Qiang LI
,
Yongbo XU
,
Zuhan LAI
,
Letian SHEN
,
Yilong BAI
材料科学技术（英文）
Recrystallized grains, less than 200 nm in diameter were observed in heavily shear zones of a high strength low alloy steel and a Ni-based alloy, and Also grain refinement, less than 3 μm in diameter was made in high purity aluminum by ECAE at ambient temperature. The experimental results showed that high strain rate and large deformation could induce dynamic recrystallization. Based on dislocation dynamics and grain orientation change enhanced by plastic deformation, a model for the recrystallization process is developed. The model is used to explain the ultra fine grains which are formed at a temperature still much lower than that for the conventional recrystallization.
关键词:
Sugui TIAN
,
Jinghua ZHANG
,
Yongbo XU
,
Zhuangqi HU
,
Hongcai YANG
材料科学技术（英文）
The microstructures of a single crystal Ni-base superalloy with [001] orientation were observed by means of TEM. Results showed that the fine gamma' particles were precipitated in the gamma matrix channels during the tensile deformation of the alloy. Thermodynamics analysis indicated that the solubility of elements M(Al,Ta) within the gamma matrix may be changed when the alloy was deformed by the external applied stress. The tensile stress reduced the solubility of elements Al and Ta so as to occur the over-saturation and agglomeration of them, which promoted the precipitation of fine gamma'-phase in the gamma matrix.
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