBeiiing100083China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2003年第22卷第3期

页      面：169-174页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

主　　题：Ni-Cr-Co base superalloy thermodynamic calculation microstructuralstability precipitate phase analysis 

摘      要：Thermodynamic calculation, SEM (scanning electron microscopy), TEM(transmission electron microscopy), XRD (X-ray diffraction), phase extraction, and chemical analysiswere employed to study the phase stability and phase precipitation in a new Ni-Cr-Co basesuperalloy heat-treated at 704 and 760 ℃ for a long tune. The results show that the precipitates ofthis new alloy heat-treated at standard annealing condition and heat-treated at 704 and 760℃ for atime up to 2000 h are γ′, MC, M_(23)C_6, and M_6C, and η phase forms at grain boundaries and inmatrix of samples heat-treated at 760 ℃ as well. The mass fractions of γ′ (+η), MC, M_(23)C_6,and M_6C in all samples have no large changes with an increase in aging time, but γ′ precipitatesgrow obviously. The γ′-to-η transformation in the samples heat-treated at 760℃ took place withincreasing aging time. The η precipitates form a Widmanstaetten pattern and the γ′ phases haveremelted partly in the samples heat-treated at 760 ℃. The alloy maintains a better microstructuralstability during prolonged aging at 704 ℃, but a worse microstructural stability during prolongedaging at 760 ℃.