双螺旋搅拌工艺制备了AZ91D合金半固态浆料,获得金属半固态加工要求的细小、等轴分布均匀的非枝晶组织.研究了熔体温度、搅拌速度和剪切时间对该组织的影响规律.结果表明:采用合适的搅拌工艺,可获得金属半固态加工要求的细小、等轴分布均匀的非枝晶组织.即降低降体温度、搅拌速度及适当剪切时间有利于细小球形晶粒的形成.加大搅拌速度及合理搅拌时间可以细化晶粒,主要是由于是高剪切作用下熔体获得一个非常均匀温度场,从而增加有效形核的缘故.
The AZ91D semisolid slurry was prepared by twin-screw stirring method. The influences of melt temperature, rotation speed and shearing time on the size and morphology of α-Mg were investigated. The results showed that fine equiaxed grain could be obtained by proper stirring process. The melt temperature, stirring speed and proper shearing time were beneficial to the formation of fine globular grains. Increasing the stirring speed and reasonable time could give rise to substantial grain refinement during shearing stage, which can be attributed to the increase of effective nucleation rate caused by the extremely uniform temperature due to a high shear rate and a high degree of turbulence.
参考文献
| [1] | Flemings M C .Behavior of metal alloys in the semisolid state[J].Metallurgical and Materials Transactions B:Process Metallurgy and Materials Processing Science,1991,22B(06):269. |
| [2] | Kirkwood D H .Semisolid metal processing[J].International Materials Reviews,1994,39(05):173. |
| [3] | Z. Fan .Semisolid metal processing[J].International Materials Reviews,2002(2):49-85. |
| [4] | 管仁国,李俊鹏,石路,温景林.倾斜式冷却剪切制备半固态Al-Mg合金[J].东北大学学报（自然科学版）,2005(05):448-451. |
| [5] | 张凯,张奎,李兴刚,徐玉磊,雷健,袁海波.钇在AZ91D镁合金熔体中溶解机制的实验研究[J].稀有金属,2008(06):689-693. |
| [6] | Mao Weimin;Zhao Aimin;Li Yanjun .The formation mechanism of non-dendritic primary alpha-Al phase in semi-solid AISi_7 Mg alloy[J].Science and Technology of Advanced Materials,2001,29(01):97. |
| [7] | Chen C P;Tsao C Y .A response of spray-depoeited stirred-cast and conventional cast Pb-Sn alloys to deformation in semi-solid state[J].Mates Sci,1995,43(06):4019. |
| [8] | Fan Z;Liu G;Hitchcock M.Solidification behavior under intensive forced convection[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,2005(413-414):229. |
| [9] | Ji S;Fan Z;Bevis M J .Semi-solid processing of engineering alloys by a twin-screw rheomoulding process[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,2001,A299:210. |
| [10] | M.Kitayama;K.Hirao;M.Toriyama .Modeling and simulation of grain growth in Si_3N_4-I. anisotropic Ostwald ripening[J].Acta materialia,1998(18):6541-6550. |
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