| 摘要 |
A method to facilitate the ability to engineer an organized microstructure within a monolithically homogeneous implantable biomaterial, particularly metallic alloys, is provided. By starting with an ultra-fine grained, equiaxed microstructure having an averaged linear grain size of less than 5 microns, a functionally graded microstructure is developed by establishing a temperature gradient across the cross sectional dimension. In the case of a tubular product form, this dimension would be framed by the outer and inner surfaces. By ensuring one surface is held at a substantially lower temperature than the other surface a temperature gradient is developed. The present invention also provides an implantable medical device which includes an organized microstructure. In accordance with the present invention, the organized microstructure includes a first surface region having said ultra-fine grained, equiaxed microstructure and a second surface region comprising a recrystallized, coarser grained microstructure having an average linear grain size of greater than 25 microns, wherein the first and second surface regions are separated by a transition region.
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