基于CALPHAD方法对GH3128合金析出相的热力学模拟计算和应用

采用CALPHAD方法对镍基GH3128合金析出相规律进行研究并对成分优化。研究表明,GH3128主要有害析出相为μ相,其主要化学组成为(NiCr)₃ (WMo)2。随着W、Mo、Cr含量的升高,导致μ相的析出量增加,但添加17%Cr,将诱导μ相转变为σ相,造成μ相析出量减少。随着C含量增加,不仅碳化物析出量升高,还会导致γ’相析出量减少,但C含量低于0.02%时,在700℃时会促使μ相析出。此外,随着Al、Ti含量增加,虽然γ’相析出量增加,但同样促使σ相析出。通过对GH3128镍基合金成分优化(/%:0.032C,20.10Cr,8.02W,7.92Mo,0.72Al,0.62Ti,0.30Fe,0.005B,0.06Zr,0.05Ce,0.35Mn,0.43Si),可使合金工作温度900℃以上无有害相析出,有害相σ析出量则有所降低。

Thermodynamic Simulation of GH3128 Alloy Based on CALPHAD Method and Application

 CALPHAD method is used to study and optimize the composition of Ni-based GH3128 alloy and the law of precipitate phase. The results show that the main harmful precipitated phase in GH3128 is phase μ and its principle chemical composition is (NiCr)₃ ( WMo)₂. With the increase of W, Mo and Cr content, the precipitated amount of phase μ increases. But addition of 17%Cr induces the transformation of phase μ into phase σ resulting in the decrease of phase μ precipitation decreases. With C content increased, the amount of carbide precipitation increases, not only can also lead to decrease of precitated amount of γ’ phase, but as C content lower than 0.02% , to prompte phase μ precipitated at 700℃ . As the elements of Al and Ti increase, although the amount of γ’ phase precipitation increases, the a phase is also precipitated. Therefore, Through GH3128 Ni-based alloy composition optimization (/% : 0.032C, 20. l0Cr, 8.02W, 7.92Mo, 0.72A1, 0.62Ti,0.30Fe,0.005B,0.06Zr,0.05Ce,0.35Mn,0.43Si) , it can make the alloy at the working temperature above 900℃; without harmful phase and harmful a phase precipitation amount is reduced.