Jiuzhou ZHAO
,
Dongming LIU
,
Hengqiang YE
材料科学技术（英文）
In order to understand the solidification process of an atomized droplet and predict the fraction solidification of droplets with flight distance during spray forming, a numerical model based on the population dynamics approach is developed to describe the microstructure evolution under the common action of the nucleation and growth of grains. The model is coupled with droplets heat transfer controlling equations and solved for Al-4.5~wt~pct Cu alloy. It is demonstrated that the numerical results describe the solidification process well.
关键词:
Rapid solidification
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null
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null
,
null
Jing YU
,
Qingyan XU
,
Baicheng LIU
,
Jiarong LI
,
Hailong YUAN
,
Haipeng JIN
材料科学技术（英文）
The directional solidification process of turbine blade sample castings was investigated in the work. Variable withdrawal rates were used in one withdrawal process and compared with the other using uniform rate. A mathematical model for heat radiation transfer and microstructure simulation of directional solidification process was developed based on CA-FD method. The temperature distribution and microstructure were simulated and compared with the experimental results. The stray grains were predicted and compared with the experimental results. The uneven temperature distribution of platform was the main reason of the formation of stray grains.
关键词:
Turbine blade casting
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null
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null
Shihong ZHANG
,
Zhongtang WANG
,
Bing QIAO
,
Yi XU
,
Tingfeng XU
材料科学技术（英文）
The processing parameters of tube extrusion for superalloy Inconel 718 (IN 718), such as slug temperature, tools temperature, choice of lubricant, extrusion ratio and extrusion speed, were determined by experiment in this paper. An appropriate temperature range recommended for the slug is 1080~1120℃, and the temperature range recommended for the tools is 350~500℃. The microstructural evolution of superalloy IN 718 during tube extrusion was analyzed. With the increase of the deformation the cross crystal grains were slightly refined. While the vertical crystal grain is elongated evidently and the tensile strength increased along the axial rake. Glass lubricants have to be spread on the slug surface after being heated to 150~200℃, vegetable oil or animal oil can be used as the lubricant on the surface of the tools to reduce the extrusion force remarkably.
关键词:
Superalloy IN 718
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null
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null
