镍基耐蚀合金925均匀化及固溶过程组织演变规律

Microstructure Evolution of 925 Alloy during Homogenisation and Solution Treatment

摘要:

为研究925合金在均匀化及固溶过程中组织演变规律,利用金相显微镜、扫描电镜和能谱分析等对经真空感应熔炼(VIM)和保护气氛下电渣重熔(ESR)双联工艺冶炼的925合金的原始铸态、均匀化态、锻态和固溶态的组织和析出相进行分析。结果表明：铸态组织中含有TiN、MC、γ′相、σ相以及η相；1160℃退火5h可使γ′相、σ相及η相回溶,退火20h偏析基本消除；在950-1070℃固溶过程中,M₂₃C₆相在晶界析出量逐渐减少,1040℃以上晶粒急剧长大。

Abstract:

In order to investigate the microstructure evolution of 925 alloy during homogenization and solution treatment, nickel-based superalloy 925 alloy ingots of vacuum-induction-melting and electroslag-remelting were prepared and homogenization and solution tests were carried out. The microstructure and precipitations of 925 samples were studied by optical microscopy,scanning electron microscopy,and energy dispersive spectroscopy．It is found that there exist phases such as TiN, MC, σ phase, γ′ phase and η phase in the ingots， and σ phase, γ′ phase and η phase can be remelted in 1160℃ after 5h. After homogenization at 1160℃ for 20 h,this segregation can almost be eliminated. In solution treatment range of 950℃ to 1070℃, the amount of grain boundary precipitation of M₂₃C₆ decreases gradually and the grain size increases quickly.