摘要
采用差示扫描量热法(DSC)、扫描电镜(SEM)、电子探针(EMPA)等表征方法,对GH925合金的锻态相转变行为、固溶时效态热处理工艺性能及显微组织进行了研究。研究表明合金从室温25~1 100℃升温区间的相转变序列为:MC相(转变温度为540℃-终止析出温度为1 043℃,下同);γ′相(578~978℃);M23C6-M7C3(679~758℃);σ相(723.5~879℃);η相(807~978℃)。合金锻态组织经(990~1 010℃)×2h固溶+740℃-760℃×8h时效处理,可以获得最佳的综合力学性能。1 000℃×2h固溶+780℃×8h时效热处理,沿晶界有大量的脆硬针片状σ相析出,造成合金冲击韧性的急剧下降。
The phase transformation behaviors, solid-solution aging heat treatment processes, mecnanlc proper- ties and microstructure of the forged GH925 alloy were investigated by means of differential scanning calorime- try (DSC), scanning electron microscopy (SEM), electron probe mieroanalysis (EPMA) characterization meth- ods, etc. The research results show that the phase transformation sequence of the forged alloy during elevated temperature from 25 to 1 100 ℃ is MC phase (initial transformation temperature is 540 ℃, terminated transfor- mation temperature is 1 043 ℃, the same below), 7r phase (578-978 ℃), M2sC6-MTCs (679-758 ℃), a phase (723.5-879 ℃ ) and η phase (807-978 ℃). The optimum comprehensive mechanical properties of the forged alloy can be obtained by 990-1 010 ℃ × 2 h solid-solution and 740-760 ℃ × 8 h aging heat-treatment. An amount of hard and brittle needle flake σ phase precipitates along the grain boundaries after the heat-treatment of 1 000 ℃ × 2 h solid-solution and 780 ℃ × 8 h aging, resulting in a sharp decline of the aolly's impact toughness at this aging temperature.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2017年第4期4168-4173,4178,共7页
Journal of Functional Materials
基金
河南省科技开放合作资助项目(172106000062)
河南省科技攻关资助项目(162102310400)
河南省高等学校重点科研资助项目(16A430002)
河南工程学院博士基金资助项目(D2015015)
关键词
GH925合金
相转变
差示扫描量热法
热处理
GH925 alloy
phase transformation
differential scanning calorimetry
heat treatment