Characterization of γ′ precipitates in a nickel base superalloy quenching from aging temperature at different rates  

作　　者：LI Hongyu, SONG Xiping, WANG Yanli, and CHEN Guoliang State Key Lab for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China 

出　　处：《Rare Metals》2010年第2期204-208,共5页稀有金属（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 50471097)

摘　　要：The characteristics of γ′ precipitates in a superalloy quenched from 1050°C at different rates were investigated using field emission scanning electron microscope（FESEM）.When quenched from 1050°C, the size of primary aging γ′ precipitates has a small increase in the specimens that experienced iced-brine-quenching, oil-quenching, and air-cooling-quenching conditions and a drastic increase in the specimen that experienced a furnace-cooling-quenching condition.The cooling γ′ precipitates have unimodal distributions after quenching at the air-cooling rate and bimodal distributions after quenching at the furnace-cooling rate, but there are not these distributions in the specimens that experienced iced-brine-quenching and oil-quenching conditions.When aging at 760°C, the size of primary aging γ′ precipitates appears unaffected in the specimens that experienced iced-brine-quenching, oil-quenching, and air-cooling-quenching conditions.However, it has a drastic increase in the specimen that experienced a furnace-cooling-quenching condition, and it is interesting that the bigger cooling γ′ precipitates have a coalescence and octodendritic shape.The microhardness study indicates that the hardness has no variation in the specimens that experienced iced-brine-quenching, oil-quenching, and air-cooling-quenching conditions and has a drastic decrease in the specimens that experienced a furnace-cooling-quenching condition and obtains the minimum microhardness value 390.8 HV.The characteristics of γ′ precipitates in a superalloy quenched from 1050°C at different rates were investigated using field emission scanning electron microscope（FESEM）.When quenched from 1050°C, the size of primary aging γ′ precipitates has a small increase in the specimens that experienced iced-brine-quenching, oil-quenching, and air-cooling-quenching conditions and a drastic increase in the specimen that experienced a furnace-cooling-quenching condition.The cooling γ′ precipitates have unimodal distributions after quenching at the air-cooling rate and bimodal distributions after quenching at the furnace-cooling rate, but there are not these distributions in the specimens that experienced iced-brine-quenching and oil-quenching conditions.When aging at 760°C, the size of primary aging γ′ precipitates appears unaffected in the specimens that experienced iced-brine-quenching, oil-quenching, and air-cooling-quenching conditions.However, it has a drastic increase in the specimen that experienced a furnace-cooling-quenching condition, and it is interesting that the bigger cooling γ′ precipitates have a coalescence and octodendritic shape.The microhardness study indicates that the hardness has no variation in the specimens that experienced iced-brine-quenching, oil-quenching, and air-cooling-quenching conditions and has a drastic decrease in the specimens that experienced a furnace-cooling-quenching condition and obtains the minimum microhardness value 390.8 HV.

关 键 词：superalloys precipitates quenching rate microhardness 

分 类 号：TG156.3[金属学及工艺—热处理]