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为研究B元素对新型钴基高温合金析出相的影响,基于JMat Pro热力学模拟计算软件对不同B含量下Co-8.8Al-9.8W合金的平衡相析出行为进行了研究。结果表明:B含量的增加,会导致γ相、μ-Co_7W_6相析出温度的降低,并减少γ相、μ-Co_7W_6相析出量,相反会提高η-Co_3Al相的析出温度及析出量。针对这一计算结果,从B对平衡相中各元素的影响,硼化物的析出等角度分析,给出了解释。分析认为,随着B含量的增加,使γ相析出时固液平衡相中各元素的含量相差越来越多,要满足γ相的形核和长大,只有降低温度增加过冷度来实现。从而导致随着B含量的增加,γ相的含量越来越少,析出温度越来越低。硼化物的析出,固溶了大量的Co、W,使固液平衡相中Al的含量增加,促进了Co_3Al的析出。
In order to study the influence of element B on the precipitates of new cobalt-base superalloy, the equilibrium phase precipitation behavior of Co-8.8Al-9.8W alloy with different B content was studied based on the thermodynamic simulation software JMat Pro. The results show that the increase of B content leads to the decrease of precipitation temperature of γ-phase and μ-Co_7W_6 phase and the precipitation of γ-phase and μ-Co_7W_6 phase. On the contrary, the precipitation temperature and precipitation amount of η-Co_3Al phase increase. According to the calculation results, this paper gives an explanation from the influence of B on the elements in the equilibrium phase and the precipitation of borides. The analysis shows that with the increase of B content, the amount of each element in the solid-liquid equilibrium phase is more and more different when the γ phase is precipitated, so that the nucleation and growth of the γ phase are satisfied, and only the decrease of the temperature increases the degree of undercooling . As a result, with the increase of B content, the content of γ phase is less and less, and the precipitation temperature is getting lower and lower. Boride precipitation, solid solution a large number of Co, W, so that solid-liquid equilibrium phase of Al content increased, and promote the precipitation of Co_3Al.