镍基高温合金长期时效过程中第二相的析出

Secondarily Precipitated Phases of a Ni-Based Superalloy During Durable Thermal Treatment

为考察合金在高温长期时效过程中的组织变化情况,使合金分别在800℃,900℃进行了100～1000h的长期时效,并对由镍基基体上析出的第二相粒子利用扫描电镜、透射电镜、电子探针等测试手段进行了观察与分析·发现碳化物和TCP相的析出有着类似之处,都在800℃时效时比在更高温度时效容易析出,颗粒尺寸也大于900℃时效时的尺寸;观察到析出碳化物种类有M23C6型、M7C3型;TCP相种类有μ相、σ相·通过测量γ′相的平均半径得到其析出特性符合里夫希茨·瓦格纳的第二相粒子成熟理论·相与组织的准确确定,为其后确定合金的拉伸与持久性能提供了有力的分析基础·

A Ni-based superalloy was heated as durable ageing treatment at 800℃ and 900℃ for 100～1000hr to observe its change in microstructures. Further, the samples of secondarily precipitated phases in the aging treatment process were analyzed by means of SEM, TEM and electro-probe. It was found that both the carbide and TCP-phase precipitates are easier to be precipitated at 800℃ than at higher temperature and their particle sizes are bigger at 800℃ than at 900℃. The types of precipitated carbides are M_(23)C_6 and M_7C_3 phases, while those of TCP phases are μ and σ. The average radiu of γ′-phase grains, as measured, provides such a conclusion that their precipitation behavior is coincident with Liftshitz-Wagner theory. As a result, the investigation as above offers a foundation on which the examination of tensile and duration properties are available.