摘要
为了研究Ni元素对新型钴基高温合金析出相的影响,基于JMatPro热力学模拟计算软件对不同Ni含量下Co-8.8Al-9.8W合金(摩尔分数,%)中平衡相析出的热力学行为进行研究。结果表明:随着Ni含量的增加,合金中γ相的析出温度有降低趋势,析出量减少;与0Ni合金相比,25Ni合金γ相析出温度降低了11.63℃,600℃时35Ni合金γ相的析出量较0Ni合金的减少了20.63%。μ-Co7W6相的析出温度升高;与0Ni合金相比,35Ni合金析出温度升高303.73℃,η-Co3Al相则会消失,而γ′相的析出温度升高,析出量增加;与5Ni合金相比,35Ni合金γ′相析出温度升高392.85℃,600℃时35Ni合金析出量较0Ni合金的增加40.9%。从Ni对平衡相中各元素的影响以及各物相的析出角度来看,随着Ni含量的增加,当γ相析出时固相和液相中各元素的含量相差越来越多,要满足γ相的析出和长大,只有通过降低温度或增加过冷度来实现。从而导致γ相的含量越来越少,析出温度也越来越低。合金中加入的Ni元素以形成γ′相的形式抑制η-Co3Al相的形成与生长,从而导致η相最后消失。从γ相中析出的W和Al元素分别为μ-Co7W6和η-Co3Al提供形核及生长的条件,但η-Co3Al相消失以后,从γ相中析出的Al和Ni元素却为γ′相的生成提供了条件,γ′相开始形成并增加。
In order to study the effect of Ni element on the precipitation of new Co-based superalloy,a research about the thermodynamic behavior of equilibrium phase precipitation of the Co-8.8Al-9.8W alloy with different Ni content was conducted based on JMatPro thermodynamic simulation software.The results show that with the increase of Ni content,the precipitation temperature ofγphase decreases,and the amount of precipitation decreases.Compared with 0Ni alloy,the precipitation temperature ofγphase in 25Ni alloy decreases by 11.63℃,and the precipitation amount ofγphase in 35Ni alloy decreases by 20.63%at 600℃.The precipitation temperature ofμ-Co7W6 phase increases,and the precipitation temperature of 35Ni alloy increases by 303.73℃compared with that of 0Ni alloy.While theη-Co3Al phase will disappear.The precipitation temperature ofγ′phase increases and the amount of precipitation increases.Compared with 5Ni alloy,the precipitation temperature at 35Ni increases by 392.85℃and the precipitation amount at 600℃increases by 40.9%.From the view of the precipitation of each phases the and the influence of Ni on the elements in equilibrium phase,we can see that as the increasing of Ni content,the contents of elements in solid phase and liquid phase become more and more different when theγphase precipitates.Only by decreasing the temperature or increasing the supercooling degree the precipitation and growth ofγphase can be satisfied.As a result,the content ofγphase became less and less,and the precipitation temperature is also lower and lower.The Ni element added in the alloy inhibits the formation and growth ofη-Co3Al phase in a form of generatingγ′phase,which eventually leads to the disappearance ofηphase.W and Al precipitated fromγphase provide nucleation and growth conditions forμ-Co7W6 andη-Co3Al,respectively.However,after the disappearance ofη-Co3Al phase,Al and Ni precipitated fromγphase provide conditions for the formation ofγ′phase,and then theγ′phase begins to generate and increase.
作者
徐仰涛
马宏利
XU Yang-tao;MA Hong-li(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2019年第11期2533-2539,共7页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(51561019)~~
