Localized High-Pressure Torsion for Thick Workpiece Grain Refinement

The workpiece processing is segmented into two distinct zones: a heated zone where high-pressure torsion is applied for fine-grain development, and a non-heated zone that remains in ambient conditions. This segmentation allows the complex high-pressure-torsion mechanism to operate only on a portion of the workpiece, reducing overall device complexity and cost while maintaining effective grain structure control in the processed region.

The patent applies local heating to create a temperature gradient along the workpiece, enabling high-pressure torsion to be effective only in the heated region where material becomes more ductile. This local quality approach concentrates the complex processing mechanism where needed, rather than requiring the entire workpiece to undergo complex high-pressure torsion, thereby reducing device complexity.

The workpiece is divided into a processed zone receiving high-pressure torsion and energy input, and an unprocessed zone operating under ambient conditions. This segmentation ensures that energy-intensive heating and high-pressure torsion operations are confined to only the portion of the workpiece requiring property improvement, significantly reducing overall energy consumption while maintaining enhanced strength and ductility in the processed region.

Instead of applying high-pressure torsion to the entire workpiece, the patent applies the process partially to a specific segment. This partial action approach provides sufficient energy input to achieve the desired material property improvements in the critical region without the excessive energy consumption that would result from processing the entire workpiece.

The patent creates a localized heated zone within the workpiece using induction heating or radiant heating applied to a specific region. This local heating softens the material in that region, enabling high-pressure torsion to effectively process thicker sections without requiring the entire workpiece to be heated or processed, thereby avoiding the need for increasingly complex device designs as workpiece thickness increases.

The patent applies preliminary heating to the workpiece region before applying high-pressure torsion. This preliminary action of heating the material beforehand reduces its flow stress and increases ductility, enabling the subsequent high-pressure torsion to effectively process thicker workpieces without requiring proportionally more complex processing systems.